From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C76C9391 for ; Fri, 14 Jun 2024 04:47:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718340452; cv=none; b=kNhrR4r+TYMo+OxZwy/zeisKib0BvJBzXYOc4/XV52KSTJT+sth4eRTRWWCNTOYWKx60ppUJ4/3OCqHvwg06AN4G0qYQmUw+l5uabp/kczKVNXZLmSl01E8NUC4pKjVadqq3ORc8Tz3yV9gYIPVMWTflLBdRWGDZNTvd+fxynZQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718340452; c=relaxed/simple; bh=a8cvigCHrELnhA70e3V8GYVSIV/WOov/9PGDEAjq1vg=; h=Date:To:From:Subject:Message-Id; b=XrbyDErtIdH2v+H+22iEEr0W1h4bdGlshfSFgDFg93WnaXFtpK+p+/rxxXDieV+CsAN1KW3qdGPN2M/Tkwkys8WpP2nzzQ3DByDMWHRMEb9XKVdz95AgzRZLFjyI6exVHt9sPqclRQ3vKbrpHm3/Pij+7WrZuTfd9HLXlrfKpNI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=KG/bjrWE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="KG/bjrWE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5133EC2BD10; Fri, 14 Jun 2024 04:47:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1718340452; bh=a8cvigCHrELnhA70e3V8GYVSIV/WOov/9PGDEAjq1vg=; h=Date:To:From:Subject:From; b=KG/bjrWE83og1BI3Box70Lf2L426t1JPzje1ZfT5iUfkEPIJHWzafJwfYLLikDwve CqJkGJUNrL8VrOTDFv8tFlCCoQ8kNXYkl8szxFylTgpc9xm1G16uAbmbj9YGgtWLmV 13X8arcueIEmixTWEe7GXzA8J5vJq9Q0o27bVev4= Date: Thu, 13 Jun 2024 21:47:31 -0700 To: mm-commits@vger.kernel.org,zokeefe@google.com,ziy@nvidia.com,xiehuan09@gmail.com,willy@infradead.org,wangkefeng.wang@huawei.com,songmuchun@bytedance.com,sj@kernel.org,shy828301@gmail.com,ryan.roberts@arm.com,peterx@redhat.com,minchan@kernel.org,mhocko@suse.com,maskray@google.com,libang.li@antgroup.com,fengwei.yin@intel.com,david@redhat.com,baolin.wang@linux.alibaba.com,baohua@kernel.org,ioworker0@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-rmap-integrate-pmd-mapped-folio-splitting-into-pagewalk-loop.patch added to mm-unstable branch Message-Id: <20240614044732.5133EC2BD10@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/rmap: integrate PMD-mapped folio splitting into pagewalk loop has been added to the -mm mm-unstable branch. Its filename is mm-rmap-integrate-pmd-mapped-folio-splitting-into-pagewalk-loop.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-rmap-integrate-pmd-mapped-folio-splitting-into-pagewalk-loop.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Lance Yang Subject: mm/rmap: integrate PMD-mapped folio splitting into pagewalk loop Date: Fri, 14 Jun 2024 09:51:37 +0800 In preparation for supporting try_to_unmap_one() to unmap PMD-mapped folios, start the pagewalk first, then call split_huge_pmd_address() to split the folio. Link: https://lkml.kernel.org/r/20240614015138.31461-3-ioworker0@gmail.com Signed-off-by: Lance Yang Suggested-by: David Hildenbrand Suggested-by: Baolin Wang Cc: Bang Li Cc: Barry Song Cc: Fangrui Song Cc: Jeff Xie Cc: Kefeng Wang Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Minchan Kim Cc: Muchun Song Cc: Peter Xu Cc: Ryan Roberts Cc: SeongJae Park Cc: Yang Shi Cc: Yin Fengwei Cc: Zach O'Keefe Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/huge_mm.h | 6 +++++ include/linux/rmap.h | 24 +++++++++++++++++++++ mm/huge_memory.c | 42 +++++++++++++++++++------------------- mm/rmap.c | 21 +++++++++++++------ 4 files changed, 67 insertions(+), 26 deletions(-) --- a/include/linux/huge_mm.h~mm-rmap-integrate-pmd-mapped-folio-splitting-into-pagewalk-loop +++ a/include/linux/huge_mm.h @@ -428,6 +428,9 @@ static inline bool thp_migration_support return IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION); } +void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmd, bool freeze, struct folio *folio); + #else /* CONFIG_TRANSPARENT_HUGEPAGE */ static inline bool folio_test_pmd_mappable(struct folio *folio) @@ -490,6 +493,9 @@ static inline void __split_huge_pmd(stru unsigned long address, bool freeze, struct folio *folio) {} static inline void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, bool freeze, struct folio *folio) {} +static inline void split_huge_pmd_locked(struct vm_area_struct *vma, + unsigned long address, pmd_t *pmd, + bool freeze, struct folio *folio) {} #define split_huge_pud(__vma, __pmd, __address) \ do { } while (0) --- a/include/linux/rmap.h~mm-rmap-integrate-pmd-mapped-folio-splitting-into-pagewalk-loop +++ a/include/linux/rmap.h @@ -703,6 +703,30 @@ static inline void page_vma_mapped_walk_ spin_unlock(pvmw->ptl); } +/** + * page_vma_mapped_walk_restart - Restart the page table walk. + * @pvmw: Pointer to struct page_vma_mapped_walk. + * + * It restarts the page table walk when changes occur in the page + * table, such as splitting a PMD. Ensures that the PTL held during + * the previous walk is released and resets the state to allow for + * a new walk starting at the current address stored in pvmw->address. + */ +static inline void +page_vma_mapped_walk_restart(struct page_vma_mapped_walk *pvmw) +{ + WARN_ON_ONCE(!pvmw->pmd && !pvmw->pte); + + if (likely(pvmw->ptl)) + spin_unlock(pvmw->ptl); + else + WARN_ON_ONCE(1); + + pvmw->ptl = NULL; + pvmw->pmd = NULL; + pvmw->pte = NULL; +} + bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw); /* --- a/mm/huge_memory.c~mm-rmap-integrate-pmd-mapped-folio-splitting-into-pagewalk-loop +++ a/mm/huge_memory.c @@ -2582,6 +2582,27 @@ static void __split_huge_pmd_locked(stru pmd_populate(mm, pmd, pgtable); } +void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address, + pmd_t *pmd, bool freeze, struct folio *folio) +{ + VM_WARN_ON_ONCE(folio && !folio_test_pmd_mappable(folio)); + VM_WARN_ON_ONCE(!IS_ALIGNED(address, HPAGE_PMD_SIZE)); + VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); + VM_BUG_ON(freeze && !folio); + + /* + * When the caller requests to set up a migration entry, we + * require a folio to check the PMD against. Otherwise, there + * is a risk of replacing the wrong folio. + */ + if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || + is_pmd_migration_entry(*pmd)) { + if (folio && folio != pmd_folio(*pmd)) + return; + __split_huge_pmd_locked(vma, pmd, address, freeze); + } +} + void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long address, bool freeze, struct folio *folio) { @@ -2593,26 +2614,7 @@ void __split_huge_pmd(struct vm_area_str (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE); mmu_notifier_invalidate_range_start(&range); ptl = pmd_lock(vma->vm_mm, pmd); - - /* - * If caller asks to setup a migration entry, we need a folio to check - * pmd against. Otherwise we can end up replacing wrong folio. - */ - VM_BUG_ON(freeze && !folio); - VM_WARN_ON_ONCE(folio && !folio_test_locked(folio)); - - if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) || - is_pmd_migration_entry(*pmd)) { - /* - * It's safe to call pmd_page when folio is set because it's - * guaranteed that pmd is present. - */ - if (folio && folio != pmd_folio(*pmd)) - goto out; - __split_huge_pmd_locked(vma, pmd, range.start, freeze); - } - -out: + split_huge_pmd_locked(vma, range.start, pmd, freeze, folio); spin_unlock(ptl); mmu_notifier_invalidate_range_end(&range); } --- a/mm/rmap.c~mm-rmap-integrate-pmd-mapped-folio-splitting-into-pagewalk-loop +++ a/mm/rmap.c @@ -1642,9 +1642,6 @@ static bool try_to_unmap_one(struct foli if (flags & TTU_SYNC) pvmw.flags = PVMW_SYNC; - if (flags & TTU_SPLIT_HUGE_PMD) - split_huge_pmd_address(vma, address, false, folio); - /* * 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 @@ -1670,9 +1667,6 @@ static bool try_to_unmap_one(struct foli mmu_notifier_invalidate_range_start(&range); while (page_vma_mapped_walk(&pvmw)) { - /* Unexpected PMD-mapped THP? */ - VM_BUG_ON_FOLIO(!pvmw.pte, folio); - /* * If the folio is in an mlock()d vma, we must not swap it out. */ @@ -1684,6 +1678,21 @@ static bool try_to_unmap_one(struct foli goto walk_abort; } + if (!pvmw.pte && (flags & TTU_SPLIT_HUGE_PMD)) { + /* + * We temporarily have to drop the PTL and start once + * again from that now-PTE-mapped page table. + */ + split_huge_pmd_locked(vma, pvmw.address, pvmw.pmd, + false, folio); + flags &= ~TTU_SPLIT_HUGE_PMD; + page_vma_mapped_walk_restart(&pvmw); + continue; + } + + /* Unexpected PMD-mapped THP? */ + VM_BUG_ON_FOLIO(!pvmw.pte, folio); + pfn = pte_pfn(ptep_get(pvmw.pte)); subpage = folio_page(folio, pfn - folio_pfn(folio)); address = pvmw.address; _ Patches currently in -mm which might be from ioworker0@gmail.com are mm-rmap-remove-duplicated-exit-code-in-pagewalk-loop.patch mm-rmap-integrate-pmd-mapped-folio-splitting-into-pagewalk-loop.patch mm-vmscan-avoid-split-lazyfree-thp-during-shrink_folio_list.patch mm-mlock-implement-folio_mlock_step-using-folio_pte_batch.patch