From patchwork Fri Jun 19 21:56:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ralph Campbell X-Patchwork-Id: 11615209 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9F22E1731 for ; Fri, 19 Jun 2020 21:58:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 79B002222C for ; Fri, 19 Jun 2020 21:58:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="PhIU7f5O" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728509AbgFSV6A (ORCPT ); Fri, 19 Jun 2020 17:58:00 -0400 Received: from hqnvemgate24.nvidia.com ([216.228.121.143]:8525 "EHLO hqnvemgate24.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728306AbgFSV5L (ORCPT ); Fri, 19 Jun 2020 17:57:11 -0400 Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate24.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 19 Jun 2020 14:55:26 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Fri, 19 Jun 2020 14:57:07 -0700 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Fri, 19 Jun 2020 14:57:07 -0700 Received: from HQMAIL107.nvidia.com (172.20.187.13) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 19 Jun 2020 21:57:00 +0000 Received: from hqnvemgw03.nvidia.com (10.124.88.68) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Fri, 19 Jun 2020 21:57:00 +0000 Received: from rcampbell-dev.nvidia.com (Not Verified[10.110.48.66]) by hqnvemgw03.nvidia.com with Trustwave SEG (v7,5,8,10121) id ; Fri, 19 Jun 2020 14:56:59 -0700 From: Ralph Campbell To: , , , , CC: Jerome Glisse , John Hubbard , Christoph Hellwig , Jason Gunthorpe , "Ben Skeggs" , Andrew Morton , Shuah Khan , Ralph Campbell Subject: [PATCH 13/16] mm: support THP migration to device private memory Date: Fri, 19 Jun 2020 14:56:46 -0700 Message-ID: <20200619215649.32297-14-rcampbell@nvidia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200619215649.32297-1-rcampbell@nvidia.com> References: <20200619215649.32297-1-rcampbell@nvidia.com> MIME-Version: 1.0 X-NVConfidentiality: public DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1592603726; bh=NiU+p+cqny9cDxqnaY4eal9DB3rHGdwVblI9dTjdDco=; h=X-PGP-Universal:From:To:CC:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:X-NVConfidentiality: Content-Transfer-Encoding:Content-Type; b=PhIU7f5O7h7IxVCzmBW32R154zTfAOQMURde2VyYSnchOC/NKCpKxa2o70LcM80Vp lah140H6x4mHYkqL5nlUmQ41LQ6F0CpaaQaz7WbcvYdbE3tPgyWoY+avUCQKcwZbw2 kwadiGdGvM3DGRJulPm/e63Hu5UCN+nNwCuZ7yMqRkKXxSJ/fdSrNxoCCdUI/CHegT VkZuNUCedDfllZ0Etfc7oFM2xuFgAtH3jqmr/TFfY4hbJJSP1InOmtEkek9WgKaHtZ GnfRn8xm9g8Pni5Uo+kY7/O4+HroF0QcK8RgNTH3CICljFM1QQfNiS00/qpoRtsCKK i8XJVsKBf/a1A== Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Support transparent huge page migration to ZONE_DEVICE private memory. A new flag (MIGRATE_PFN_COMPOUND) is added to the input PFN array to indicate the huge page was fully mapped by the CPU. Export prep_compound_page() so that device drivers can create huge device private pages after calling memremap_pages(). Signed-off-by: Ralph Campbell --- include/linux/migrate.h | 1 + include/linux/mm.h | 1 + mm/huge_memory.c | 30 ++++-- mm/internal.h | 1 - mm/memory.c | 10 +- mm/memremap.c | 9 +- mm/migrate.c | 226 ++++++++++++++++++++++++++++++++-------- mm/page_alloc.c | 1 + 8 files changed, 226 insertions(+), 53 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 3e546cbf03dd..f6a64965c8bd 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -166,6 +166,7 @@ static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm, #define MIGRATE_PFN_MIGRATE (1UL << 1) #define MIGRATE_PFN_LOCKED (1UL << 2) #define MIGRATE_PFN_WRITE (1UL << 3) +#define MIGRATE_PFN_COMPOUND (1UL << 4) #define MIGRATE_PFN_SHIFT 6 static inline struct page *migrate_pfn_to_page(unsigned long mpfn) diff --git a/include/linux/mm.h b/include/linux/mm.h index dc7b87310c10..020b9dd3cddb 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -932,6 +932,7 @@ static inline unsigned int page_shift(struct page *page) } void free_compound_page(struct page *page); +void prep_compound_page(struct page *page, unsigned int order); #ifdef CONFIG_MMU /* diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 78c84bee7e29..25d95f7b1e98 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1663,23 +1663,35 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, } else { struct page *page = NULL; int flush_needed = 1; + bool is_anon = false; if (pmd_present(orig_pmd)) { page = pmd_page(orig_pmd); + is_anon = PageAnon(page); page_remove_rmap(page, true); VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); VM_BUG_ON_PAGE(!PageHead(page), page); } else if (thp_migration_supported()) { swp_entry_t entry; - VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); entry = pmd_to_swp_entry(orig_pmd); - page = pfn_to_page(swp_offset(entry)); + if (is_device_private_entry(entry)) { + page = device_private_entry_to_page(entry); + is_anon = PageAnon(page); + page_remove_rmap(page, true); + VM_BUG_ON_PAGE(page_mapcount(page) < 0, page); + VM_BUG_ON_PAGE(!PageHead(page), page); + put_page(page); + } else { + VM_BUG_ON(!is_pmd_migration_entry(orig_pmd)); + page = pfn_to_page(swp_offset(entry)); + is_anon = PageAnon(page); + } flush_needed = 0; } else WARN_ONCE(1, "Non present huge pmd without pmd migration enabled!"); - if (PageAnon(page)) { + if (is_anon) { zap_deposited_table(tlb->mm, pmd); add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); } else { @@ -1778,8 +1790,8 @@ bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr, /* * Returns * - 0 if PMD could not be locked - * - 1 if PMD was locked but protections unchange and TLB flush unnecessary - * - HPAGE_PMD_NR is protections changed and TLB flush necessary + * - 1 if PMD was locked but protections unchanged and TLB flush unnecessary + * - HPAGE_PMD_NR if protections changed and TLB flush necessary */ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, pgprot_t newprot, unsigned long cp_flags) @@ -2689,7 +2701,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { if (!list_empty(page_deferred_list(head))) { ds_queue->split_queue_len--; - list_del(page_deferred_list(head)); + list_del_init(page_deferred_list(head)); } spin_unlock(&ds_queue->split_queue_lock); if (mapping) { @@ -2743,7 +2755,7 @@ void free_transhuge_page(struct page *page) spin_lock_irqsave(&ds_queue->split_queue_lock, flags); if (!list_empty(page_deferred_list(page))) { ds_queue->split_queue_len--; - list_del(page_deferred_list(page)); + list_del_init(page_deferred_list(page)); } spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); free_compound_page(page); @@ -2963,6 +2975,10 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) pmde = pmd_mksoft_dirty(pmde); if (is_write_migration_entry(entry)) pmde = maybe_pmd_mkwrite(pmde, vma); + if (unlikely(is_device_private_page(new))) { + entry = make_device_private_entry(new, pmd_write(pmde)); + pmde = swp_entry_to_pmd(entry); + } flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE); if (PageAnon(new)) diff --git a/mm/internal.h b/mm/internal.h index 9886db20d94f..58f051a14dae 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -196,7 +196,6 @@ extern void __putback_isolated_page(struct page *page, unsigned int order, extern void memblock_free_pages(struct page *page, unsigned long pfn, unsigned int order); extern void __free_pages_core(struct page *page, unsigned int order); -extern void prep_compound_page(struct page *page, unsigned int order); extern void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags); extern int user_min_free_kbytes; diff --git a/mm/memory.c b/mm/memory.c index dc7f3543b1fd..4e03d1a2ead5 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4322,9 +4322,15 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, barrier(); if (unlikely(is_swap_pmd(orig_pmd))) { + swp_entry_t entry = pmd_to_swp_entry(orig_pmd); + + if (is_device_private_entry(entry)) { + vmf.page = device_private_entry_to_page(entry); + return vmf.page->pgmap->ops->migrate_to_ram(&vmf); + } VM_BUG_ON(thp_migration_supported() && - !is_pmd_migration_entry(orig_pmd)); - if (is_pmd_migration_entry(orig_pmd)) + !is_migration_entry(entry)); + if (is_migration_entry(entry)) pmd_migration_entry_wait(mm, vmf.pmd); return 0; } diff --git a/mm/memremap.c b/mm/memremap.c index 03e38b7a38f1..4231054188b4 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -132,8 +132,13 @@ void memunmap_pages(struct dev_pagemap *pgmap) int nid; dev_pagemap_kill(pgmap); - for_each_device_pfn(pfn, pgmap) - put_page(pfn_to_page(pfn)); + for_each_device_pfn(pfn, pgmap) { + struct page *page = pfn_to_page(pfn); + unsigned int order = compound_order(page); + + put_page(page); + pfn += (1U << order) - 1; + } dev_pagemap_cleanup(pgmap); /* make sure to access a memmap that was actually initialized */ diff --git a/mm/migrate.c b/mm/migrate.c index 87c52e0ee580..1536677cefc9 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -51,6 +51,7 @@ #include #include +#include #define CREATE_TRACE_POINTS #include @@ -2185,6 +2186,8 @@ static int migrate_vma_collect_hole(unsigned long start, for (addr = start; addr < end; addr += PAGE_SIZE) { migrate->src[migrate->npages] = flags; + if ((addr & ~PMD_MASK) == 0 && (end & ~PMD_MASK) == 0) + migrate->src[migrate->npages] |= MIGRATE_PFN_COMPOUND; migrate->dst[migrate->npages] = 0; migrate->npages++; migrate->cpages++; @@ -2219,48 +2222,87 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, unsigned long addr = start, unmapped = 0; spinlock_t *ptl; pte_t *ptep; + pmd_t pmd; again: - if (pmd_none(*pmdp)) + pmd = READ_ONCE(*pmdp); + if (pmd_none(pmd)) return migrate_vma_collect_hole(start, end, -1, walk); - if (pmd_trans_huge(*pmdp)) { + if (pmd_trans_huge(pmd) || !pmd_present(pmd)) { struct page *page; + unsigned long write = 0; + int ret; ptl = pmd_lock(mm, pmdp); - if (unlikely(!pmd_trans_huge(*pmdp))) { - spin_unlock(ptl); - goto again; - } + if (pmd_trans_huge(*pmdp)) { + page = pmd_page(*pmdp); + if (is_huge_zero_page(page)) { + spin_unlock(ptl); + return migrate_vma_collect_hole(start, end, -1, + walk); + } + if (pmd_write(*pmdp)) + write = MIGRATE_PFN_WRITE; + } else if (!pmd_present(*pmdp)) { + swp_entry_t entry = pmd_to_swp_entry(*pmdp); - page = pmd_page(*pmdp); - if (is_huge_zero_page(page)) { - spin_unlock(ptl); - split_huge_pmd(vma, pmdp, addr); - if (pmd_trans_unstable(pmdp)) + if (!is_device_private_entry(entry)) { + spin_unlock(ptl); return migrate_vma_collect_skip(start, end, walk); + } + page = device_private_entry_to_page(entry); + if (is_write_device_private_entry(entry)) + write = MIGRATE_PFN_WRITE; } else { - int ret; + spin_unlock(ptl); + goto again; + } - get_page(page); + get_page(page); + if (unlikely(!trylock_page(page))) { spin_unlock(ptl); - if (unlikely(!trylock_page(page))) - return migrate_vma_collect_skip(start, end, - walk); - ret = split_huge_page(page); - unlock_page(page); put_page(page); - if (ret) - return migrate_vma_collect_skip(start, end, - walk); - if (pmd_none(*pmdp)) - return migrate_vma_collect_hole(start, end, -1, - walk); + return migrate_vma_collect_skip(start, end, walk); + } +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION + if ((start & HPAGE_PMD_MASK) == start && + start + HPAGE_PMD_SIZE == end) { + struct page_vma_mapped_walk vmw = { + .vma = vma, + .address = start, + .pmd = pmdp, + .ptl = ptl, + }; + + migrate->src[migrate->npages] = write | + migrate_pfn(page_to_pfn(page)) | + MIGRATE_PFN_MIGRATE | MIGRATE_PFN_LOCKED | + MIGRATE_PFN_COMPOUND; + migrate->dst[migrate->npages] = 0; + migrate->npages++; + migrate->cpages++; + migrate_vma_collect_skip(start + PAGE_SIZE, end, walk); + + /* Note that this also removes the page from the rmap. */ + set_pmd_migration_entry(&vmw, page); + spin_unlock(ptl); + + return 0; } +#endif + spin_unlock(ptl); + ret = split_huge_page(page); + unlock_page(page); + put_page(page); + if (ret) + return migrate_vma_collect_skip(start, end, walk); + if (pmd_none(*pmdp)) + return migrate_vma_collect_hole(start, end, -1, walk); } - if (unlikely(pmd_bad(*pmdp))) + if (unlikely(pmd_bad(pmd) || pmd_devmap(pmd))) return migrate_vma_collect_skip(start, end, walk); ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl); @@ -2310,8 +2352,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp, mpfn |= pte_write(pte) ? MIGRATE_PFN_WRITE : 0; } - /* FIXME support THP */ - if (!page || !page->mapping || PageTransCompound(page)) { + if (!page || !page->mapping) { mpfn = 0; goto next; } @@ -2420,14 +2461,6 @@ static bool migrate_vma_check_page(struct page *page) */ int extra = 1; - /* - * FIXME support THP (transparent huge page), it is bit more complex to - * check them than regular pages, because they can be mapped with a pmd - * or with a pte (split pte mapping). - */ - if (PageCompound(page)) - return false; - /* Page from ZONE_DEVICE have one extra reference */ if (is_zone_device_page(page)) { /* @@ -2726,13 +2759,115 @@ int migrate_vma_setup(struct migrate_vma *args) } EXPORT_SYMBOL(migrate_vma_setup); +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION +/* + * This code closely follows: + * do_huge_pmd_anonymous_page() + * __do_huge_pmd_anonymous_page() + * except that the page being inserted is likely to be a device private page + * instead of an allocated or zero page. + */ +static int insert_huge_pmd_anonymous_page(struct vm_area_struct *vma, + unsigned long haddr, + struct page *page, + unsigned long *src, + unsigned long *dst, + pmd_t *pmdp) +{ + struct mm_struct *mm = vma->vm_mm; + unsigned int i; + spinlock_t *ptl; + bool flush = false; + pgtable_t pgtable; + gfp_t gfp; + pmd_t entry; + + if (WARN_ON_ONCE(compound_order(page) != HPAGE_PMD_ORDER)) + goto abort; + + if (unlikely(anon_vma_prepare(vma))) + goto abort; + + prep_transhuge_page(page); + + gfp = GFP_TRANSHUGE_LIGHT; + if (mem_cgroup_charge(page, mm, gfp)) + goto abort; + + pgtable = pte_alloc_one(mm); + if (unlikely(!pgtable)) + goto abort; + + __SetPageUptodate(page); + + if (is_zone_device_page(page)) { + if (!is_device_private_page(page)) + goto pgtable_abort; + entry = swp_entry_to_pmd(make_device_private_entry(page, + vma->vm_flags & VM_WRITE)); + } else { + entry = mk_huge_pmd(page, vma->vm_page_prot); + entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); + } + + ptl = pmd_lock(mm, pmdp); + + if (check_stable_address_space(mm)) + goto unlock_abort; + + /* + * Check for userfaultfd but do not deliver the fault. Instead, + * just back off. + */ + if (userfaultfd_missing(vma)) + goto unlock_abort; + + if (pmd_present(*pmdp)) { + if (!is_huge_zero_pmd(*pmdp)) + goto unlock_abort; + flush = true; + } else if (!pmd_none(*pmdp)) + goto unlock_abort; + + get_page(page); + page_add_new_anon_rmap(page, vma, haddr, true); + if (!is_device_private_page(page)) + lru_cache_add_active_or_unevictable(page, vma); + if (flush) { + pte_free(mm, pgtable); + flush_cache_range(vma, haddr, haddr + HPAGE_PMD_SIZE); + pmdp_invalidate(vma, haddr, pmdp); + } else { + pgtable_trans_huge_deposit(mm, pmdp, pgtable); + mm_inc_nr_ptes(mm); + } + set_pmd_at(mm, haddr, pmdp, entry); + update_mmu_cache_pmd(vma, haddr, pmdp); + add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); + spin_unlock(ptl); + count_vm_event(THP_FAULT_ALLOC); + count_memcg_event_mm(mm, THP_FAULT_ALLOC); + + return 0; + +unlock_abort: + spin_unlock(ptl); +pgtable_abort: + pte_free(mm, pgtable); +abort: + for (i = 0; i < HPAGE_PMD_NR; i++) + src[i] &= ~MIGRATE_PFN_MIGRATE; + return -EINVAL; +} +#endif + /* * This code closely matches the code in: * __handle_mm_fault() * handle_pte_fault() * do_anonymous_page() - * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE - * private page. + * to map in an anonymous zero page except the struct page is already allocated + * and will likely be a ZONE_DEVICE private page. */ static void migrate_vma_insert_page(struct migrate_vma *migrate, unsigned long addr, @@ -2766,7 +2901,16 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, if (!pmdp) goto abort; - if (pmd_trans_huge(*pmdp) || pmd_devmap(*pmdp)) +#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION + if (*dst & MIGRATE_PFN_COMPOUND) { + int ret = insert_huge_pmd_anonymous_page(vma, addr, page, src, + dst, pmdp); + if (ret) + goto abort; + return; + } +#endif + if (pmd_trans_huge(*pmdp) || pmd_devmap(*pmdp) || pmd_bad(*pmdp)) goto abort; /* @@ -2804,7 +2948,8 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, swp_entry = make_device_private_entry(page, vma->vm_flags & VM_WRITE); entry = swp_entry_to_pte(swp_entry); - } + } else + goto abort; } else { entry = mk_pte(page, vma->vm_page_prot); if (vma->vm_flags & VM_WRITE) @@ -2833,10 +2978,10 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, goto unlock_abort; inc_mm_counter(mm, MM_ANONPAGES); + get_page(page); page_add_new_anon_rmap(page, vma, addr, false); if (!is_zone_device_page(page)) lru_cache_add_active_or_unevictable(page, vma); - get_page(page); if (flush) { flush_cache_page(vma, addr, pte_pfn(*ptep)); @@ -2850,7 +2995,6 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate, } pte_unmap_unlock(ptep, ptl); - *src = MIGRATE_PFN_MIGRATE; return; unlock_abort: diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 48eb0f1410d4..a852ed2f204c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -686,6 +686,7 @@ void prep_compound_page(struct page *page, unsigned int order) if (hpage_pincount_available(page)) atomic_set(compound_pincount_ptr(page), 0); } +EXPORT_SYMBOL_GPL(prep_compound_page); #ifdef CONFIG_DEBUG_PAGEALLOC unsigned int _debug_guardpage_minorder;