From patchwork Thu Mar 4 06:16:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alistair Popple X-Patchwork-Id: 12115523 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A04CC433E0 for ; Thu, 4 Mar 2021 06:16:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D158964EE3 for ; Thu, 4 Mar 2021 06:16:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D158964EE3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 74FE46B0006; Thu, 4 Mar 2021 01:16:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 728CE6B0007; Thu, 4 Mar 2021 01:16:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5CB106B0008; Thu, 4 Mar 2021 01:16:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 4225A6B0006 for ; Thu, 4 Mar 2021 01:16:58 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id E8112181D9004 for ; Thu, 4 Mar 2021 06:16:57 +0000 (UTC) X-FDA: 77881183674.23.2EAD478 Received: from hqnvemgate26.nvidia.com (hqnvemgate26.nvidia.com [216.228.121.65]) by imf03.hostedemail.com (Postfix) with ESMTP id CE28BC0007C1 for ; Thu, 4 Mar 2021 06:16:55 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 03 Mar 2021 22:16:55 -0800 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:16:55 +0000 Received: from localhost (172.20.145.6) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:16:54 +0000 From: Alistair Popple To: , , , CC: , , , , , , , "Alistair Popple" Subject: [PATCH v4 1/8] mm: Remove special swap entry functions Date: Thu, 4 Mar 2021 17:16:38 +1100 Message-ID: <20210304061645.29747-2-apopple@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210304061645.29747-1-apopple@nvidia.com> References: <20210304061645.29747-1-apopple@nvidia.com> MIME-Version: 1.0 X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To DRHQMAIL107.nvidia.com (10.27.9.16) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1614838615; bh=6phE4x1NIuT8ANY+v15jxQFMulobxzGnKOdFMxNOIPc=; h=From:To:CC:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding:Content-Type: X-Originating-IP:X-ClientProxiedBy; b=NSYLvynFnYlg+tdldYhrVdoGEZ8fyGoI+iq+aAe54Kyg9nOeq5lD4I9PoNKB/n4sR cbUulT31RJUrG16IMdEdDaAK8T1p1Brftu3aLtTvHhrFUuvSxJ2ivPl+pGdRIOiqS2 p+lzztxVx7yOIXPq22IZMfyG80aYsHE6g7JpqH16q+ekWvS7yEVM+hFOEwu+WkEPlL CAwTT2s4FTWFOF93jKAJXN3piukBWPbG0IdoYvsXx2d6g+fdu6ihKfnYy4jpfCjLR8 Rzcx7uSvikVdcF4oUjpkWecNFY0f9VXiRcWymlkP6IiLuECKYdXv85OTNZQ+B2evoO JGdp3zIjzq1qQ== X-Stat-Signature: 6md49hhssx9bgs8mgmyi8zix6jreb5ue X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: CE28BC0007C1 Received-SPF: none (nvidia.com>: No applicable sender policy available) receiver=imf03; identity=mailfrom; envelope-from=""; helo=hqnvemgate26.nvidia.com; client-ip=216.228.121.65 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614838615-913898 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Remove the migration and device private entry_to_page() and entry_to_pfn() inline functions and instead open code them directly. This results in shorter code which is easier to understand. Signed-off-by: Alistair Popple Reviewed-by: Ralph Campbell --- v4: * Added pfn_swap_entry_to_page() * Reinstated check that migration entries point to locked pages * Removed #define swapcache_prepare which isn't needed for CONFIG_SWAP=0 builds --- arch/s390/mm/pgtable.c | 2 +- fs/proc/task_mmu.c | 23 +++++--------- include/linux/swap.h | 4 +-- include/linux/swapops.h | 69 ++++++++++++++--------------------------- mm/hmm.c | 5 ++- mm/huge_memory.c | 4 +-- mm/memcontrol.c | 2 +- mm/memory.c | 10 +++--- mm/migrate.c | 6 ++-- mm/page_vma_mapped.c | 6 ++-- 10 files changed, 50 insertions(+), 81 deletions(-) diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 18205f851c24..aae001096c46 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -691,7 +691,7 @@ static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry) if (!non_swap_entry(entry)) dec_mm_counter(mm, MM_SWAPENTS); else if (is_migration_entry(entry)) { - struct page *page = migration_entry_to_page(entry); + struct page *page = pfn_swap_entry_to_page(entry)); dec_mm_counter(mm, mm_counter(page)); } diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 602e3a52884d..7c75af0fc423 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -514,10 +514,8 @@ static void smaps_pte_entry(pte_t *pte, unsigned long addr, } else { mss->swap_pss += (u64)PAGE_SIZE << PSS_SHIFT; } - } else if (is_migration_entry(swpent)) - page = migration_entry_to_page(swpent); - else if (is_device_private_entry(swpent)) - page = device_private_entry_to_page(swpent); + } else if (is_pfn_swap_entry(swpent)) + page = pfn_swap_entry_to_page(swpent); } else if (unlikely(IS_ENABLED(CONFIG_SHMEM) && mss->check_shmem_swap && pte_none(*pte))) { page = xa_load(&vma->vm_file->f_mapping->i_pages, @@ -549,7 +547,7 @@ static void smaps_pmd_entry(pmd_t *pmd, unsigned long addr, swp_entry_t entry = pmd_to_swp_entry(*pmd); if (is_migration_entry(entry)) - page = migration_entry_to_page(entry); + page = pfn_swap_entry_to_page(entry); } if (IS_ERR_OR_NULL(page)) return; @@ -691,10 +689,8 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, } else if (is_swap_pte(*pte)) { swp_entry_t swpent = pte_to_swp_entry(*pte); - if (is_migration_entry(swpent)) - page = migration_entry_to_page(swpent); - else if (is_device_private_entry(swpent)) - page = device_private_entry_to_page(swpent); + if (is_pfn_swap_entry(swpent)) + page = pfn_swap_entry_to_page(swpent); } if (page) { int mapcount = page_mapcount(page); @@ -1382,11 +1378,8 @@ static pagemap_entry_t pte_to_pagemap_entry(struct pagemapread *pm, frame = swp_type(entry) | (swp_offset(entry) << MAX_SWAPFILES_SHIFT); flags |= PM_SWAP; - if (is_migration_entry(entry)) - page = migration_entry_to_page(entry); - - if (is_device_private_entry(entry)) - page = device_private_entry_to_page(entry); + if (is_pfn_swap_entry(entry)) + page = pfn_swap_entry_to_page(entry); } if (page && !PageAnon(page)) @@ -1443,7 +1436,7 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, if (pmd_swp_soft_dirty(pmd)) flags |= PM_SOFT_DIRTY; VM_BUG_ON(!is_pmd_migration_entry(pmd)); - page = migration_entry_to_page(entry); + page = pfn_swap_entry_to_page(entry); } #endif diff --git a/include/linux/swap.h b/include/linux/swap.h index 596bc2f4d9b0..57a7690966a4 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -519,8 +519,8 @@ static inline void show_swap_cache_info(void) { } -#define free_swap_and_cache(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) -#define swapcache_prepare(e) ({(is_migration_entry(e) || is_device_private_entry(e));}) +/* used to sanity check ptes in zap_pte_range when CONFIG_SWAP=0 */ +#define free_swap_and_cache(e) is_pfn_swap_entry(e) static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) { diff --git a/include/linux/swapops.h b/include/linux/swapops.h index d9b7c9132c2f..3fd88081107c 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -121,16 +121,6 @@ static inline bool is_write_device_private_entry(swp_entry_t entry) { return unlikely(swp_type(entry) == SWP_DEVICE_WRITE); } - -static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry) -{ - return swp_offset(entry); -} - -static inline struct page *device_private_entry_to_page(swp_entry_t entry) -{ - return pfn_to_page(swp_offset(entry)); -} #else /* CONFIG_DEVICE_PRIVATE */ static inline swp_entry_t make_device_private_entry(struct page *page, bool write) { @@ -150,16 +140,6 @@ static inline bool is_write_device_private_entry(swp_entry_t entry) { return false; } - -static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry) -{ - return 0; -} - -static inline struct page *device_private_entry_to_page(swp_entry_t entry) -{ - return NULL; -} #endif /* CONFIG_DEVICE_PRIVATE */ #ifdef CONFIG_MIGRATION @@ -182,22 +162,6 @@ static inline int is_write_migration_entry(swp_entry_t entry) return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); } -static inline unsigned long migration_entry_to_pfn(swp_entry_t entry) -{ - return swp_offset(entry); -} - -static inline struct page *migration_entry_to_page(swp_entry_t entry) -{ - struct page *p = pfn_to_page(swp_offset(entry)); - /* - * Any use of migration entries may only occur while the - * corresponding page is locked - */ - BUG_ON(!PageLocked(compound_head(p))); - return p; -} - static inline void make_migration_entry_read(swp_entry_t *entry) { *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); @@ -217,16 +181,6 @@ static inline int is_migration_entry(swp_entry_t swp) return 0; } -static inline unsigned long migration_entry_to_pfn(swp_entry_t entry) -{ - return 0; -} - -static inline struct page *migration_entry_to_page(swp_entry_t entry) -{ - return NULL; -} - static inline void make_migration_entry_read(swp_entry_t *entryp) { } static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, spinlock_t *ptl) { } @@ -241,6 +195,29 @@ static inline int is_write_migration_entry(swp_entry_t entry) #endif +static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry) +{ + struct page *p = pfn_to_page(swp_offset(entry)); + + /* + * Any use of migration entries may only occur while the + * corresponding page is locked + */ + BUG_ON(is_migration_entry(entry) && !PageLocked(compound_head(p))); + + return p; +} + +/* + * A pfn swap entry is a special type of swap entry that always has a pfn stored + * in the swap offset. They are used to represent unaddressable device memory + * and to restrict access to a page undergoing migration. + */ +static inline bool is_pfn_swap_entry(swp_entry_t entry) +{ + return is_migration_entry(entry) || is_device_private_entry(entry); +} + struct page_vma_mapped_walk; #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION diff --git a/mm/hmm.c b/mm/hmm.c index 943cb2ba4442..3b2dda71d0ed 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -214,7 +214,7 @@ static inline bool hmm_is_device_private_entry(struct hmm_range *range, swp_entry_t entry) { return is_device_private_entry(entry) && - device_private_entry_to_page(entry)->pgmap->owner == + pfn_swap_entry_to_page(entry)->pgmap->owner == range->dev_private_owner; } @@ -257,8 +257,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, cpu_flags = HMM_PFN_VALID; if (is_write_device_private_entry(entry)) cpu_flags |= HMM_PFN_WRITE; - *hmm_pfn = device_private_entry_to_pfn(entry) | - cpu_flags; + *hmm_pfn = swp_offset(entry) | cpu_flags; return 0; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 91ca9b103ee5..d65eebf446ae 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1695,7 +1695,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); entry = pmd_to_swp_entry(orig_pmd); - page = pfn_to_page(swp_offset(entry)); + page = pfn_swap_entry_to_page(entry); flush_needed = 0; } else WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); @@ -2103,7 +2103,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, swp_entry_t entry; entry = pmd_to_swp_entry(old_pmd); - page = pfn_to_page(swp_offset(entry)); + page = pfn_swap_entry_to_page(entry); write = is_write_migration_entry(entry); young = false; soft_dirty = pmd_swp_soft_dirty(old_pmd); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 913c2b9e5c72..9fa9ec9d0ace 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5544,7 +5544,7 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, * as special swap entry in the CPU page table. */ if (is_device_private_entry(ent)) { - page = device_private_entry_to_page(ent); + page = pfn_swap_entry_to_page(ent); /* * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have * a refcount of 1 when free (unlike normal page) diff --git a/mm/memory.c b/mm/memory.c index feff48e1465a..99a6a695b1b1 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -718,7 +718,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, } rss[MM_SWAPENTS]++; } else if (is_migration_entry(entry)) { - page = migration_entry_to_page(entry); + page = pfn_swap_entry_to_page(entry); rss[mm_counter(page)]++; @@ -737,7 +737,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, set_pte_at(src_mm, addr, src_pte, pte); } } else if (is_device_private_entry(entry)) { - page = device_private_entry_to_page(entry); + page = pfn_swap_entry_to_page(entry); /* * Update rss count even for unaddressable pages, as @@ -1274,7 +1274,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, entry = pte_to_swp_entry(ptent); if (is_device_private_entry(entry)) { - struct page *page = device_private_entry_to_page(entry); + struct page *page = pfn_swap_entry_to_page(entry); if (unlikely(details && details->check_mapping)) { /* @@ -1303,7 +1303,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, else if (is_migration_entry(entry)) { struct page *page; - page = migration_entry_to_page(entry); + page = pfn_swap_entry_to_page(entry); rss[mm_counter(page)]--; } if (unlikely(!free_swap_and_cache(entry))) @@ -3271,7 +3271,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) migration_entry_wait(vma->vm_mm, vmf->pmd, vmf->address); } else if (is_device_private_entry(entry)) { - vmf->page = device_private_entry_to_page(entry); + vmf->page = pfn_swap_entry_to_page(entry); ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); } else if (is_hwpoison_entry(entry)) { ret = VM_FAULT_HWPOISON; diff --git a/mm/migrate.c b/mm/migrate.c index 20ca887ea769..39246907eac3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -321,7 +321,7 @@ void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, if (!is_migration_entry(entry)) goto out; - page = migration_entry_to_page(entry); + page = pfn_swap_entry_to_page(entry); /* * Once page cache replacement of page migration started, page_count @@ -361,7 +361,7 @@ void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd) ptl = pmd_lock(mm, pmd); if (!is_pmd_migration_entry(*pmd)) goto unlock; - page = migration_entry_to_page(pmd_to_swp_entry(*pmd)); + page = pfn_swap_entry_to_page(pmd_to_swp_entry(*pmd)); if (!get_page_unless_zero(page)) goto unlock; spin_unlock(ptl); @@ -2437,7 +2437,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, if (!is_device_private_entry(entry)) goto next; - page = device_private_entry_to_page(entry); + page = pfn_swap_entry_to_page(entry); if (!(migrate->flags & MIGRATE_VMA_SELECT_DEVICE_PRIVATE) || page->pgmap->owner != migrate->pgmap_owner) diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 86e3a3688d59..eed988ab2e81 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -96,7 +96,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw) if (!is_migration_entry(entry)) return false; - pfn = migration_entry_to_pfn(entry); + pfn = swp_offset(entry); } else if (is_swap_pte(*pvmw->pte)) { swp_entry_t entry; @@ -105,7 +105,7 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw) if (!is_device_private_entry(entry)) return false; - pfn = device_private_entry_to_pfn(entry); + pfn = swp_offset(entry); } else { if (!pte_present(*pvmw->pte)) return false; @@ -200,7 +200,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) if (is_migration_entry(pmd_to_swp_entry(*pvmw->pmd))) { swp_entry_t entry = pmd_to_swp_entry(*pvmw->pmd); - if (migration_entry_to_page(entry) != page) + if (pfn_swap_entry_to_page(entry) != page) return not_found(pvmw); return true; } From patchwork Thu Mar 4 06:16:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alistair Popple X-Patchwork-Id: 12115525 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61E83C433DB for ; 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Thu, 4 Mar 2021 06:17:01 +0000 (UTC) X-FDA: 77881183842.10.EE672C9 Received: from hqnvemgate25.nvidia.com (hqnvemgate25.nvidia.com [216.228.121.64]) by imf08.hostedemail.com (Postfix) with ESMTP id 07BFB80192E9 for ; Thu, 4 Mar 2021 06:16:57 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 03 Mar 2021 22:16:58 -0800 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:16:57 +0000 Received: from localhost (172.20.145.6) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:16:57 +0000 From: Alistair Popple To: , , , CC: , , , , , , , Alistair Popple , Christoph Hellwig , "Jason Gunthorpe" Subject: [PATCH v4 2/8] mm/swapops: Rework swap entry manipulation code Date: Thu, 4 Mar 2021 17:16:39 +1100 Message-ID: <20210304061645.29747-3-apopple@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210304061645.29747-1-apopple@nvidia.com> References: <20210304061645.29747-1-apopple@nvidia.com> MIME-Version: 1.0 X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To DRHQMAIL107.nvidia.com (10.27.9.16) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1614838618; bh=vmakt/yNlTT7YYAdjyoMaPpkazAgjtUnTBP/cCUHxPo=; h=From:To:CC:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding:Content-Type: X-Originating-IP:X-ClientProxiedBy; b=DeqjjUvBqYX6bG0AO5q/c/DCQpocPniWhKvn3JZLQgwK+qHe4lwxYhk9WYzpKbJ18 rDsEbkcVvyeLbqyQr4pslTrYx7FdOm7YfAqak9E5iEPsJjn2kUtOWv0FxWeE/BE66p o+cqSsHjTtM6xPPl0O3KJTd3v1hsTAkCAsQHGnU2tXhTbMUFTVQP4Jz0hVMLWR1c5l OxfC8qv4Btrmedk7fwEHiXCAzgXI03Vz9waTTZRV7lnuPKxcZZfUsDjZwEwJ3ajjVe ZbKv/xpx4aJKd9mLr7s5drTDz5Fi/AuIMujHU+beiP1rCRDYUeXPyfGOqRk5bh0vkY 5e9licMe9z2Pg== X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 07BFB80192E9 X-Stat-Signature: oe8xgdhdgdme6t4yny95faf81ddw1tw5 Received-SPF: none (nvidia.com>: No applicable sender policy available) receiver=imf08; identity=mailfrom; envelope-from=""; helo=hqnvemgate25.nvidia.com; client-ip=216.228.121.64 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614838617-815801 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Both migration and device private pages use special swap entries that are manipluated by a range of inline functions. The arguments to these are somewhat inconsitent so rework them to remove flag type arguments and to make the arguments similar for both read and write entry creation. Signed-off-by: Alistair Popple Reviewed-by: Christoph Hellwig Reviewed-by: Jason Gunthorpe Reviewed-by: Ralph Campbell --- include/linux/swapops.h | 56 ++++++++++++++++++++++------------------- mm/debug_vm_pgtable.c | 12 ++++----- mm/hmm.c | 2 +- mm/huge_memory.c | 26 +++++++++++++------ mm/hugetlb.c | 10 +++++--- mm/memory.c | 10 +++++--- mm/migrate.c | 26 ++++++++++++++----- mm/mprotect.c | 10 +++++--- mm/rmap.c | 10 +++++--- 9 files changed, 100 insertions(+), 62 deletions(-) diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 3fd88081107c..81008b0179cc 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -100,35 +100,35 @@ static inline void *swp_to_radix_entry(swp_entry_t entry) } #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) -static inline swp_entry_t make_device_private_entry(struct page *page, bool write) +static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset) { - return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ, - page_to_pfn(page)); + return swp_entry(SWP_DEVICE_READ, offset); } -static inline bool is_device_private_entry(swp_entry_t entry) +static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset) { - int type = swp_type(entry); - return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE; + return swp_entry(SWP_DEVICE_WRITE, offset); } -static inline void make_device_private_entry_read(swp_entry_t *entry) +static inline bool is_device_private_entry(swp_entry_t entry) { - *entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry)); + int type = swp_type(entry); + return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE; } -static inline bool is_write_device_private_entry(swp_entry_t entry) +static inline bool is_writable_device_private_entry(swp_entry_t entry) { return unlikely(swp_type(entry) == SWP_DEVICE_WRITE); } #else /* CONFIG_DEVICE_PRIVATE */ -static inline swp_entry_t make_device_private_entry(struct page *page, bool write) +static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset) { return swp_entry(0, 0); } -static inline void make_device_private_entry_read(swp_entry_t *entry) +static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset) { + return swp_entry(0, 0); } static inline bool is_device_private_entry(swp_entry_t entry) @@ -136,35 +136,32 @@ static inline bool is_device_private_entry(swp_entry_t entry) return false; } -static inline bool is_write_device_private_entry(swp_entry_t entry) +static inline bool is_writable_device_private_entry(swp_entry_t entry) { return false; } #endif /* CONFIG_DEVICE_PRIVATE */ #ifdef CONFIG_MIGRATION -static inline swp_entry_t make_migration_entry(struct page *page, int write) -{ - BUG_ON(!PageLocked(compound_head(page))); - - return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ, - page_to_pfn(page)); -} - static inline int is_migration_entry(swp_entry_t entry) { return unlikely(swp_type(entry) == SWP_MIGRATION_READ || swp_type(entry) == SWP_MIGRATION_WRITE); } -static inline int is_write_migration_entry(swp_entry_t entry) +static inline int is_writable_migration_entry(swp_entry_t entry) { return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); } -static inline void make_migration_entry_read(swp_entry_t *entry) +static inline swp_entry_t make_readable_migration_entry(pgoff_t offset) { - *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); + return swp_entry(SWP_MIGRATION_READ, offset); +} + +static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) +{ + return swp_entry(SWP_MIGRATION_WRITE, offset); } extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, @@ -174,21 +171,28 @@ extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, extern void migration_entry_wait_huge(struct vm_area_struct *vma, struct mm_struct *mm, pte_t *pte); #else +static inline swp_entry_t make_readable_migration_entry(pgoff_t offset) +{ + return swp_entry(0, 0); +} + +static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) +{ + return swp_entry(0, 0); +} -#define make_migration_entry(page, write) swp_entry(0, 0) static inline int is_migration_entry(swp_entry_t swp) { return 0; } -static inline void make_migration_entry_read(swp_entry_t *entryp) { } static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, spinlock_t *ptl) { } static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, unsigned long address) { } static inline void migration_entry_wait_huge(struct vm_area_struct *vma, struct mm_struct *mm, pte_t *pte) { } -static inline int is_write_migration_entry(swp_entry_t entry) +static inline int is_writable_migration_entry(swp_entry_t entry) { return 0; } diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index c05d9dcf7891..4932f65a88d4 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -772,17 +772,17 @@ static void __init swap_migration_tests(void) * locked, otherwise it stumbles upon a BUG_ON(). */ __SetPageLocked(page); - swp = make_migration_entry(page, 1); + swp = make_writable_migration_entry(page_to_pfn(page)); WARN_ON(!is_migration_entry(swp)); - WARN_ON(!is_write_migration_entry(swp)); + WARN_ON(!is_writable_migration_entry(swp)); - make_migration_entry_read(&swp); + swp = make_readable_migration_entry(swp_offset(swp)); WARN_ON(!is_migration_entry(swp)); - WARN_ON(is_write_migration_entry(swp)); + WARN_ON(is_writable_migration_entry(swp)); - swp = make_migration_entry(page, 0); + swp = make_readable_migration_entry(page_to_pfn(page)); WARN_ON(!is_migration_entry(swp)); - WARN_ON(is_write_migration_entry(swp)); + WARN_ON(is_writable_migration_entry(swp)); __ClearPageLocked(page); __free_page(page); } diff --git a/mm/hmm.c b/mm/hmm.c index 3b2dda71d0ed..11df3ca30b82 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -255,7 +255,7 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, */ if (hmm_is_device_private_entry(range, entry)) { cpu_flags = HMM_PFN_VALID; - if (is_write_device_private_entry(entry)) + if (is_writable_device_private_entry(entry)) cpu_flags |= HMM_PFN_WRITE; *hmm_pfn = swp_offset(entry) | cpu_flags; return 0; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d65eebf446ae..cb3bc9d3ed3a 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1046,8 +1046,9 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, swp_entry_t entry = pmd_to_swp_entry(pmd); VM_BUG_ON(!is_pmd_migration_entry(pmd)); - if (is_write_migration_entry(entry)) { - make_migration_entry_read(&entry); + if (is_writable_migration_entry(entry)) { + entry = make_readable_migration_entry( + swp_offset(entry)); pmd = swp_entry_to_pmd(entry); if (pmd_swp_soft_dirty(*src_pmd)) pmd = pmd_swp_mksoft_dirty(pmd); @@ -1820,13 +1821,14 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, swp_entry_t entry = pmd_to_swp_entry(*pmd); VM_BUG_ON(!is_pmd_migration_entry(*pmd)); - if (is_write_migration_entry(entry)) { + if (is_writable_migration_entry(entry)) { pmd_t newpmd; /* * A protection check is difficult so * just be safe and disable write */ - make_migration_entry_read(&entry); + entry = make_readable_migration_entry( + swp_offset(entry)); newpmd = swp_entry_to_pmd(entry); if (pmd_swp_soft_dirty(*pmd)) newpmd = pmd_swp_mksoft_dirty(newpmd); @@ -2104,7 +2106,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, entry = pmd_to_swp_entry(old_pmd); page = pfn_swap_entry_to_page(entry); - write = is_write_migration_entry(entry); + write = is_writable_migration_entry(entry); young = false; soft_dirty = pmd_swp_soft_dirty(old_pmd); uffd_wp = pmd_swp_uffd_wp(old_pmd); @@ -2136,7 +2138,12 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, */ if (freeze || pmd_migration) { swp_entry_t swp_entry; - swp_entry = make_migration_entry(page + i, write); + if (write) + swp_entry = make_writable_migration_entry( + page_to_pfn(page + i)); + else + swp_entry = make_readable_migration_entry( + page_to_pfn(page + i)); entry = swp_entry_to_pte(swp_entry); if (soft_dirty) entry = pte_swp_mksoft_dirty(entry); @@ -2988,7 +2995,10 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, pmdval = pmdp_invalidate(vma, address, pvmw->pmd); if (pmd_dirty(pmdval)) set_page_dirty(page); - entry = make_migration_entry(page, pmd_write(pmdval)); + if (pmd_write(pmdval)) + entry = make_writable_migration_entry(page_to_pfn(page)); + else + entry = make_readable_migration_entry(page_to_pfn(page)); pmdswp = swp_entry_to_pmd(entry); if (pmd_soft_dirty(pmdval)) pmdswp = pmd_swp_mksoft_dirty(pmdswp); @@ -3014,7 +3024,7 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) pmde = pmd_mkold(mk_huge_pmd(new, vma->vm_page_prot)); if (pmd_swp_soft_dirty(*pvmw->pmd)) pmde = pmd_mksoft_dirty(pmde); - if (is_write_migration_entry(entry)) + if (is_writable_migration_entry(entry)) pmde = maybe_pmd_mkwrite(pmde, vma); flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4bdb58ab14cb..37cde6d4303c 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3842,12 +3842,13 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, is_hugetlb_entry_hwpoisoned(entry))) { swp_entry_t swp_entry = pte_to_swp_entry(entry); - if (is_write_migration_entry(swp_entry) && cow) { + if (is_writable_migration_entry(swp_entry) && cow) { /* * COW mappings require pages in both * parent and child to be set to read. */ - make_migration_entry_read(&swp_entry); + swp_entry = make_readable_migration_entry( + swp_offset(swp_entry)); entry = swp_entry_to_pte(swp_entry); set_huge_swap_pte_at(src, addr, src_pte, entry, sz); @@ -5019,10 +5020,11 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma, if (unlikely(is_hugetlb_entry_migration(pte))) { swp_entry_t entry = pte_to_swp_entry(pte); - if (is_write_migration_entry(entry)) { + if (is_writable_migration_entry(entry)) { pte_t newpte; - make_migration_entry_read(&entry); + entry = make_readable_migration_entry( + swp_offset(entry)); newpte = swp_entry_to_pte(entry); set_huge_swap_pte_at(mm, address, ptep, newpte, huge_page_size(h)); diff --git a/mm/memory.c b/mm/memory.c index 99a6a695b1b1..957e00525a9a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -722,13 +722,14 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, rss[mm_counter(page)]++; - if (is_write_migration_entry(entry) && + if (is_writable_migration_entry(entry) && is_cow_mapping(vm_flags)) { /* * COW mappings require pages in both * parent and child to be set to read. */ - make_migration_entry_read(&entry); + entry = make_readable_migration_entry( + swp_offset(entry)); pte = swp_entry_to_pte(entry); if (pte_swp_soft_dirty(*src_pte)) pte = pte_swp_mksoft_dirty(pte); @@ -759,9 +760,10 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, * when a device driver is involved (you cannot easily * save and restore device driver state). */ - if (is_write_device_private_entry(entry) && + if (is_writable_device_private_entry(entry) && is_cow_mapping(vm_flags)) { - make_device_private_entry_read(&entry); + entry = make_readable_device_private_entry( + swp_offset(entry)); pte = swp_entry_to_pte(entry); if (pte_swp_uffd_wp(*src_pte)) pte = pte_swp_mkuffd_wp(pte); diff --git a/mm/migrate.c b/mm/migrate.c index 39246907eac3..30c18e7c6089 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -237,13 +237,18 @@ static bool remove_migration_pte(struct page *page, struct vm_area_struct *vma, * Recheck VMA as permissions can change since migration started */ entry = pte_to_swp_entry(*pvmw.pte); - if (is_write_migration_entry(entry)) + if (is_writable_migration_entry(entry)) pte = maybe_mkwrite(pte, vma); else if (pte_swp_uffd_wp(*pvmw.pte)) pte = pte_mkuffd_wp(pte); if (unlikely(is_device_private_page(new))) { - entry = make_device_private_entry(new, pte_write(pte)); + if (pte_write(pte)) + entry = make_writable_device_private_entry( + page_to_pfn(new)); + else + entry = make_readable_device_private_entry( + page_to_pfn(new)); pte = swp_entry_to_pte(entry); if (pte_swp_soft_dirty(*pvmw.pte)) pte = pte_swp_mksoft_dirty(pte); @@ -2445,7 +2450,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, mpfn = migrate_pfn(page_to_pfn(page)) | MIGRATE_PFN_MIGRATE; - if (is_write_device_private_entry(entry)) + if (is_writable_device_private_entry(entry)) mpfn |= MIGRATE_PFN_WRITE; } else { if (!(migrate->flags & MIGRATE_VMA_SELECT_SYSTEM)) @@ -2491,8 +2496,12 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, ptep_get_and_clear(mm, addr, ptep); /* Setup special migration page table entry */ - entry = make_migration_entry(page, mpfn & - MIGRATE_PFN_WRITE); + if (mpfn & MIGRATE_PFN_WRITE) + entry = make_writable_migration_entry( + page_to_pfn(page)); + else + entry = make_readable_migration_entry( + page_to_pfn(page)); swp_pte = swp_entry_to_pte(entry); if (pte_present(pte)) { if (pte_soft_dirty(pte)) @@ -2965,7 +2974,12 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, if (is_device_private_page(page)) { swp_entry_t swp_entry; - swp_entry = make_device_private_entry(page, vma->vm_flags & VM_WRITE); + if (vma->vm_flags & VM_WRITE) + swp_entry = make_writable_device_private_entry( + page_to_pfn(page)); + else + swp_entry = make_readable_device_private_entry( + page_to_pfn(page)); entry = swp_entry_to_pte(swp_entry); } } else { diff --git a/mm/mprotect.c b/mm/mprotect.c index ab709023e9aa..a6c757d87789 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -143,23 +143,25 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, swp_entry_t entry = pte_to_swp_entry(oldpte); pte_t newpte; - if (is_write_migration_entry(entry)) { + if (is_writable_migration_entry(entry)) { /* * A protection check is difficult so * just be safe and disable write */ - make_migration_entry_read(&entry); + entry = make_readable_migration_entry( + swp_offset(entry)); newpte = swp_entry_to_pte(entry); if (pte_swp_soft_dirty(oldpte)) newpte = pte_swp_mksoft_dirty(newpte); if (pte_swp_uffd_wp(oldpte)) newpte = pte_swp_mkuffd_wp(newpte); - } else if (is_write_device_private_entry(entry)) { + } else if (is_writable_device_private_entry(entry)) { /* * We do not preserve soft-dirtiness. See * copy_one_pte() for explanation. */ - make_device_private_entry_read(&entry); + entry = make_readable_device_private_entry( + swp_offset(entry)); newpte = swp_entry_to_pte(entry); if (pte_swp_uffd_wp(oldpte)) newpte = pte_swp_mkuffd_wp(newpte); diff --git a/mm/rmap.c b/mm/rmap.c index 08c56aaf72eb..ef9ef2694c58 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1512,7 +1512,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, * pte. do_swap_page() will wait until the migration * pte is removed and then restart fault handling. */ - entry = make_migration_entry(page, 0); + entry = make_readable_migration_entry(page_to_pfn(page)); swp_pte = swp_entry_to_pte(entry); /* @@ -1608,8 +1608,12 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, * pte. do_swap_page() will wait until the migration * pte is removed and then restart fault handling. */ - entry = make_migration_entry(subpage, - pte_write(pteval)); + if (pte_write(pteval)) + entry = make_writable_migration_entry( + page_to_pfn(subpage)); + else + entry = make_readable_migration_entry( + page_to_pfn(subpage)); swp_pte = swp_entry_to_pte(entry); if (pte_soft_dirty(pteval)) swp_pte = pte_swp_mksoft_dirty(swp_pte); From patchwork Thu Mar 4 06:16:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alistair Popple X-Patchwork-Id: 12115527 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF7C9C433E0 for ; Thu, 4 Mar 2021 06:17:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8A23F64EFE for ; 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Thu, 4 Mar 2021 06:17:03 +0000 (UTC) X-FDA: 77881183926.03.23AC76E Received: from hqnvemgate24.nvidia.com (hqnvemgate24.nvidia.com [216.228.121.143]) by imf22.hostedemail.com (Postfix) with ESMTP id 5C775C0001EA for ; Thu, 4 Mar 2021 06:17:02 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 03 Mar 2021 22:17:02 -0800 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:01 +0000 Received: from localhost (172.20.145.6) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:00 +0000 From: Alistair Popple To: , , , CC: , , , , , , , "Alistair Popple" Subject: [PATCH v4 3/8] mm/rmap: Split try_to_munlock from try_to_unmap Date: Thu, 4 Mar 2021 17:16:40 +1100 Message-ID: <20210304061645.29747-4-apopple@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210304061645.29747-1-apopple@nvidia.com> References: <20210304061645.29747-1-apopple@nvidia.com> MIME-Version: 1.0 X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To DRHQMAIL107.nvidia.com (10.27.9.16) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1614838622; bh=KhCqKR0s83WdeI+iaFfhkOL/c6bb31bkOEArZ0mdKmM=; h=From:To:CC:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding:Content-Type: X-Originating-IP:X-ClientProxiedBy; b=MOGHUVtTdTRRnVM9gq94Dmwzipq4DKEWU/oA5LYFxDM6ZX7YA7eQkrYk885jNhfmF QSnXbyP2K2L9gjAjZ1ZRl+n1UeWMB3mfjslAiwyZfOEW9Moef7fhJprzMz2l8c9uv2 48AEU0/URU0e+PsBkP7Nsh6GCWY31yOCGPt8WJdFSeYFmweKhfS4MidD0tnjz5d485 XjgxMRleBYOPNPkul1FcBHZjn9hSJhTwQIiE3Lhn4aGWjgqamRpWU7BwR7KGEnfHkS xWBEdw+c9HUoPWfjMQ5IevGfoVotudK8WtNfH+uSUTyfKCqYP8Xt4lccSnBa26xAZR dPdBgvENXe0oA== X-Stat-Signature: pta8jky8wh5phxei4z9rdo77zdj7kzk7 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 5C775C0001EA Received-SPF: none (nvidia.com>: No applicable sender policy available) receiver=imf22; identity=mailfrom; envelope-from=""; helo=hqnvemgate24.nvidia.com; client-ip=216.228.121.143 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614838622-733375 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The behaviour of try_to_unmap_one() is difficult to follow because it performs different operations based on a fairly large set of flags used in different combinations. TTU_MUNLOCK is one such flag. However it is exclusively used by try_to_munlock() which specifies no other flags. Therefore rather than overload try_to_unmap_one() with unrelated behaviour split this out into it's own function and remove the flag. Signed-off-by: Alistair Popple Reviewed-by: Ralph Campbell --- Christoph - I didn't add your Reviewed-by because removal of the extra VM_LOCKED check changed things slightly. Let me know if you're still ok for me to add it. Thanks. v4: * Removed redundant check for VM_LOCKED --- include/linux/rmap.h | 1 - mm/rmap.c | 40 ++++++++++++++++++++++++++++++++-------- 2 files changed, 32 insertions(+), 9 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 70085ca1a3fc..7f1ee411bd7b 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -87,7 +87,6 @@ struct anon_vma_chain { enum ttu_flags { TTU_MIGRATION = 0x1, /* migration mode */ - TTU_MUNLOCK = 0x2, /* munlock mode */ TTU_SPLIT_HUGE_PMD = 0x4, /* split huge PMD if any */ TTU_IGNORE_MLOCK = 0x8, /* ignore mlock */ diff --git a/mm/rmap.c b/mm/rmap.c index ef9ef2694c58..c8a637abffb3 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1391,10 +1391,6 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, struct mmu_notifier_range range; enum ttu_flags flags = (enum ttu_flags)(long)arg; - /* munlock has nothing to gain from examining un-locked vmas */ - if ((flags & TTU_MUNLOCK) && !(vma->vm_flags & VM_LOCKED)) - return true; - if (IS_ENABLED(CONFIG_MIGRATION) && (flags & TTU_MIGRATION) && is_zone_device_page(page) && !is_device_private_page(page)) return true; @@ -1455,8 +1451,6 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, page_vma_mapped_walk_done(&pvmw); break; } - if (flags & TTU_MUNLOCK) - continue; } /* Unexpected PMD-mapped THP? */ @@ -1775,6 +1769,37 @@ static int page_not_mapped(struct page *page) return !page_mapped(page); }; +static bool try_to_munlock_one(struct page *page, struct vm_area_struct *vma, + unsigned long address, void *arg) +{ + struct page_vma_mapped_walk pvmw = { + .page = page, + .vma = vma, + .address = address, + }; + + /* munlock has nothing to gain from examining un-locked vmas */ + if (!(vma->vm_flags & VM_LOCKED)) + return true; + + while (page_vma_mapped_walk(&pvmw)) { + /* PTE-mapped THP are never mlocked */ + if (!PageTransCompound(page)) { + /* + * Holding pte lock, we do *not* need + * mmap_lock here + */ + mlock_vma_page(page); + } + page_vma_mapped_walk_done(&pvmw); + + /* found a mlocked page, no point continuing munlock check */ + return false; + } + + return true; +} + /** * try_to_munlock - try to munlock a page * @page: the page to be munlocked @@ -1787,8 +1812,7 @@ static int page_not_mapped(struct page *page) void try_to_munlock(struct page *page) { struct rmap_walk_control rwc = { - .rmap_one = try_to_unmap_one, - .arg = (void *)TTU_MUNLOCK, + .rmap_one = try_to_munlock_one, .done = page_not_mapped, .anon_lock = page_lock_anon_vma_read, From patchwork Thu Mar 4 06:16:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alistair Popple X-Patchwork-Id: 12115529 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2425C433E9 for ; Thu, 4 Mar 2021 06:17:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 797AA64EF6 for ; Thu, 4 Mar 2021 06:17:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 797AA64EF6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1AAD96B000A; Thu, 4 Mar 2021 01:17:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1847B6B000C; Thu, 4 Mar 2021 01:17:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F3D346B000D; Thu, 4 Mar 2021 01:17:07 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id CE0B06B000A for ; Thu, 4 Mar 2021 01:17:07 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 92979181E787C for ; Thu, 4 Mar 2021 06:17:07 +0000 (UTC) X-FDA: 77881184094.26.74BEE53 Received: from hqnvemgate26.nvidia.com (hqnvemgate26.nvidia.com [216.228.121.65]) by imf08.hostedemail.com (Postfix) with ESMTP id 5664F80192DD for ; Thu, 4 Mar 2021 06:17:04 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 03 Mar 2021 22:17:05 -0800 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL105.nvidia.com (172.20.187.12) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:04 +0000 Received: from localhost (172.20.145.6) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:03 +0000 From: Alistair Popple To: , , , CC: , , , , , , , "Alistair Popple" , Christoph Hellwig Subject: [PATCH v4 4/8] mm/rmap: Split migration into its own function Date: Thu, 4 Mar 2021 17:16:41 +1100 Message-ID: <20210304061645.29747-5-apopple@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210304061645.29747-1-apopple@nvidia.com> References: <20210304061645.29747-1-apopple@nvidia.com> MIME-Version: 1.0 X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To DRHQMAIL107.nvidia.com (10.27.9.16) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1614838625; bh=bWAWlWXErFvEXf5u2pRFiHTL5mxzG7rTMT+oz+Hj1bw=; h=From:To:CC:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding:Content-Type: X-Originating-IP:X-ClientProxiedBy; b=gKShrmXHOAOjWLRfuvmj15zH7/KtZFQ1+gAqU9euSX1U/jqCqB/mTgRihVMieSWcM ddakwFhPEJzYUfxDk1+V+TRyYpctfSUuw/p7v+CjrpfpwXF88l4lzQbgJtAObFyIaY /3KLySpG6DI7wCQzKTDT03EoUiso3Yhv4AR0hvCovB182fV/rvXjMRCtgnP5k8FXN7 0ePrff95IquzFcIBEpPl9tILbRVbiUMBZ2THTz3YO58zYSFTkUoAAHopCc7SjWV1NL fhRrpkIWEihrhh47fI8qlJsotrCqODg73UJ5rJyEYFmULusyRoa37rkYBxjUIPOAkj YVGvECGr6K++g== X-Stat-Signature: tn9h9mgnjy9aeet5tn91xjd3peanz1yn X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 5664F80192DD Received-SPF: none (nvidia.com>: No applicable sender policy available) receiver=imf08; identity=mailfrom; envelope-from=""; helo=hqnvemgate26.nvidia.com; client-ip=216.228.121.65 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614838624-917499 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Migration is currently implemented as a mode of operation for try_to_unmap_one() generally specified by passing the TTU_MIGRATION flag or in the case of splitting a huge anonymous page TTU_SPLIT_FREEZE. However it does not have much in common with the rest of the unmap functionality of try_to_unmap_one() and thus splitting it into a separate function reduces the complexity of try_to_unmap_one() making it more readable. Several simplifications can also be made in try_to_migrate_one() based on the following observations: - All users of TTU_MIGRATION also set TTU_IGNORE_MLOCK. - No users of TTU_MIGRATION ever set TTU_IGNORE_HWPOISON. - No users of TTU_MIGRATION ever set TTU_BATCH_FLUSH. TTU_SPLIT_FREEZE is a special case of migration used when splitting an anonymous page. This is most easily dealt with by calling the correct function from unmap_page() in mm/huge_memory.c - either try_to_migrate() for PageAnon or try_to_unmap(). Signed-off-by: Alistair Popple Reviewed-by: Christoph Hellwig Reviewed-by: Ralph Campbell --- include/linux/rmap.h | 4 +- mm/huge_memory.c | 10 +- mm/migrate.c | 9 +- mm/rmap.c | 352 +++++++++++++++++++++++++++++++------------ 4 files changed, 269 insertions(+), 106 deletions(-) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 7f1ee411bd7b..77fa17de51d7 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -86,8 +86,6 @@ struct anon_vma_chain { }; enum ttu_flags { - TTU_MIGRATION = 0x1, /* migration mode */ - TTU_SPLIT_HUGE_PMD = 0x4, /* split huge PMD if any */ TTU_IGNORE_MLOCK = 0x8, /* ignore mlock */ TTU_IGNORE_HWPOISON = 0x20, /* corrupted page is recoverable */ @@ -96,7 +94,6 @@ enum ttu_flags { * do a final flush if necessary */ TTU_RMAP_LOCKED = 0x80, /* do not grab rmap lock: * caller holds it */ - TTU_SPLIT_FREEZE = 0x100, /* freeze pte under splitting thp */ }; #ifdef CONFIG_MMU @@ -193,6 +190,7 @@ static inline void page_dup_rmap(struct page *page, bool compound) int page_referenced(struct page *, int is_locked, struct mem_cgroup *memcg, unsigned long *vm_flags); +bool try_to_migrate(struct page *page, enum ttu_flags flags); bool try_to_unmap(struct page *, enum ttu_flags flags); /* Avoid racy checks */ diff --git a/mm/huge_memory.c b/mm/huge_memory.c index cb3bc9d3ed3a..4589b483c99e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2351,16 +2351,16 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma, static void unmap_page(struct page *page) { - enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | - TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; + enum ttu_flags ttu_flags = TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; bool unmap_success; VM_BUG_ON_PAGE(!PageHead(page), page); if (PageAnon(page)) - ttu_flags |= TTU_SPLIT_FREEZE; - - unmap_success = try_to_unmap(page, ttu_flags); + unmap_success = try_to_migrate(page, ttu_flags); + else + unmap_success = try_to_unmap(page, ttu_flags | + TTU_IGNORE_MLOCK); VM_BUG_ON_PAGE(!unmap_success, page); } diff --git a/mm/migrate.c b/mm/migrate.c index 30c18e7c6089..bea67789a5b2 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1124,7 +1124,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, /* Establish migration ptes */ VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma, page); - try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK); + try_to_migrate(page, 0); page_was_mapped = 1; } @@ -1326,7 +1326,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, if (page_mapped(hpage)) { bool mapping_locked = false; - enum ttu_flags ttu = TTU_MIGRATION|TTU_IGNORE_MLOCK; + enum ttu_flags ttu = 0; if (!PageAnon(hpage)) { /* @@ -1343,7 +1343,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, ttu |= TTU_RMAP_LOCKED; } - try_to_unmap(hpage, ttu); + try_to_migrate(hpage, ttu); page_was_mapped = 1; if (mapping_locked) @@ -2750,7 +2750,6 @@ static void migrate_vma_prepare(struct migrate_vma *migrate) */ static void migrate_vma_unmap(struct migrate_vma *migrate) { - int flags = TTU_MIGRATION | TTU_IGNORE_MLOCK; const unsigned long npages = migrate->npages; const unsigned long start = migrate->start; unsigned long addr, i, restore = 0; @@ -2762,7 +2761,7 @@ static void migrate_vma_unmap(struct migrate_vma *migrate) continue; if (page_mapped(page)) { - try_to_unmap(page, flags); + try_to_migrate(page, 0); if (page_mapped(page)) goto restore; } diff --git a/mm/rmap.c b/mm/rmap.c index c8a637abffb3..15c012d30f05 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1391,14 +1391,8 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, struct mmu_notifier_range range; enum ttu_flags flags = (enum ttu_flags)(long)arg; - if (IS_ENABLED(CONFIG_MIGRATION) && (flags & TTU_MIGRATION) && - is_zone_device_page(page) && !is_device_private_page(page)) - return true; - - if (flags & TTU_SPLIT_HUGE_PMD) { - split_huge_pmd_address(vma, address, - flags & TTU_SPLIT_FREEZE, page); - } + if (flags & TTU_SPLIT_HUGE_PMD) + split_huge_pmd_address(vma, address, false, page); /* * For THP, we have to assume the worse case ie pmd for invalidation. @@ -1422,16 +1416,6 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, mmu_notifier_invalidate_range_start(&range); while (page_vma_mapped_walk(&pvmw)) { -#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION - /* PMD-mapped THP migration entry */ - if (!pvmw.pte && (flags & TTU_MIGRATION)) { - VM_BUG_ON_PAGE(PageHuge(page) || !PageTransCompound(page), page); - - set_pmd_migration_entry(&pvmw, page); - continue; - } -#endif - /* * If the page is mlock()d, we cannot swap it out. * If it's recently referenced (perhaps page_referenced @@ -1493,46 +1477,6 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, } } - if (IS_ENABLED(CONFIG_MIGRATION) && - (flags & TTU_MIGRATION) && - is_zone_device_page(page)) { - swp_entry_t entry; - pte_t swp_pte; - - pteval = ptep_get_and_clear(mm, pvmw.address, pvmw.pte); - - /* - * Store the pfn of the page in a special migration - * pte. do_swap_page() will wait until the migration - * pte is removed and then restart fault handling. - */ - entry = make_readable_migration_entry(page_to_pfn(page)); - swp_pte = swp_entry_to_pte(entry); - - /* - * pteval maps a zone device page and is therefore - * a swap pte. - */ - if (pte_swp_soft_dirty(pteval)) - swp_pte = pte_swp_mksoft_dirty(swp_pte); - if (pte_swp_uffd_wp(pteval)) - swp_pte = pte_swp_mkuffd_wp(swp_pte); - set_pte_at(mm, pvmw.address, pvmw.pte, swp_pte); - /* - * No need to invalidate here it will synchronize on - * against the special swap migration pte. - * - * The assignment to subpage above was computed from a - * swap PTE which results in an invalid pointer. - * Since only PAGE_SIZE pages can currently be - * migrated, just set it to page. This will need to be - * changed when hugepage migrations to device private - * memory are supported. - */ - subpage = page; - goto discard; - } - /* Nuke the page table entry. */ flush_cache_page(vma, address, pte_pfn(*pvmw.pte)); if (should_defer_flush(mm, flags)) { @@ -1585,39 +1529,6 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, /* We have to invalidate as we cleared the pte */ mmu_notifier_invalidate_range(mm, address, address + PAGE_SIZE); - } else if (IS_ENABLED(CONFIG_MIGRATION) && - (flags & (TTU_MIGRATION|TTU_SPLIT_FREEZE))) { - swp_entry_t entry; - pte_t swp_pte; - - if (arch_unmap_one(mm, vma, address, pteval) < 0) { - set_pte_at(mm, address, pvmw.pte, pteval); - ret = false; - page_vma_mapped_walk_done(&pvmw); - break; - } - - /* - * Store the pfn of the page in a special migration - * pte. do_swap_page() will wait until the migration - * pte is removed and then restart fault handling. - */ - if (pte_write(pteval)) - entry = make_writable_migration_entry( - page_to_pfn(subpage)); - else - entry = make_readable_migration_entry( - page_to_pfn(subpage)); - swp_pte = swp_entry_to_pte(entry); - if (pte_soft_dirty(pteval)) - swp_pte = pte_swp_mksoft_dirty(swp_pte); - if (pte_uffd_wp(pteval)) - swp_pte = pte_swp_mkuffd_wp(swp_pte); - set_pte_at(mm, address, pvmw.pte, swp_pte); - /* - * No need to invalidate here it will synchronize on - * against the special swap migration pte. - */ } else if (PageAnon(page)) { swp_entry_t entry = { .val = page_private(subpage) }; pte_t swp_pte; @@ -1744,6 +1655,262 @@ bool try_to_unmap(struct page *page, enum ttu_flags flags) .anon_lock = page_lock_anon_vma_read, }; + if (flags & TTU_RMAP_LOCKED) + rmap_walk_locked(page, &rwc); + else + rmap_walk(page, &rwc); + + return !page_mapcount(page) ? true : false; +} + +/* + * @arg: enum ttu_flags will be passed to this argument + */ +static bool try_to_migrate_one(struct page *page, struct vm_area_struct *vma, + unsigned long address, void *arg) +{ + struct mm_struct *mm = vma->vm_mm; + struct page_vma_mapped_walk pvmw = { + .page = page, + .vma = vma, + .address = address, + }; + pte_t pteval; + struct page *subpage; + bool ret = true; + struct mmu_notifier_range range; + enum ttu_flags flags = (enum ttu_flags)(long)arg; + + if (is_zone_device_page(page) && !is_device_private_page(page)) + return true; + + /* + * unmap_page() in mm/huge_memory.c is the only user of migration with + * TTU_SPLIT_HUGE_PMD and it wants to freeze. + */ + if (flags & TTU_SPLIT_HUGE_PMD) + split_huge_pmd_address(vma, address, true, page); + + /* + * For THP, we have to assume the worse case ie pmd for invalidation. + * For hugetlb, it could be much worse if we need to do pud + * invalidation in the case of pmd sharing. + * + * Note that the page can not be free in this function as call of + * try_to_unmap() must hold a reference on the page. + */ + mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, + address, + min(vma->vm_end, address + page_size(page))); + if (PageHuge(page)) { + /* + * If sharing is possible, start and end will be adjusted + * accordingly. + */ + adjust_range_if_pmd_sharing_possible(vma, &range.start, + &range.end); + } + mmu_notifier_invalidate_range_start(&range); + + while (page_vma_mapped_walk(&pvmw)) { +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION + /* PMD-mapped THP migration entry */ + if (!pvmw.pte) { + VM_BUG_ON_PAGE(PageHuge(page) || + !PageTransCompound(page), page); + + set_pmd_migration_entry(&pvmw, page); + continue; + } +#endif + + /* Unexpected PMD-mapped THP? */ + VM_BUG_ON_PAGE(!pvmw.pte, page); + + subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte); + address = pvmw.address; + + if (PageHuge(page) && !PageAnon(page)) { + /* + * To call huge_pmd_unshare, i_mmap_rwsem must be + * held in write mode. Caller needs to explicitly + * do this outside rmap routines. + */ + VM_BUG_ON(!(flags & TTU_RMAP_LOCKED)); + if (huge_pmd_unshare(mm, vma, &address, pvmw.pte)) { + /* + * huge_pmd_unshare unmapped an entire PMD + * page. There is no way of knowing exactly + * which PMDs may be cached for this mm, so + * we must flush them all. start/end were + * already adjusted above to cover this range. + */ + flush_cache_range(vma, range.start, range.end); + flush_tlb_range(vma, range.start, range.end); + mmu_notifier_invalidate_range(mm, range.start, + range.end); + + /* + * The ref count of the PMD page was dropped + * which is part of the way map counting + * is done for shared PMDs. Return 'true' + * here. When there is no other sharing, + * huge_pmd_unshare returns false and we will + * unmap the actual page and drop map count + * to zero. + */ + page_vma_mapped_walk_done(&pvmw); + break; + } + } + + /* Nuke the page table entry. */ + flush_cache_page(vma, address, pte_pfn(*pvmw.pte)); + pteval = ptep_clear_flush(vma, address, pvmw.pte); + + /* Move the dirty bit to the page. Now the pte is gone. */ + if (pte_dirty(pteval)) + set_page_dirty(page); + + /* Update high watermark before we lower rss */ + update_hiwater_rss(mm); + + if (is_zone_device_page(page)) { + swp_entry_t entry; + pte_t swp_pte; + + /* + * Store the pfn of the page in a special migration + * pte. do_swap_page() will wait until the migration + * pte is removed and then restart fault handling. + */ + entry = make_readable_migration_entry( + page_to_pfn(page)); + swp_pte = swp_entry_to_pte(entry); + + /* + * pteval maps a zone device page and is therefore + * a swap pte. + */ + if (pte_swp_soft_dirty(pteval)) + swp_pte = pte_swp_mksoft_dirty(swp_pte); + if (pte_swp_uffd_wp(pteval)) + swp_pte = pte_swp_mkuffd_wp(swp_pte); + set_pte_at(mm, pvmw.address, pvmw.pte, swp_pte); + /* + * No need to invalidate here it will synchronize on + * against the special swap migration pte. + * + * The assignment to subpage above was computed from a + * swap PTE which results in an invalid pointer. + * Since only PAGE_SIZE pages can currently be + * migrated, just set it to page. This will need to be + * changed when hugepage migrations to device private + * memory are supported. + */ + subpage = page; + } else if (PageHWPoison(page)) { + pteval = swp_entry_to_pte(make_hwpoison_entry(subpage)); + if (PageHuge(page)) { + hugetlb_count_sub(compound_nr(page), mm); + set_huge_swap_pte_at(mm, address, + pvmw.pte, pteval, + vma_mmu_pagesize(vma)); + } else { + dec_mm_counter(mm, mm_counter(page)); + set_pte_at(mm, address, pvmw.pte, pteval); + } + + } else if (pte_unused(pteval) && !userfaultfd_armed(vma)) { + /* + * The guest indicated that the page content is of no + * interest anymore. Simply discard the pte, vmscan + * will take care of the rest. + * A future reference will then fault in a new zero + * page. When userfaultfd is active, we must not drop + * this page though, as its main user (postcopy + * migration) will not expect userfaults on already + * copied pages. + */ + dec_mm_counter(mm, mm_counter(page)); + /* We have to invalidate as we cleared the pte */ + mmu_notifier_invalidate_range(mm, address, + address + PAGE_SIZE); + } else { + swp_entry_t entry; + pte_t swp_pte; + + if (arch_unmap_one(mm, vma, address, pteval) < 0) { + set_pte_at(mm, address, pvmw.pte, pteval); + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } + + /* + * Store the pfn of the page in a special migration + * pte. do_swap_page() will wait until the migration + * pte is removed and then restart fault handling. + */ + if (pte_write(pteval)) + entry = make_writable_migration_entry( + page_to_pfn(subpage)); + else + entry = make_readable_migration_entry( + page_to_pfn(subpage)); + + swp_pte = swp_entry_to_pte(entry); + if (pte_soft_dirty(pteval)) + swp_pte = pte_swp_mksoft_dirty(swp_pte); + if (pte_uffd_wp(pteval)) + swp_pte = pte_swp_mkuffd_wp(swp_pte); + set_pte_at(mm, address, pvmw.pte, swp_pte); + /* + * No need to invalidate here it will synchronize on + * against the special swap migration pte. + */ + } + + /* + * No need to call mmu_notifier_invalidate_range() it has be + * done above for all cases requiring it to happen under page + * table lock before mmu_notifier_invalidate_range_end() + * + * See Documentation/vm/mmu_notifier.rst + */ + page_remove_rmap(subpage, PageHuge(page)); + put_page(page); + } + + mmu_notifier_invalidate_range_end(&range); + + return ret; +} + +/** + * try_to_migrate - try to replace all page table mappings with swap entries + * @page: the page to replace page table entries for + * @flags: action and flags + * + * Tries to remove all the page table entries which are mapping this page and + * replace them with special swap entries. Caller must hold the page lock. + * + * If is successful, return true. Otherwise, false. + */ +bool try_to_migrate(struct page *page, enum ttu_flags flags) +{ + struct rmap_walk_control rwc = { + .rmap_one = try_to_migrate_one, + .arg = (void *)flags, + .done = page_mapcount_is_zero, + .anon_lock = page_lock_anon_vma_read, + }; + + /* Migration always ignores mlock */ + if (WARN_ON_ONCE((flags & TTU_IGNORE_MLOCK)) || + WARN_ON_ONCE(flags & TTU_BATCH_FLUSH)) + return false; + /* * During exec, a temporary VMA is setup and later moved. * The VMA is moved under the anon_vma lock but not the @@ -1752,8 +1919,7 @@ bool try_to_unmap(struct page *page, enum ttu_flags flags) * locking requirements of exec(), migration skips * temporary VMAs until after exec() completes. */ - if ((flags & (TTU_MIGRATION|TTU_SPLIT_FREEZE)) - && !PageKsm(page) && PageAnon(page)) + if (!PageKsm(page) && PageAnon(page)) rwc.invalid_vma = invalid_migration_vma; if (flags & TTU_RMAP_LOCKED) From patchwork Thu Mar 4 06:16:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alistair Popple X-Patchwork-Id: 12115531 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BB3EC433DB for ; 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Thu, 4 Mar 2021 06:17:10 +0000 (UTC) X-FDA: 77881184220.08.37AB5CE Received: from hqnvemgate25.nvidia.com (hqnvemgate25.nvidia.com [216.228.121.64]) by imf18.hostedemail.com (Postfix) with ESMTP id A79002000391 for ; Thu, 4 Mar 2021 06:17:09 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 03 Mar 2021 22:17:08 -0800 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:08 +0000 Received: from localhost (172.20.145.6) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:07 +0000 From: Alistair Popple To: , , , CC: , , , , , , , "Alistair Popple" Subject: [PATCH v4 5/8] mm: Device exclusive memory access Date: Thu, 4 Mar 2021 17:16:42 +1100 Message-ID: <20210304061645.29747-6-apopple@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210304061645.29747-1-apopple@nvidia.com> References: <20210304061645.29747-1-apopple@nvidia.com> MIME-Version: 1.0 X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To DRHQMAIL107.nvidia.com (10.27.9.16) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1614838628; bh=hoEvOaAOVjWfFhzIIbnfE7wLP3jmU1Vny5LtVXS0MWc=; h=From:To:CC:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding:Content-Type: X-Originating-IP:X-ClientProxiedBy; b=m3B8Qhhx8JhLS5yNN9mT3PdaAinF8Tg4hfgTzAbW9q/zouemQcqE8jCNhmnfStP6L HUXPvIqEYZKZ9MlvqNyDRHIGk0y9J+oasj9gz2SdWxd/KSMmfYfq/2CbnEpgvLnf3Z +BS7+TgLrfpjO8U4GSpYrNtNuhn6jrjryixFhDPVhx0OLNOLrXsBE1ppDM29jANgah ijZr/UxyKbXSAli14odvEe7CwGpnkapkuKjuFFo1rFputhsAlRgxiyUztBDRTcyq+X 37wZGhZCJ1qfTTyNtU9jAUzadi8MbSGPMViE4EzuIr1y/26vqkd9GBOtFQ5aisFtaQ ynXjqtqI27T2w== X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: A79002000391 X-Stat-Signature: odzwmqqd88dumkgfgcyu7e6e9eznd7jq Received-SPF: none (nvidia.com>: No applicable sender policy available) receiver=imf18; identity=mailfrom; envelope-from=""; helo=hqnvemgate25.nvidia.com; client-ip=216.228.121.64 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614838629-589049 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Some devices require exclusive write access to shared virtual memory (SVM) ranges to perform atomic operations on that memory. This requires CPU page tables to be updated to deny access whilst atomic operations are occurring. In order to do this introduce a new swap entry type (SWP_DEVICE_EXCLUSIVE). When a SVM range needs to be marked for exclusive access by a device all page table mappings for the particular range are replaced with device exclusive swap entries. This causes any CPU access to the page to result in a fault. Faults are resovled by replacing the faulting entry with the original mapping. This results in MMU notifiers being called which a driver uses to update access permissions such as revoking atomic access. After notifiers have been called the device will no longer have exclusive access to the region. Signed-off-by: Alistair Popple --- v4: * Add function to check that mappings are still valid and exclusive. * s/long/unsigned long/ in make_device_exclusive_entry(). --- Documentation/vm/hmm.rst | 15 +++ include/linux/rmap.h | 5 + include/linux/swap.h | 4 +- include/linux/swapops.h | 44 +++++++- mm/hmm.c | 5 + mm/memory.c | 107 +++++++++++++++++- mm/mprotect.c | 8 ++ mm/page_vma_mapped.c | 9 +- mm/rmap.c | 230 +++++++++++++++++++++++++++++++++++++++ 9 files changed, 420 insertions(+), 7 deletions(-) diff --git a/Documentation/vm/hmm.rst b/Documentation/vm/hmm.rst index 09e28507f5b2..f526ac4d8798 100644 --- a/Documentation/vm/hmm.rst +++ b/Documentation/vm/hmm.rst @@ -405,6 +405,21 @@ between device driver specific code and shared common code: The lock can now be released. +Exclusive access memory +======================= + +Not all devices support atomic access to system memory. To support atomic +operations to a shared virtual memory page such a device needs access to that +page which is exclusive of any userspace access from the CPU. The +``make_device_exclusive_range()`` function can be used to make a memory range +inaccessible from userspace. + +This replaces all mappings for pages in the given range with special swap +entries. Any attempt to access the swap entry results in a fault which is +resovled by replacing the entry with the original mapping. A driver gets +notified that the mapping has been changed by MMU notifiers, after which point +it will no longer have exclusive access to the page. + Memory cgroup (memcg) and rss accounting ======================================== diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 77fa17de51d7..93cbb88f7253 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -193,6 +193,11 @@ int page_referenced(struct page *, int is_locked, bool try_to_migrate(struct page *page, enum ttu_flags flags); bool try_to_unmap(struct page *, enum ttu_flags flags); +int make_device_exclusive_range(struct mm_struct *mm, unsigned long start, + unsigned long end, struct page **pages); +bool check_device_exclusive_range(struct mm_struct *mm, unsigned long start, + unsigned long end, struct page **pages); + /* Avoid racy checks */ #define PVMW_SYNC (1 << 0) /* Look for migarion entries rather than present PTEs */ diff --git a/include/linux/swap.h b/include/linux/swap.h index 57a7690966a4..2d8b8e7fb4c2 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -63,9 +63,11 @@ static inline int current_is_kswapd(void) * to a special SWP_DEVICE_* entry. */ #ifdef CONFIG_DEVICE_PRIVATE -#define SWP_DEVICE_NUM 2 +#define SWP_DEVICE_NUM 4 #define SWP_DEVICE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM) #define SWP_DEVICE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+1) +#define SWP_DEVICE_EXCLUSIVE_WRITE (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+2) +#define SWP_DEVICE_EXCLUSIVE_READ (MAX_SWAPFILES+SWP_HWPOISON_NUM+SWP_MIGRATION_NUM+3) #else #define SWP_DEVICE_NUM 0 #endif diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 81008b0179cc..20b726e27f37 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -120,6 +120,27 @@ static inline bool is_writable_device_private_entry(swp_entry_t entry) { return unlikely(swp_type(entry) == SWP_DEVICE_WRITE); } + +static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset) +{ + return swp_entry(SWP_DEVICE_EXCLUSIVE_READ, offset); +} + +static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset) +{ + return swp_entry(SWP_DEVICE_EXCLUSIVE_WRITE, offset); +} + +static inline bool is_device_exclusive_entry(swp_entry_t entry) +{ + return swp_type(entry) == SWP_DEVICE_EXCLUSIVE_READ || + swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE; +} + +static inline bool is_writable_device_exclusive_entry(swp_entry_t entry) +{ + return unlikely(swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE); +} #else /* CONFIG_DEVICE_PRIVATE */ static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset) { @@ -140,6 +161,26 @@ static inline bool is_writable_device_private_entry(swp_entry_t entry) { return false; } + +static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset) +{ + return swp_entry(0, 0); +} + +static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset) +{ + return swp_entry(0, 0); +} + +static inline bool is_device_exclusive_entry(swp_entry_t entry) +{ + return false; +} + +static inline bool is_writable_device_exclusive_entry(swp_entry_t entry) +{ + return false; +} #endif /* CONFIG_DEVICE_PRIVATE */ #ifdef CONFIG_MIGRATION @@ -219,7 +260,8 @@ static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry) */ static inline bool is_pfn_swap_entry(swp_entry_t entry) { - return is_migration_entry(entry) || is_device_private_entry(entry); + return is_migration_entry(entry) || is_device_private_entry(entry) || + is_device_exclusive_entry(entry); } struct page_vma_mapped_walk; diff --git a/mm/hmm.c b/mm/hmm.c index 11df3ca30b82..fad6be2bf072 100644 --- a/mm/hmm.c +++ b/mm/hmm.c @@ -26,6 +26,8 @@ #include #include +#include "internal.h" + struct hmm_vma_walk { struct hmm_range *range; unsigned long last; @@ -271,6 +273,9 @@ static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, if (!non_swap_entry(entry)) goto fault; + if (is_device_exclusive_entry(entry)) + goto fault; + if (is_migration_entry(entry)) { pte_unmap(ptep); hmm_vma_walk->last = addr; diff --git a/mm/memory.c b/mm/memory.c index 957e00525a9a..7ad201710a35 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -769,6 +769,27 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, pte = pte_swp_mkuffd_wp(pte); set_pte_at(src_mm, addr, src_pte, pte); } + } else if (is_device_exclusive_entry(entry)) { + page = pfn_swap_entry_to_page(entry); + + get_page(page); + rss[mm_counter(page)]++; + + if (is_writable_device_exclusive_entry(entry) && + is_cow_mapping(vm_flags)) { + /* + * COW mappings require pages in both + * parent and child to be set to read. + */ + entry = make_readable_device_exclusive_entry( + swp_offset(entry)); + pte = swp_entry_to_pte(entry); + if (pte_swp_soft_dirty(*src_pte)) + pte = pte_swp_mksoft_dirty(pte); + if (pte_swp_uffd_wp(*src_pte)) + pte = pte_swp_mkuffd_wp(pte); + set_pte_at(src_mm, addr, src_pte, pte); + } } set_pte_at(dst_mm, addr, dst_pte, pte); return 0; @@ -1275,7 +1296,8 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, } entry = pte_to_swp_entry(ptent); - if (is_device_private_entry(entry)) { + if (is_device_private_entry(entry) || + is_device_exclusive_entry(entry)) { struct page *page = pfn_swap_entry_to_page(entry); if (unlikely(details && details->check_mapping)) { @@ -1291,7 +1313,10 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); rss[mm_counter(page)]--; - page_remove_rmap(page, false); + + if (is_device_private_entry(entry)) + page_remove_rmap(page, false); + put_page(page); continue; } @@ -3245,6 +3270,81 @@ void unmap_mapping_range(struct address_space *mapping, } EXPORT_SYMBOL(unmap_mapping_range); +static void restore_exclusive_pte(struct vm_area_struct *vma, + struct page *page, unsigned long address, + pte_t *ptep) +{ + pte_t pte; + swp_entry_t entry; + + pte = pte_mkold(mk_pte(page, READ_ONCE(vma->vm_page_prot))); + if (pte_swp_soft_dirty(*ptep)) + pte = pte_mksoft_dirty(pte); + + entry = pte_to_swp_entry(*ptep); + if (pte_swp_uffd_wp(*ptep)) + pte = pte_mkuffd_wp(pte); + else if (is_writable_device_exclusive_entry(entry)) + pte = maybe_mkwrite(pte_mkdirty(pte), vma); + + set_pte_at(vma->vm_mm, address, ptep, pte); + + /* + * No need to take a page reference as one was already + * created when the swap entry was made. + */ + if (PageAnon(page)) + page_add_anon_rmap(page, vma, address, false); + else + page_add_file_rmap(page, false); + + if (vma->vm_flags & VM_LOCKED) + mlock_vma_page(page); + + /* + * No need to invalidate - it was non-present before. However + * secondary CPUs may have mappings that need invalidating. + */ + update_mmu_cache(vma, address, ptep); +} + +/* + * Restore a potential device exclusive pte to a working pte entry + */ +static vm_fault_t remove_device_exclusive_entry(struct vm_fault *vmf) +{ + struct page *page = vmf->page; + struct vm_area_struct *vma = vmf->vma; + struct page_vma_mapped_walk pvmw = { + .page = page, + .vma = vma, + .address = vmf->address, + .flags = PVMW_SYNC, + }; + vm_fault_t ret = 0; + struct mmu_notifier_range range; + + lock_page(page); + mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, + vmf->address & PAGE_MASK, + (vmf->address & PAGE_MASK) + PAGE_SIZE); + mmu_notifier_invalidate_range_start(&range); + + while (page_vma_mapped_walk(&pvmw)) { + if (unlikely(!pte_same(*pvmw.pte, vmf->orig_pte))) { + page_vma_mapped_walk_done(&pvmw); + break; + } + + restore_exclusive_pte(vma, page, pvmw.address, pvmw.pte); + } + + unlock_page(page); + + mmu_notifier_invalidate_range_end(&range); + return ret; +} + /* * We enter with non-exclusive mmap_lock (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. @@ -3272,6 +3372,9 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) if (is_migration_entry(entry)) { migration_entry_wait(vma->vm_mm, vmf->pmd, vmf->address); + } else if (is_device_exclusive_entry(entry)) { + vmf->page = pfn_swap_entry_to_page(entry); + ret = remove_device_exclusive_entry(vmf); } else if (is_device_private_entry(entry)) { vmf->page = pfn_swap_entry_to_page(entry); ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); diff --git a/mm/mprotect.c b/mm/mprotect.c index a6c757d87789..fc4a7622497f 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -165,6 +165,14 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, newpte = swp_entry_to_pte(entry); if (pte_swp_uffd_wp(oldpte)) newpte = pte_swp_mkuffd_wp(newpte); + } else if (is_writable_device_exclusive_entry(entry)) { + entry = make_readable_device_exclusive_entry( + swp_offset(entry)); + newpte = swp_entry_to_pte(entry); + if (pte_swp_soft_dirty(oldpte)) + newpte = pte_swp_mksoft_dirty(newpte); + if (pte_swp_uffd_wp(oldpte)) + newpte = pte_swp_mkuffd_wp(newpte); } else { newpte = oldpte; } diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index eed988ab2e81..29842f169219 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -41,7 +41,8 @@ static bool map_pte(struct page_vma_mapped_walk *pvmw) /* Handle un-addressable ZONE_DEVICE memory */ entry = pte_to_swp_entry(*pvmw->pte); - if (!is_device_private_entry(entry)) + if (!is_device_private_entry(entry) && + !is_device_exclusive_entry(entry)) return false; } else if (!pte_present(*pvmw->pte)) return false; @@ -93,7 +94,8 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw) return false; entry = pte_to_swp_entry(*pvmw->pte); - if (!is_migration_entry(entry)) + if (!is_migration_entry(entry) && + !is_device_exclusive_entry(entry)) return false; pfn = swp_offset(entry); @@ -102,7 +104,8 @@ static bool check_pte(struct page_vma_mapped_walk *pvmw) /* Handle un-addressable ZONE_DEVICE memory */ entry = pte_to_swp_entry(*pvmw->pte); - if (!is_device_private_entry(entry)) + if (!is_device_private_entry(entry) && + !is_device_exclusive_entry(entry)) return false; pfn = swp_offset(entry); diff --git a/mm/rmap.c b/mm/rmap.c index 15c012d30f05..dbab4ec70c2a 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1990,6 +1990,236 @@ void try_to_munlock(struct page *page) rmap_walk(page, &rwc); } +static bool try_to_protect_one(struct page *page, struct vm_area_struct *vma, + unsigned long address, void *arg) +{ + struct mm_struct *mm = vma->vm_mm; + struct page_vma_mapped_walk pvmw = { + .page = page, + .vma = vma, + .address = address, + }; + pte_t pteval; + struct page *subpage; + bool ret = true; + struct mmu_notifier_range range; + swp_entry_t entry; + pte_t swp_pte; + + mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, + address, + min(vma->vm_end, address + page_size(page))); + if (PageHuge(page)) { + /* + * If sharing is possible, start and end will be adjusted + * accordingly. + */ + adjust_range_if_pmd_sharing_possible(vma, &range.start, + &range.end); + } + mmu_notifier_invalidate_range_start(&range); + + while (page_vma_mapped_walk(&pvmw)) { + /* Unexpected PMD-mapped THP? */ + VM_BUG_ON_PAGE(!pvmw.pte, page); + + if (!pte_present(*pvmw.pte)) { + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } + + subpage = page - page_to_pfn(page) + pte_pfn(*pvmw.pte); + address = pvmw.address; + + /* Nuke the page table entry. */ + flush_cache_page(vma, address, pte_pfn(*pvmw.pte)); + pteval = ptep_clear_flush(vma, address, pvmw.pte); + + /* Move the dirty bit to the page. Now the pte is gone. */ + if (pte_dirty(pteval)) + set_page_dirty(page); + + /* Update high watermark before we lower rss */ + update_hiwater_rss(mm); + + if (arch_unmap_one(mm, vma, address, pteval) < 0) { + set_pte_at(mm, address, pvmw.pte, pteval); + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } + + /* + * Store the pfn of the page in a special migration + * pte. do_swap_page() will wait until the migration + * pte is removed and then restart fault handling. + */ + if (pte_write(pteval)) + entry = make_writable_device_exclusive_entry( + page_to_pfn(subpage)); + else + entry = make_readable_device_exclusive_entry( + page_to_pfn(subpage)); + swp_pte = swp_entry_to_pte(entry); + if (pte_soft_dirty(pteval)) + swp_pte = pte_swp_mksoft_dirty(swp_pte); + if (pte_uffd_wp(pteval)) + swp_pte = pte_swp_mkuffd_wp(swp_pte); + + /* Take a reference for the swap entry */ + get_page(page); + set_pte_at(mm, address, pvmw.pte, swp_pte); + + page_remove_rmap(subpage, PageHuge(page)); + put_page(page); + } + + mmu_notifier_invalidate_range_end(&range); + + return ret; +} + +/** + * try_to_protect - try to replace all page table mappings with swap entries + * @page: the page to replace page table entries for + * @flags: action and flags + * + * Tries to remove all the page table entries which are mapping this page and + * replace them with special swap entries to grant a device exclusive access to + * the page. Caller must hold the page lock. + * + * If is successful, return true. Otherwise, false. + */ +static bool try_to_protect(struct page *page) +{ + struct rmap_walk_control rwc = { + .rmap_one = try_to_protect_one, + .done = page_mapcount_is_zero, + .anon_lock = page_lock_anon_vma_read, + }; + + /* + * During exec, a temporary VMA is setup and later moved. + * The VMA is moved under the anon_vma lock but not the + * page tables leading to a race where migration cannot + * find the migration ptes. Rather than increasing the + * locking requirements of exec(), migration skips + * temporary VMAs until after exec() completes. + */ + if (!PageKsm(page) && PageAnon(page)) + rwc.invalid_vma = invalid_migration_vma; + + rmap_walk(page, &rwc); + + return !page_mapcount(page) ? true : false; +} + +/** + * make_device_exclusive_range() - Mark a range for exclusive use by a device + * @mm: mm_struct of assoicated target process + * @start: start of the region to mark for exclusive device access + * @end: end address of region + * @pages: returns the pages which were successfully marked for exclusive access + * + * Returns: number of pages successfully marked for exclusive access + * + * This function finds ptes mapping page(s) to the given address range, locks + * them and replaces mappings with special swap entries preventing userspace CPU + * access. On fault these entries are replaced with the original mapping after + * calling MMU notifiers. + * + * A driver using this to program access from a device must use + * check_device_exclusive_range() under a mmu notifier critical section to hold + * a device specific lock during programming. Once programming is complete it + * should drop the page lock and reference. + */ +int make_device_exclusive_range(struct mm_struct *mm, unsigned long start, + unsigned long end, struct page **pages) +{ + unsigned long npages = (end - start) >> PAGE_SHIFT; + unsigned long i; + + npages = get_user_pages_remote(mm, start, npages, + FOLL_GET | FOLL_WRITE | FOLL_SPLIT_PMD, + pages, NULL, NULL); + for (i = 0; i < npages; i++, start += PAGE_SIZE) { + if (!trylock_page(pages[i])) { + put_page(pages[i]); + pages[i] = NULL; + continue; + } + + if (!try_to_protect(pages[i])) { + unlock_page(pages[i]); + put_page(pages[i]); + pages[i] = NULL; + } + } + + return npages; +} +EXPORT_SYMBOL_GPL(make_device_exclusive_range); + +/** + * check_device_exclusive_range() - Check a range is marked for exclusive use + * @mm: mm_struct of assoicated target process + * @start: start of the region to mark for exclusive device access + * @end: end address of region + * @pages: pages to check + * + * Returns: True if all pages are still mapped writable for exclusive use. + * + * Callers must use this to check the page is still mapped writable for + * exclusive use before programming any device access. This function does not + * take the PTL so callers must use a mmu interval notifier critical section for + * synchronisation. + */ +bool check_device_exclusive_range(struct mm_struct *mm, unsigned long start, + unsigned long end, struct page **pages) +{ + unsigned long address, i; + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + pte_t *ptep; + pte_t pte; + + for (address = start, i = 0; + address < end; + address += PAGE_SIZE, i++) { + pgd = pgd_offset(mm, address); + if (!pgd_present(*pgd)) + return false; + p4d = p4d_offset(pgd, address); + if (p4d_none(*p4d)) + return false; + pud = pud_offset(p4d, address); + if (pud_none(*pud)) + return false; + pmd = pmd_offset(pud, address); + if (!pmd_present(*pmd) || pmd_huge(*pmd)) + return false; + ptep = pte_offset_map(pmd, address); + pte = ptep_get(ptep); + pte_unmap(pte); + if (is_swap_pte(pte)) { + swp_entry_t entry = pte_to_swp_entry(pte); + + if (!is_writable_device_exclusive_entry(entry)) + return false; + + if (pfn_swap_entry_to_page(entry) != pages[i]) + return false; + } else + return false; + } + + return true; +} +EXPORT_SYMBOL_GPL(check_device_exclusive_range); + void __put_anon_vma(struct anon_vma *anon_vma) { struct anon_vma *root = anon_vma->root; From patchwork Thu Mar 4 06:16:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alistair Popple X-Patchwork-Id: 12115533 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 171F9C433E6 for ; Thu, 4 Mar 2021 06:17:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9ECFC64EF6 for ; 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Thu, 4 Mar 2021 06:17:13 +0000 (UTC) X-FDA: 77881184346.08.19968FE Received: from hqnvemgate26.nvidia.com (hqnvemgate26.nvidia.com [216.228.121.65]) by imf07.hostedemail.com (Postfix) with ESMTP id CB5C2A0009DA for ; Thu, 4 Mar 2021 06:17:12 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate26.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 03 Mar 2021 22:17:12 -0800 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL111.nvidia.com (172.20.187.18) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:11 +0000 Received: from localhost (172.20.145.6) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:10 +0000 From: Alistair Popple To: , , , CC: , , , , , , , "Alistair Popple" , Jason Gunthorpe Subject: [PATCH v4 6/8] mm: Selftests for exclusive device memory Date: Thu, 4 Mar 2021 17:16:43 +1100 Message-ID: <20210304061645.29747-7-apopple@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210304061645.29747-1-apopple@nvidia.com> References: <20210304061645.29747-1-apopple@nvidia.com> MIME-Version: 1.0 X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To DRHQMAIL107.nvidia.com (10.27.9.16) DKIM-Signature: v=1; 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Signed-off-by: Alistair Popple Acked-by: Jason Gunthorpe Tested-by: Ralph Campbell Reviewed-by: Ralph Campbell --- lib/test_hmm.c | 124 ++++++++++++++ lib/test_hmm_uapi.h | 2 + tools/testing/selftests/vm/hmm-tests.c | 219 +++++++++++++++++++++++++ 3 files changed, 345 insertions(+) diff --git a/lib/test_hmm.c b/lib/test_hmm.c index 80a78877bd93..7dc3bc286934 100644 --- a/lib/test_hmm.c +++ b/lib/test_hmm.c @@ -25,6 +25,7 @@ #include #include #include +#include #include "test_hmm_uapi.h" @@ -46,6 +47,7 @@ struct dmirror_bounce { unsigned long cpages; }; +#define DPT_XA_TAG_ATOMIC 1UL #define DPT_XA_TAG_WRITE 3UL /* @@ -619,6 +621,54 @@ static void dmirror_migrate_alloc_and_copy(struct migrate_vma *args, } } +static int dmirror_check_atomic(struct dmirror *dmirror, unsigned long start, + unsigned long end) +{ + unsigned long pfn; + + for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) { + void *entry; + struct page *page; + + entry = xa_load(&dmirror->pt, pfn); + page = xa_untag_pointer(entry); + if (xa_pointer_tag(entry) == DPT_XA_TAG_ATOMIC) + return -EPERM; + } + + return 0; +} + +static int dmirror_atomic_map(unsigned long start, unsigned long end, + struct page **pages, struct dmirror *dmirror) +{ + unsigned long pfn, mapped = 0; + int i; + + /* Map the migrated pages into the device's page tables. */ + mutex_lock(&dmirror->mutex); + + for (i = 0, pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++, i++) { + void *entry; + + if (!pages[i]) + continue; + + entry = pages[i]; + entry = xa_tag_pointer(entry, DPT_XA_TAG_ATOMIC); + entry = xa_store(&dmirror->pt, pfn, entry, GFP_ATOMIC); + if (xa_is_err(entry)) { + mutex_unlock(&dmirror->mutex); + return xa_err(entry); + } + + mapped++; + } + + mutex_unlock(&dmirror->mutex); + return mapped; +} + static int dmirror_migrate_finalize_and_map(struct migrate_vma *args, struct dmirror *dmirror) { @@ -661,6 +711,71 @@ static int dmirror_migrate_finalize_and_map(struct migrate_vma *args, return 0; } +static int dmirror_exclusive(struct dmirror *dmirror, + struct hmm_dmirror_cmd *cmd) +{ + unsigned long start, end, addr; + unsigned long size = cmd->npages << PAGE_SHIFT; + struct mm_struct *mm = dmirror->notifier.mm; + struct page *pages[64]; + struct dmirror_bounce bounce; + unsigned long next; + int ret; + + start = cmd->addr; + end = start + size; + if (end < start) + return -EINVAL; + + /* Since the mm is for the mirrored process, get a reference first. */ + if (!mmget_not_zero(mm)) + return -EINVAL; + + mmap_read_lock(mm); + for (addr = start; addr < end; addr = next) { + int i, mapped; + + if (end < addr + (ARRAY_SIZE(pages) << PAGE_SHIFT)) + next = end; + else + next = addr + (ARRAY_SIZE(pages) << PAGE_SHIFT); + + ret = make_device_exclusive_range(mm, addr, next, pages); + mapped = dmirror_atomic_map(addr, next, pages, dmirror); + for (i = 0; i < ret; i++) { + if (pages[i]) { + unlock_page(pages[i]); + put_page(pages[i]); + } + } + + if (addr + (mapped << PAGE_SHIFT) < next) { + mmap_read_unlock(mm); + mmput(mm); + return -EBUSY; + } + } + mmap_read_unlock(mm); + mmput(mm); + + /* Return the migrated data for verification. */ + ret = dmirror_bounce_init(&bounce, start, size); + if (ret) + return ret; + mutex_lock(&dmirror->mutex); + ret = dmirror_do_read(dmirror, start, end, &bounce); + mutex_unlock(&dmirror->mutex); + if (ret == 0) { + if (copy_to_user(u64_to_user_ptr(cmd->ptr), bounce.ptr, + bounce.size)) + ret = -EFAULT; + } + + cmd->cpages = bounce.cpages; + dmirror_bounce_fini(&bounce); + return ret; +} + static int dmirror_migrate(struct dmirror *dmirror, struct hmm_dmirror_cmd *cmd) { @@ -949,6 +1064,15 @@ static long dmirror_fops_unlocked_ioctl(struct file *filp, ret = dmirror_migrate(dmirror, &cmd); break; + case HMM_DMIRROR_EXCLUSIVE: + ret = dmirror_exclusive(dmirror, &cmd); + break; + + case HMM_DMIRROR_CHECK_EXCLUSIVE: + ret = dmirror_check_atomic(dmirror, cmd.addr, + cmd.addr + (cmd.npages << PAGE_SHIFT)); + break; + case HMM_DMIRROR_SNAPSHOT: ret = dmirror_snapshot(dmirror, &cmd); break; diff --git a/lib/test_hmm_uapi.h b/lib/test_hmm_uapi.h index 670b4ef2a5b6..f14dea5dcd06 100644 --- a/lib/test_hmm_uapi.h +++ b/lib/test_hmm_uapi.h @@ -33,6 +33,8 @@ struct hmm_dmirror_cmd { #define HMM_DMIRROR_WRITE _IOWR('H', 0x01, struct hmm_dmirror_cmd) #define HMM_DMIRROR_MIGRATE _IOWR('H', 0x02, struct hmm_dmirror_cmd) #define HMM_DMIRROR_SNAPSHOT _IOWR('H', 0x03, struct hmm_dmirror_cmd) +#define HMM_DMIRROR_EXCLUSIVE _IOWR('H', 0x04, struct hmm_dmirror_cmd) +#define HMM_DMIRROR_CHECK_EXCLUSIVE _IOWR('H', 0x05, struct hmm_dmirror_cmd) /* * Values returned in hmm_dmirror_cmd.ptr for HMM_DMIRROR_SNAPSHOT. diff --git a/tools/testing/selftests/vm/hmm-tests.c b/tools/testing/selftests/vm/hmm-tests.c index 5d1ac691b9f4..5d3c5db9ed3a 100644 --- a/tools/testing/selftests/vm/hmm-tests.c +++ b/tools/testing/selftests/vm/hmm-tests.c @@ -1485,4 +1485,223 @@ TEST_F(hmm2, double_map) hmm_buffer_free(buffer); } +/* + * Basic check of exclusive faulting. + */ +TEST_F(hmm, exclusive) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size; + unsigned long i; + int *ptr; + int ret; + + npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift; + ASSERT_NE(npages, 0); + size = npages << self->page_shift; + + buffer = malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd = -1; + buffer->size = size; + buffer->mirror = malloc(size); + ASSERT_NE(buffer->mirror, NULL); + + buffer->ptr = mmap(NULL, size, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + /* Initialize buffer in system memory. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ptr[i] = i; + + /* Map memory exclusively for device access. */ + ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_EXCLUSIVE, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + /* Check what the device read. */ + for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + + /* Fault pages back to system memory and check them. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i]++, i); + + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i+1); + + /* Check atomic access revoked */ + ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_CHECK_EXCLUSIVE, buffer, npages); + ASSERT_EQ(ret, 0); + + hmm_buffer_free(buffer); +} + +TEST_F(hmm, exclusive_shared) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size; + int *ptr; + int ret, i; + + npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift; + ASSERT_NE(npages, 0); + size = npages << self->page_shift; + + buffer = malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd = -1; + buffer->size = size; + buffer->mirror = malloc(size); + ASSERT_NE(buffer->mirror, NULL); + + buffer->ptr = mmap(NULL, size, + PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + /* Initialize buffer in system memory. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ptr[i] = i; + + /* Map memory exclusively for device access. */ + ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_EXCLUSIVE, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + /* Check what the device read. */ + for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + + /* Fault pages back to system memory and check them. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i]++, i); + + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i+1); + + /* Check atomic access revoked */ + ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_CHECK_EXCLUSIVE, buffer, npages); + ASSERT_FALSE(ret); + + /* Map memory exclusively for device access again to check process tear down */ + ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_EXCLUSIVE, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + hmm_buffer_free(buffer); +} + +/* + * Same as above but for shared anonymous memory. + */ +TEST_F(hmm, exclusive_mprotect) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size; + unsigned long i; + int *ptr; + int ret; + + npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift; + ASSERT_NE(npages, 0); + size = npages << self->page_shift; + + buffer = malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd = -1; + buffer->size = size; + buffer->mirror = malloc(size); + ASSERT_NE(buffer->mirror, NULL); + + buffer->ptr = mmap(NULL, size, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + /* Initialize buffer in system memory. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ptr[i] = i; + + /* Map memory exclusively for device access. */ + ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_EXCLUSIVE, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + /* Check what the device read. */ + for (i = 0, ptr = buffer->mirror; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i); + + ret = mprotect(buffer->ptr, size, PROT_READ); + ASSERT_EQ(ret, 0); + + /* Simulate a device writing system memory. */ + ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_WRITE, buffer, npages); + ASSERT_EQ(ret, -EPERM); + + hmm_buffer_free(buffer); +} + +/* + * Check copy-on-write works. + */ +TEST_F(hmm, exclusive_cow) +{ + struct hmm_buffer *buffer; + unsigned long npages; + unsigned long size; + unsigned long i; + int *ptr; + int ret; + + npages = ALIGN(HMM_BUFFER_SIZE, self->page_size) >> self->page_shift; + ASSERT_NE(npages, 0); + size = npages << self->page_shift; + + buffer = malloc(sizeof(*buffer)); + ASSERT_NE(buffer, NULL); + + buffer->fd = -1; + buffer->size = size; + buffer->mirror = malloc(size); + ASSERT_NE(buffer->mirror, NULL); + + buffer->ptr = mmap(NULL, size, + PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, + buffer->fd, 0); + ASSERT_NE(buffer->ptr, MAP_FAILED); + + /* Initialize buffer in system memory. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ptr[i] = i; + + /* Map memory exclusively for device access. */ + ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_EXCLUSIVE, buffer, npages); + ASSERT_EQ(ret, 0); + ASSERT_EQ(buffer->cpages, npages); + + fork(); + + /* Fault pages back to system memory and check them. */ + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i]++, i); + + for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i) + ASSERT_EQ(ptr[i], i+1); + + hmm_buffer_free(buffer); +} + TEST_HARNESS_MAIN From patchwork Thu Mar 4 06:16:44 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alistair Popple X-Patchwork-Id: 12115535 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87913C43381 for ; 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Thu, 4 Mar 2021 06:17:16 +0000 (UTC) X-FDA: 77881184472.17.B0253BC Received: from hqnvemgate24.nvidia.com (hqnvemgate24.nvidia.com [216.228.121.143]) by imf25.hostedemail.com (Postfix) with ESMTP id A643E6000103 for ; Thu, 4 Mar 2021 06:17:14 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 03 Mar 2021 22:17:14 -0800 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL109.nvidia.com (172.20.187.15) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:13 +0000 Received: from localhost (172.20.145.6) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:13 +0000 From: Alistair Popple To: , , , CC: , , , , , , , "Alistair Popple" Subject: [PATCH v4 7/8] nouveau/svm: Refactor nouveau_range_fault Date: Thu, 4 Mar 2021 17:16:44 +1100 Message-ID: <20210304061645.29747-8-apopple@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210304061645.29747-1-apopple@nvidia.com> References: <20210304061645.29747-1-apopple@nvidia.com> MIME-Version: 1.0 X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To DRHQMAIL107.nvidia.com (10.27.9.16) DKIM-Signature: v=1; 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This doesn't introduce any functional change but makes it easier for a subsequent patch to alter the behaviour of nouveau_range_fault() to support GPU atomic operations. Signed-off-by: Alistair Popple --- drivers/gpu/drm/nouveau/nouveau_svm.c | 34 ++++++++++++++++----------- 1 file changed, 20 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c index f18bd53da052..cd7b47c946cf 100644 --- a/drivers/gpu/drm/nouveau/nouveau_svm.c +++ b/drivers/gpu/drm/nouveau/nouveau_svm.c @@ -567,18 +567,27 @@ static int nouveau_range_fault(struct nouveau_svmm *svmm, unsigned long hmm_pfns[1]; struct hmm_range range = { .notifier = ¬ifier->notifier, - .start = notifier->notifier.interval_tree.start, - .end = notifier->notifier.interval_tree.last + 1, .default_flags = hmm_flags, .hmm_pfns = hmm_pfns, .dev_private_owner = drm->dev, }; - struct mm_struct *mm = notifier->notifier.mm; + struct mm_struct *mm = svmm->notifier.mm; int ret; + ret = mmu_interval_notifier_insert(¬ifier->notifier, mm, + args->p.addr, args->p.size, + &nouveau_svm_mni_ops); + if (ret) + return ret; + + range.start = notifier->notifier.interval_tree.start; + range.end = notifier->notifier.interval_tree.last + 1; + while (true) { - if (time_after(jiffies, timeout)) - return -EBUSY; + if (time_after(jiffies, timeout)) { + ret = -EBUSY; + goto out; + } range.notifier_seq = mmu_interval_read_begin(range.notifier); mmap_read_lock(mm); @@ -587,7 +596,7 @@ static int nouveau_range_fault(struct nouveau_svmm *svmm, if (ret) { if (ret == -EBUSY) continue; - return ret; + goto out; } mutex_lock(&svmm->mutex); @@ -606,6 +615,9 @@ static int nouveau_range_fault(struct nouveau_svmm *svmm, svmm->vmm->vmm.object.client->super = false; mutex_unlock(&svmm->mutex); +out: + mmu_interval_notifier_remove(¬ifier->notifier); + return ret; } @@ -727,14 +739,8 @@ nouveau_svm_fault(struct nvif_notify *notify) } notifier.svmm = svmm; - ret = mmu_interval_notifier_insert(¬ifier.notifier, mm, - args.i.p.addr, args.i.p.size, - &nouveau_svm_mni_ops); - if (!ret) { - ret = nouveau_range_fault(svmm, svm->drm, &args.i, - sizeof(args), hmm_flags, ¬ifier); - mmu_interval_notifier_remove(¬ifier.notifier); - } + ret = nouveau_range_fault(svmm, svm->drm, &args.i, + sizeof(args), hmm_flags, ¬ifier); mmput(mm); limit = args.i.p.addr + args.i.p.size; From patchwork Thu Mar 4 06:16:45 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alistair Popple X-Patchwork-Id: 12115537 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9184BC433DB for ; Thu, 4 Mar 2021 06:17:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 36F2264EFD for ; 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Thu, 4 Mar 2021 06:17:19 +0000 (UTC) X-FDA: 77881184598.02.32DD7F7 Received: from hqnvemgate25.nvidia.com (hqnvemgate25.nvidia.com [216.228.121.64]) by imf25.hostedemail.com (Postfix) with ESMTP id 90CBA6000103 for ; Thu, 4 Mar 2021 06:17:17 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Wed, 03 Mar 2021 22:17:17 -0800 Received: from DRHQMAIL107.nvidia.com (10.27.9.16) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:17 +0000 Received: from localhost (172.20.145.6) by DRHQMAIL107.nvidia.com (10.27.9.16) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 4 Mar 2021 06:17:16 +0000 From: Alistair Popple To: , , , CC: , , , , , , , "Alistair Popple" Subject: [PATCH v4 8/8] nouveau/svm: Implement atomic SVM access Date: Thu, 4 Mar 2021 17:16:45 +1100 Message-ID: <20210304061645.29747-9-apopple@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210304061645.29747-1-apopple@nvidia.com> References: <20210304061645.29747-1-apopple@nvidia.com> MIME-Version: 1.0 X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To DRHQMAIL107.nvidia.com (10.27.9.16) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1614838637; bh=qO4yC80uoEqn5XcAiLxVhRuuZamrwUlLIEsRNkFlf1Q=; h=From:To:CC:Subject:Date:Message-ID:X-Mailer:In-Reply-To: References:MIME-Version:Content-Transfer-Encoding:Content-Type: X-Originating-IP:X-ClientProxiedBy; b=GsQLvPfRvQRfmqf8mKuT920WEkX5vWtgMSh+eV/98GjyrC6JKLo2eo6Yt+DLanQtF IswaFaECLMY1ZolVCUdDD8DV1pf+e/MpArqMrNIVm5DD+FJAXlLYk5h2lgvK2jkZvm F5V3ndKC+Fxo4wdES41b0yxarlcn3yXtR64Dc+91eE5tODMlABwAcbTPE1T7xduP60 xZ7OmmDg4X7xwfmh5BFITiCh9iUzg1n5dazObwwoJQXJFMTFG8UTKm97W29zUcxUsh ClcLGfneipAKeHx8lFzI+rb5wJ7h4VZaxETbcJh6ovoy3Au1arwgUwvfZMsQS4eAKh z8x1fii0ZDRvw== X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 90CBA6000103 X-Stat-Signature: qogkkm3me5iu5ziu5jdeoy5j1zczyyy1 Received-SPF: none (nvidia.com>: No applicable sender policy available) receiver=imf25; identity=mailfrom; envelope-from=""; helo=hqnvemgate25.nvidia.com; client-ip=216.228.121.64 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614838637-233985 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Some NVIDIA GPUs do not support direct atomic access to system memory via PCIe. Instead this must be emulated by granting the GPU exclusive access to the memory. This is achieved by replacing CPU page table entries with special swap entries that fault on userspace access. The driver then grants the GPU permission to update the page undergoing atomic access via the GPU page tables. When CPU access to the page is required a CPU fault is raised which calls into the device driver via MMU notifiers to revoke the atomic access. The original page table entries are then restored allowing CPU access to proceed. Signed-off-by: Alistair Popple --- v4: * Check that page table entries haven't changed before mapping on the device --- drivers/gpu/drm/nouveau/include/nvif/if000c.h | 1 + drivers/gpu/drm/nouveau/nouveau_svm.c | 107 ++++++++++++++++-- drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h | 1 + .../drm/nouveau/nvkm/subdev/mmu/vmmgp100.c | 6 + 4 files changed, 107 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/nouveau/include/nvif/if000c.h b/drivers/gpu/drm/nouveau/include/nvif/if000c.h index d6dd40f21eed..9c7ff56831c5 100644 --- a/drivers/gpu/drm/nouveau/include/nvif/if000c.h +++ b/drivers/gpu/drm/nouveau/include/nvif/if000c.h @@ -77,6 +77,7 @@ struct nvif_vmm_pfnmap_v0 { #define NVIF_VMM_PFNMAP_V0_APER 0x00000000000000f0ULL #define NVIF_VMM_PFNMAP_V0_HOST 0x0000000000000000ULL #define NVIF_VMM_PFNMAP_V0_VRAM 0x0000000000000010ULL +#define NVIF_VMM_PFNMAP_V0_A 0x0000000000000004ULL #define NVIF_VMM_PFNMAP_V0_W 0x0000000000000002ULL #define NVIF_VMM_PFNMAP_V0_V 0x0000000000000001ULL #define NVIF_VMM_PFNMAP_V0_NONE 0x0000000000000000ULL diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c index cd7b47c946cf..6d24424770e4 100644 --- a/drivers/gpu/drm/nouveau/nouveau_svm.c +++ b/drivers/gpu/drm/nouveau/nouveau_svm.c @@ -35,6 +35,7 @@ #include #include #include +#include struct nouveau_svm { struct nouveau_drm *drm; @@ -421,9 +422,9 @@ nouveau_svm_fault_cmp(const void *a, const void *b) return ret; if ((ret = (s64)fa->addr - fb->addr)) return ret; - /*XXX: atomic? */ - return (fa->access == 0 || fa->access == 3) - - (fb->access == 0 || fb->access == 3); + /* Atomic access (2) has highest priority */ + return (-1*(fa->access == 2) + (fa->access == 0 || fa->access == 3)) - + (-1*(fb->access == 2) + (fb->access == 0 || fb->access == 3)); } static void @@ -555,6 +556,84 @@ static void nouveau_hmm_convert_pfn(struct nouveau_drm *drm, args->p.phys[0] |= NVIF_VMM_PFNMAP_V0_W; } +static int nouveau_atomic_range_fault(struct nouveau_svmm *svmm, + struct nouveau_drm *drm, + struct nouveau_pfnmap_args *args, u32 size, + struct svm_notifier *notifier) +{ + unsigned long timeout = + jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT); + struct mm_struct *mm = svmm->notifier.mm; + struct page *page; + unsigned long start = args->p.addr; + unsigned long notifier_seq; + int ret = 0; + + ret = mmu_interval_notifier_insert(¬ifier->notifier, mm, + args->p.addr, args->p.size, + &nouveau_svm_mni_ops); + if (ret) + return ret; + + mmap_read_lock(mm); + make_device_exclusive_range(mm, start, start + PAGE_SIZE, &page); + mmap_read_unlock(mm); + if (!page) { + ret = -EINVAL; + goto out; + } + + while (true) { + if (time_after(jiffies, timeout)) { + ret = -EBUSY; + goto out; + } + + notifier_seq = mmu_interval_read_begin(¬ifier->notifier); + if (!check_device_exclusive_range(mm, start, start + PAGE_SIZE, + &page)) { + mmap_read_lock(mm); + make_device_exclusive_range(mm, start, + start + PAGE_SIZE, &page); + mmap_read_unlock(mm); + if (!page) { + ret = -EINVAL; + goto out; + } + continue; + } + mutex_lock(&svmm->mutex); + if (mmu_interval_read_retry(¬ifier->notifier, + notifier_seq)) { + mutex_unlock(&svmm->mutex); + continue; + } + break; + } + + /* Map the page on the GPU. */ + args->p.page = 12; + args->p.size = PAGE_SIZE; + args->p.addr = start; + args->p.phys[0] = page_to_phys(page) | + NVIF_VMM_PFNMAP_V0_V | + NVIF_VMM_PFNMAP_V0_W | + NVIF_VMM_PFNMAP_V0_A | + NVIF_VMM_PFNMAP_V0_HOST; + + svmm->vmm->vmm.object.client->super = true; + ret = nvif_object_ioctl(&svmm->vmm->vmm.object, args, size, NULL); + svmm->vmm->vmm.object.client->super = false; + mutex_unlock(&svmm->mutex); + + unlock_page(page); + put_page(page); + +out: + mmu_interval_notifier_remove(¬ifier->notifier); + return ret; +} + static int nouveau_range_fault(struct nouveau_svmm *svmm, struct nouveau_drm *drm, struct nouveau_pfnmap_args *args, u32 size, @@ -637,7 +716,7 @@ nouveau_svm_fault(struct nvif_notify *notify) unsigned long hmm_flags; u64 inst, start, limit; int fi, fn; - int replay = 0, ret; + int replay = 0, atomic = 0, ret; /* Parse available fault buffer entries into a cache, and update * the GET pointer so HW can reuse the entries. @@ -718,12 +797,14 @@ nouveau_svm_fault(struct nvif_notify *notify) /* * Determine required permissions based on GPU fault * access flags. - * XXX: atomic? */ switch (buffer->fault[fi]->access) { case 0: /* READ. */ hmm_flags = HMM_PFN_REQ_FAULT; break; + case 2: /* ATOMIC. */ + atomic = true; + break; case 3: /* PREFETCH. */ hmm_flags = 0; break; @@ -739,8 +820,14 @@ nouveau_svm_fault(struct nvif_notify *notify) } notifier.svmm = svmm; - ret = nouveau_range_fault(svmm, svm->drm, &args.i, - sizeof(args), hmm_flags, ¬ifier); + if (atomic) + ret = nouveau_atomic_range_fault(svmm, svm->drm, + &args.i, sizeof(args), + ¬ifier); + else + ret = nouveau_range_fault(svmm, svm->drm, &args.i, + sizeof(args), hmm_flags, + ¬ifier); mmput(mm); limit = args.i.p.addr + args.i.p.size; @@ -760,7 +847,11 @@ nouveau_svm_fault(struct nvif_notify *notify) !(args.phys[0] & NVIF_VMM_PFNMAP_V0_V)) || (buffer->fault[fi]->access != 0 /* READ. */ && buffer->fault[fi]->access != 3 /* PREFETCH. */ && - !(args.phys[0] & NVIF_VMM_PFNMAP_V0_W))) + !(args.phys[0] & NVIF_VMM_PFNMAP_V0_W)) || + (buffer->fault[fi]->access != 0 /* READ. */ && + buffer->fault[fi]->access != 1 /* WRITE. */ && + buffer->fault[fi]->access != 3 /* PREFETCH. */ && + !(args.phys[0] & NVIF_VMM_PFNMAP_V0_A))) break; } diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h index a2b179568970..f6188aa9171c 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.h @@ -178,6 +178,7 @@ void nvkm_vmm_unmap_region(struct nvkm_vmm *, struct nvkm_vma *); #define NVKM_VMM_PFN_APER 0x00000000000000f0ULL #define NVKM_VMM_PFN_HOST 0x0000000000000000ULL #define NVKM_VMM_PFN_VRAM 0x0000000000000010ULL +#define NVKM_VMM_PFN_A 0x0000000000000004ULL #define NVKM_VMM_PFN_W 0x0000000000000002ULL #define NVKM_VMM_PFN_V 0x0000000000000001ULL #define NVKM_VMM_PFN_NONE 0x0000000000000000ULL diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmmgp100.c b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmmgp100.c index 236db5570771..f02abd9cb4dd 100644 --- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmmgp100.c +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmmgp100.c @@ -88,6 +88,9 @@ gp100_vmm_pgt_pfn(struct nvkm_vmm *vmm, struct nvkm_mmu_pt *pt, if (!(*map->pfn & NVKM_VMM_PFN_W)) data |= BIT_ULL(6); /* RO. */ + if (!(*map->pfn & NVKM_VMM_PFN_A)) + data |= BIT_ULL(7); /* Atomic disable. */ + if (!(*map->pfn & NVKM_VMM_PFN_VRAM)) { addr = *map->pfn >> NVKM_VMM_PFN_ADDR_SHIFT; addr = dma_map_page(dev, pfn_to_page(addr), 0, @@ -322,6 +325,9 @@ gp100_vmm_pd0_pfn(struct nvkm_vmm *vmm, struct nvkm_mmu_pt *pt, if (!(*map->pfn & NVKM_VMM_PFN_W)) data |= BIT_ULL(6); /* RO. */ + if (!(*map->pfn & NVKM_VMM_PFN_A)) + data |= BIT_ULL(7); /* Atomic disable. */ + if (!(*map->pfn & NVKM_VMM_PFN_VRAM)) { addr = *map->pfn >> NVKM_VMM_PFN_ADDR_SHIFT; addr = dma_map_page(dev, pfn_to_page(addr), 0,