From patchwork Wed Sep 11 06:56:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dev Jain X-Patchwork-Id: 13799774 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B9F36EE0211 for ; Wed, 11 Sep 2024 06:59:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jRyjgCZOWySZsDxKY8ZNoyWbYW5aApirUx8H/d7Vh9Y=; b=4pcEJ6q0YbFdRr/Blmg0prv3Zq j4TqnaRTg2+E+CxKg1OP0T9+8P2U5NRKTr+QlzVISOG0JzyL/gZrIzXTdUgJNLrCva+DOHGmx7PY9 HCkDi1nz+wOEYMpsB5uUmdJhZLr50KPEDboYEw56MAsGExbzv2sP/gdIPkSXa7zH943MJzMcRFQdq fAgWUhQavt3WGl29uAMTnxhAMHJjaQ7uH5uM2mlttzTdV1BpMa6c0xujirRj0/QBiAJDpqy/MALzT Pz8x3OO+RmucKMgPC2Q03mpH3hwlrzlhgtuOeyKdPZ1kmHKUUx1E9lmTLyWGuTGMs+T5W8AqJylyR DEJQXtKQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1soHKD-00000008Lht-3NUO; Wed, 11 Sep 2024 06:59:37 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1soHHM-00000008L2f-1Td6 for linux-arm-kernel@lists.infradead.org; Wed, 11 Sep 2024 06:56:41 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0FC911007; Tue, 10 Sep 2024 23:57:09 -0700 (PDT) Received: from e116581.blr.arm.com (e116581.arm.com [10.162.40.31]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E1A943F64C; Tue, 10 Sep 2024 23:56:30 -0700 (PDT) From: Dev Jain To: akpm@linux-foundation.org, david@redhat.com, willy@infradead.org, kirill.shutemov@linux.intel.com Cc: ryan.roberts@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, cl@gentwo.org, vbabka@suse.cz, mhocko@suse.com, apopple@nvidia.com, dave.hansen@linux.intel.com, will@kernel.org, baohua@kernel.org, jack@suse.cz, mark.rutland@arm.com, hughd@google.com, aneesh.kumar@kernel.org, yang@os.amperecomputing.com, peterx@redhat.com, ioworker0@gmail.com, jglisse@google.com, wangkefeng.wang@huawei.com, ziy@nvidia.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dev Jain Subject: [PATCH v3 2/2] mm: Allocate THP on hugezeropage wp-fault Date: Wed, 11 Sep 2024 12:26:00 +0530 Message-Id: <20240911065600.1002644-3-dev.jain@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240911065600.1002644-1-dev.jain@arm.com> References: <20240911065600.1002644-1-dev.jain@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240910_235640_527662_05777464 X-CRM114-Status: GOOD ( 14.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Introduce do_huge_zero_wp_pmd() to handle wp-fault on a hugezeropage and replace it with a PMD-mapped THP. Change the helper introduced in the previous patch to flush TLB entry corresponding to the hugezeropage. In case of failure, fallback to splitting the PMD. Signed-off-by: Dev Jain --- mm/huge_memory.c | 52 +++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 49 insertions(+), 3 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index b96a1ff2bf40..3e28946a805f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -987,16 +987,20 @@ static void __pmd_thp_fault_success_stats(struct vm_area_struct *vma) static void map_pmd_thp(struct folio *folio, struct vm_fault *vmf, struct vm_area_struct *vma, unsigned long haddr) { - pmd_t entry; + pmd_t entry, old_pmd; + bool is_pmd_none = pmd_none(*vmf->pmd); entry = mk_huge_pmd(&folio->page, vma->vm_page_prot); entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); folio_add_new_anon_rmap(folio, vma, haddr, RMAP_EXCLUSIVE); folio_add_lru_vma(folio, vma); + if (!is_pmd_none) + old_pmd = pmdp_huge_clear_flush(vma, haddr, vmf->pmd); set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry); update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR); - mm_inc_nr_ptes(vma->vm_mm); + if (is_pmd_none) + mm_inc_nr_ptes(vma->vm_mm); } static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf) @@ -1576,6 +1580,41 @@ void huge_pmd_set_accessed(struct vm_fault *vmf) spin_unlock(vmf->ptl); } +static vm_fault_t do_huge_zero_wp_pmd(struct vm_fault *vmf, unsigned long haddr) +{ + struct vm_area_struct *vma = vmf->vma; + gfp_t gfp = vma_thp_gfp_mask(vma); + struct mmu_notifier_range range; + struct folio *folio; + vm_fault_t ret = 0; + + folio = pmd_thp_fault_alloc(gfp, vma, haddr, vmf->address); + if (unlikely(!folio)) { + ret = VM_FAULT_FALLBACK; + goto out; + } + + mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, haddr, + haddr + HPAGE_PMD_SIZE); + mmu_notifier_invalidate_range_start(&range); + vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); + if (unlikely(!pmd_same(pmdp_get(vmf->pmd), vmf->orig_pmd))) + goto release; + ret = check_stable_address_space(vma->vm_mm); + if (ret) + goto release; + map_pmd_thp(folio, vmf, vma, haddr); + __pmd_thp_fault_success_stats(vma); + goto unlock; +release: + folio_put(folio); +unlock: + spin_unlock(vmf->ptl); + mmu_notifier_invalidate_range_end(&range); +out: + return ret; +} + vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) { const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE; @@ -1588,8 +1627,15 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd); VM_BUG_ON_VMA(!vma->anon_vma, vma); - if (is_huge_zero_pmd(orig_pmd)) + if (is_huge_zero_pmd(orig_pmd)) { + vm_fault_t ret = do_huge_zero_wp_pmd(vmf, haddr); + + if (!(ret & VM_FAULT_FALLBACK)) + return ret; + + /* Fallback to splitting PMD if THP cannot be allocated */ goto fallback; + } spin_lock(vmf->ptl);