June 2021 - Linux-stable-mirror

+ mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm: page_vma_mapped_walk(): settle PageHuge on entry has been added to the -mm tree. Its filename is mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-page_vma_mapped_walk-settle-pa… and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_vma_mapped_walk-settle-pa… 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm: page_vma_mapped_walk(): settle PageHuge on entry page_vma_mapped_walk() cleanup: get the hugetlbfs PageHuge case out of the way at the start, so no need to worry about it later. Link: https://lkml.kernel.org/r/e31a483c-6d73-a6bb-26c5-43c3b880a2@google.com Signed-off-by: Hugh Dickins <hughd(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Reviewed-by: Peter Xu <peterx(a)redhat.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: "Kirill A. Shutemov" <kirill.shutemov(a)linux.intel.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: Ralph Campbell <rcampbell(a)nvidia.com> Cc: Wang Yugui <wangyugui(a)e16-tech.com> Cc: Will Deacon <will(a)kernel.org> Cc: Yang Shi <shy828301(a)gmail.com> Cc: Zi Yan <ziy(a)nvidia.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/page_vma_mapped.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/mm/page_vma_mapped.c~mm-page_vma_mapped_walk-settle-pagehuge-on-entry +++ a/mm/page_vma_mapped.c @@ -153,10 +153,11 @@ bool page_vma_mapped_walk(struct page_vm if (pvmw->pmd && !pvmw->pte) return not_found(pvmw); - if (pvmw->pte) - goto next_pte; - if (unlikely(PageHuge(page))) { + /* The only possible mapping was handled on last iteration */ + if (pvmw->pte) + return not_found(pvmw); + /* when pud is not present, pte will be NULL */ pvmw->pte = huge_pte_offset(mm, pvmw->address, page_size(page)); if (!pvmw->pte) @@ -168,6 +169,9 @@ bool page_vma_mapped_walk(struct page_vm return not_found(pvmw); return true; } + + if (pvmw->pte) + goto next_pte; restart: pgd = pgd_offset(mm, pvmw->address); if (!pgd_present(*pgd)) @@ -233,7 +237,7 @@ restart: return true; next_pte: /* Seek to next pte only makes sense for THP */ - if (!PageTransHuge(page) || PageHuge(page)) + if (!PageTransHuge(page)) return not_found(pvmw); end = vma_address_end(page, pvmw->vma); do { _ Patches currently in -mm which might be from hughd(a)google.com are mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch mm-page_vma_mapped_walk-use-pmd_read_atomic.patch mm-page_vma_mapped_walk-use-pmde-for-pvmw-pmd.patch mm-page_vma_mapped_walk-prettify-pvmw_migration-block.patch mm-page_vma_mapped_walk-crossing-page-table-boundary.patch mm-page_vma_mapped_walk-add-a-level-of-indentation.patch mm-page_vma_mapped_walk-use-goto-instead-of-while-1.patch mm-page_vma_mapped_walk-get-vma_address_end-earlier.patch mm-thp-fix-page_vma_mapped_walk-if-thp-mapped-by-ptes.patch mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch mm-thp-remap_page-is-only-needed-on-anonymous-thp.patch mm-hwpoison_user_mappings-try_to_unmap-with-ttu_sync.patch

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+ mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm: page_vma_mapped_walk(): use page for pvmw->page has been added to the -mm tree. Its filename is mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-page_vma_mapped_walk-use-page-… and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_vma_mapped_walk-use-page-… 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm: page_vma_mapped_walk(): use page for pvmw->page Patch series "mm: page_vma_mapped_walk() cleanup and THP fixes". I've marked all of these for stable: many are merely cleanups, but I think they are much better before the main fix than after. This patch (of 11): page_vma_mapped_walk() cleanup: sometimes the local copy of pvwm->page was used, sometimes pvmw->page itself: use the local copy "page" throughout. Link: https://lkml.kernel.org/r/589b358c-febc-c88e-d4c2-7834b37fa7bf@google.com Link: https://lkml.kernel.org/r/88e67645-f467-c279-bf5e-af4b5c6b13eb@google.com Signed-off-by: Hugh Dickins <hughd(a)google.com> Reviewed-by: Alistair Popple <apopple(a)nvidia.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Reviewed-by: Peter Xu <peterx(a)redhat.com> Cc: Yang Shi <shy828301(a)gmail.com> Cc: Wang Yugui <wangyugui(a)e16-tech.com> Cc: Matthew Wilcox <willy(a)infradead.org> Cc: Ralph Campbell <rcampbell(a)nvidia.com> Cc: Zi Yan <ziy(a)nvidia.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/page_vma_mapped.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/mm/page_vma_mapped.c~mm-page_vma_mapped_walk-use-page-for-pvmw-page +++ a/mm/page_vma_mapped.c @@ -156,7 +156,7 @@ bool page_vma_mapped_walk(struct page_vm if (pvmw->pte) goto next_pte; - if (unlikely(PageHuge(pvmw->page))) { + if (unlikely(PageHuge(page))) { /* when pud is not present, pte will be NULL */ pvmw->pte = huge_pte_offset(mm, pvmw->address, page_size(page)); if (!pvmw->pte) @@ -217,8 +217,7 @@ restart: * cannot return prematurely, while zap_huge_pmd() has * cleared *pmd but not decremented compound_mapcount(). */ - if ((pvmw->flags & PVMW_SYNC) && - PageTransCompound(pvmw->page)) { + if ((pvmw->flags & PVMW_SYNC) && PageTransCompound(page)) { spinlock_t *ptl = pmd_lock(mm, pvmw->pmd); spin_unlock(ptl); @@ -234,9 +233,9 @@ restart: return true; next_pte: /* Seek to next pte only makes sense for THP */ - if (!PageTransHuge(pvmw->page) || PageHuge(pvmw->page)) + if (!PageTransHuge(page) || PageHuge(page)) return not_found(pvmw); - end = vma_address_end(pvmw->page, pvmw->vma); + end = vma_address_end(page, pvmw->vma); do { pvmw->address += PAGE_SIZE; if (pvmw->address >= end) _ Patches currently in -mm which might be from hughd(a)google.com are mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch mm-page_vma_mapped_walk-use-pmd_read_atomic.patch mm-page_vma_mapped_walk-use-pmde-for-pvmw-pmd.patch mm-page_vma_mapped_walk-prettify-pvmw_migration-block.patch mm-page_vma_mapped_walk-crossing-page-table-boundary.patch mm-page_vma_mapped_walk-add-a-level-of-indentation.patch mm-page_vma_mapped_walk-use-goto-instead-of-while-1.patch mm-page_vma_mapped_walk-get-vma_address_end-earlier.patch mm-thp-fix-page_vma_mapped_walk-if-thp-mapped-by-ptes.patch mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch mm-thp-remap_page-is-only-needed-on-anonymous-thp.patch mm-hwpoison_user_mappings-try_to_unmap-with-ttu_sync.patch

4 years

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+ mm-thp-replace-debug_vm-bug-with-vm_warn-when-unmap-fails-for-split.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split has been added to the -mm tree. Its filename is mm-thp-replace-debug_vm-bug-with-vm_warn-when-unmap-fails-for-split.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-thp-replace-debug_vm-bug-with-… and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-replace-debug_vm-bug-with-… 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Yang Shi <shy828301(a)gmail.com> Subject: mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split When debugging the bug reported by Wang Yugui [1], try_to_unmap() may fail, but the first VM_BUG_ON_PAGE() just checks page_mapcount() however it may miss the failure when head page is unmapped but other subpage is mapped. Then the second DEBUG_VM BUG() that check total mapcount would catch it. This may incur some confusion. And this is not a fatal issue, so consolidate the two DEBUG_VM checks into one VM_WARN_ON_ONCE_PAGE(). [1] https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/ Link: https://lkml.kernel.org/r/d0f0db68-98b8-ebfb-16dc-f29df24cf012@google.com Signed-off-by: Yang Shi <shy828301(a)gmail.com> Reviewed-by: Zi Yan <ziy(a)nvidia.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Signed-off-by: Hugh Dickins <hughd(a)google.com> Cc: <stable(a)vger.kernel.org> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Jan Kara <jack(a)suse.cz> Cc: Jue Wang <juew(a)google.com> Cc: "Matthew Wilcox (Oracle)" <willy(a)infradead.org> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi(a)nec.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Peter Xu <peterx(a)redhat.com> Cc: Ralph Campbell <rcampbell(a)nvidia.com> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Wang Yugui <wangyugui(a)e16-tech.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/huge_memory.c | 24 +++++++----------------- 1 file changed, 7 insertions(+), 17 deletions(-) --- a/mm/huge_memory.c~mm-thp-replace-debug_vm-bug-with-vm_warn-when-unmap-fails-for-split +++ a/mm/huge_memory.c @@ -2352,15 +2352,15 @@ static void unmap_page(struct page *page { enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_SYNC | 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); - VM_BUG_ON_PAGE(!unmap_success, page); + try_to_unmap(page, ttu_flags); + + VM_WARN_ON_ONCE_PAGE(page_mapped(page), page); } static void remap_page(struct page *page, unsigned int nr) @@ -2671,7 +2671,7 @@ int split_huge_page_to_list(struct page struct deferred_split *ds_queue = get_deferred_split_queue(head); struct anon_vma *anon_vma = NULL; struct address_space *mapping = NULL; - int count, mapcount, extra_pins, ret; + int extra_pins, ret; pgoff_t end; VM_BUG_ON_PAGE(is_huge_zero_page(head), head); @@ -2730,7 +2730,6 @@ int split_huge_page_to_list(struct page } unmap_page(head); - VM_BUG_ON_PAGE(compound_mapcount(head), head); /* block interrupt reentry in xa_lock and spinlock */ local_irq_disable(); @@ -2748,9 +2747,7 @@ int split_huge_page_to_list(struct page /* Prevent deferred_split_scan() touching ->_refcount */ spin_lock(&ds_queue->split_queue_lock); - count = page_count(head); - mapcount = total_mapcount(head); - if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) { + if (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)); @@ -2770,16 +2767,9 @@ int split_huge_page_to_list(struct page __split_huge_page(page, list, end); ret = 0; } else { - if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) { - pr_alert("total_mapcount: %u, page_count(): %u\n", - mapcount, count); - if (PageTail(page)) - dump_page(head, NULL); - dump_page(page, "total_mapcount(head) > 0"); - BUG(); - } spin_unlock(&ds_queue->split_queue_lock); -fail: if (mapping) +fail: + if (mapping) xa_unlock(&mapping->i_pages); local_irq_enable(); remap_page(head, thp_nr_pages(head)); _ Patches currently in -mm which might be from shy828301(a)gmail.com are mm-thp-replace-debug_vm-bug-with-vm_warn-when-unmap-fails-for-split.patch mm-mempolicy-dont-have-to-split-pmd-for-huge-zero-page.patch mm-memory-add-orig_pmd-to-struct-vm_fault.patch mm-memory-make-numa_migrate_prep-non-static.patch mm-thp-refactor-numa-fault-handling.patch mm-migrate-account-thp-numa-migration-counters-correctly.patch mm-migrate-dont-split-thp-for-misplaced-numa-page.patch mm-migrate-check-mapcount-for-thp-instead-of-refcount.patch mm-thp-skip-make-pmd-prot_none-if-thp-migration-is-not-supported.patch mm-rmap-make-try_to_unmap-void-function.patch

4 years

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+ mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/thp: unmap_mapping_page() to fix THP truncate_cleanup_page() has been added to the -mm tree. Its filename is mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-thp-unmap_mapping_page-to-fix-… and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-unmap_mapping_page-to-fix-… 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/thp: unmap_mapping_page() to fix THP truncate_cleanup_page() There is a race between THP unmapping and truncation, when truncate sees pmd_none() and skips the entry, after munmap's zap_huge_pmd() cleared it, but before its page_remove_rmap() gets to decrement compound_mapcount: generating false "BUG: Bad page cache" reports that the page is still mapped when deleted. This commit fixes that, but not in the way I hoped. The first attempt used try_to_unmap(page, TTU_SYNC|TTU_IGNORE_MLOCK) instead of unmap_mapping_range() in truncate_cleanup_page(): it has often been an annoyance that we usually call unmap_mapping_range() with no pages locked, but there apply it to a single locked page. try_to_unmap() looks more suitable for a single locked page. However, try_to_unmap_one() contains a VM_BUG_ON_PAGE(!pvmw.pte,page): it is used to insert THP migration entries, but not used to unmap THPs. Copy zap_huge_pmd() and add THP handling now? Perhaps, but their TLB needs are different, I'm too ignorant of the DAX cases, and couldn't decide how far to go for anon+swap. Set that aside. The second attempt took a different tack: make no change in truncate.c, but modify zap_huge_pmd() to insert an invalidated huge pmd instead of clearing it initially, then pmd_clear() between page_remove_rmap() and unlocking at the end. Nice. But powerpc blows that approach out of the water, with its serialize_against_pte_lookup(), and interesting pgtable usage. It would need serious help to get working on powerpc (with a minor optimization issue on s390 too). Set that aside. Just add an "if (page_mapped(page)) synchronize_rcu();" or other such delay, after unmapping in truncate_cleanup_page()? Perhaps, but though that's likely to reduce or eliminate the number of incidents, it would give less assurance of whether we had identified the problem correctly. This successful iteration introduces "unmap_mapping_page(page)" instead of try_to_unmap(), and goes the usual unmap_mapping_range_tree() route, with an addition to details. Then zap_pmd_range() watches for this case, and does spin_unlock(pmd_lock) if so - just like page_vma_mapped_walk() now does in the PVMW_SYNC case. Not pretty, but safe. Note that unmap_mapping_page() is doing a VM_BUG_ON(!PageLocked) to assert its interface; but currently that's only used to make sure that page->mapping is stable, and zap_pmd_range() doesn't care if the page is locked or not. Along these lines, in invalidate_inode_pages2_range() move the initial unmap_mapping_range() out from under page lock, before then calling unmap_mapping_page() under page lock if still mapped. Link: https://lkml.kernel.org/r/a2a4a148-cdd8-942c-4ef8-51b77f643dbe@google.com Fixes: fc127da085c2 ("truncate: handle file thp") Signed-off-by: Hugh Dickins <hughd(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Reviewed-by: Yang Shi <shy828301(a)gmail.com> Cc: <stable(a)vger.kernel.org> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Jan Kara <jack(a)suse.cz> Cc: Jue Wang <juew(a)google.com> Cc: "Matthew Wilcox (Oracle)" <willy(a)infradead.org> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi(a)nec.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Peter Xu <peterx(a)redhat.com> Cc: Ralph Campbell <rcampbell(a)nvidia.com> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Wang Yugui <wangyugui(a)e16-tech.com> Cc: Zi Yan <ziy(a)nvidia.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/mm.h | 3 +++ mm/memory.c | 41 +++++++++++++++++++++++++++++++++++++++++ mm/truncate.c | 43 +++++++++++++++++++------------------------ 3 files changed, 63 insertions(+), 24 deletions(-) --- a/include/linux/mm.h~mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page +++ a/include/linux/mm.h @@ -1719,6 +1719,7 @@ struct zap_details { struct address_space *check_mapping; /* Check page->mapping if set */ pgoff_t first_index; /* Lowest page->index to unmap */ pgoff_t last_index; /* Highest page->index to unmap */ + struct page *single_page; /* Locked page to be unmapped */ }; struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, @@ -1766,6 +1767,7 @@ extern vm_fault_t handle_mm_fault(struct extern int fixup_user_fault(struct mm_struct *mm, unsigned long address, unsigned int fault_flags, bool *unlocked); +void unmap_mapping_page(struct page *page); void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, pgoff_t nr, bool even_cows); void unmap_mapping_range(struct address_space *mapping, @@ -1786,6 +1788,7 @@ static inline int fixup_user_fault(struc BUG(); return -EFAULT; } +static inline void unmap_mapping_page(struct page *page) { } static inline void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, pgoff_t nr, bool even_cows) { } static inline void unmap_mapping_range(struct address_space *mapping, --- a/mm/memory.c~mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page +++ a/mm/memory.c @@ -1361,7 +1361,18 @@ static inline unsigned long zap_pmd_rang else if (zap_huge_pmd(tlb, vma, pmd, addr)) goto next; /* fall through */ + } else if (details && details->single_page && + PageTransCompound(details->single_page) && + next - addr == HPAGE_PMD_SIZE && pmd_none(*pmd)) { + spinlock_t *ptl = pmd_lock(tlb->mm, pmd); + /* + * Take and drop THP pmd lock so that we cannot return + * prematurely, while zap_huge_pmd() has cleared *pmd, + * but not yet decremented compound_mapcount(). + */ + spin_unlock(ptl); } + /* * Here there can be other concurrent MADV_DONTNEED or * trans huge page faults running, and if the pmd is @@ -3237,6 +3248,36 @@ static inline void unmap_mapping_range_t } /** + * unmap_mapping_page() - Unmap single page from processes. + * @page: The locked page to be unmapped. + * + * Unmap this page from any userspace process which still has it mmaped. + * Typically, for efficiency, the range of nearby pages has already been + * unmapped by unmap_mapping_pages() or unmap_mapping_range(). But once + * truncation or invalidation holds the lock on a page, it may find that + * the page has been remapped again: and then uses unmap_mapping_page() + * to unmap it finally. + */ +void unmap_mapping_page(struct page *page) +{ + struct address_space *mapping = page->mapping; + struct zap_details details = { }; + + VM_BUG_ON(!PageLocked(page)); + VM_BUG_ON(PageTail(page)); + + details.check_mapping = mapping; + details.first_index = page->index; + details.last_index = page->index + thp_nr_pages(page) - 1; + details.single_page = page; + + i_mmap_lock_write(mapping); + if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) + unmap_mapping_range_tree(&mapping->i_mmap, &details); + i_mmap_unlock_write(mapping); +} + +/** * unmap_mapping_pages() - Unmap pages from processes. * @mapping: The address space containing pages to be unmapped. * @start: Index of first page to be unmapped. --- a/mm/truncate.c~mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page +++ a/mm/truncate.c @@ -167,13 +167,10 @@ void do_invalidatepage(struct page *page * its lock, b) when a concurrent invalidate_mapping_pages got there first and * c) when tmpfs swizzles a page between a tmpfs inode and swapper_space. */ -static void -truncate_cleanup_page(struct address_space *mapping, struct page *page) +static void truncate_cleanup_page(struct page *page) { - if (page_mapped(page)) { - unsigned int nr = thp_nr_pages(page); - unmap_mapping_pages(mapping, page->index, nr, false); - } + if (page_mapped(page)) + unmap_mapping_page(page); if (page_has_private(page)) do_invalidatepage(page, 0, thp_size(page)); @@ -218,7 +215,7 @@ int truncate_inode_page(struct address_s if (page->mapping != mapping) return -EIO; - truncate_cleanup_page(mapping, page); + truncate_cleanup_page(page); delete_from_page_cache(page); return 0; } @@ -325,7 +322,7 @@ void truncate_inode_pages_range(struct a index = indices[pagevec_count(&pvec) - 1] + 1; truncate_exceptional_pvec_entries(mapping, &pvec, indices); for (i = 0; i < pagevec_count(&pvec); i++) - truncate_cleanup_page(mapping, pvec.pages[i]); + truncate_cleanup_page(pvec.pages[i]); delete_from_page_cache_batch(mapping, &pvec); for (i = 0; i < pagevec_count(&pvec); i++) unlock_page(pvec.pages[i]); @@ -639,6 +636,16 @@ int invalidate_inode_pages2_range(struct continue; } + if (!did_range_unmap && page_mapped(page)) { + /* + * If page is mapped, before taking its lock, + * zap the rest of the file in one hit. + */ + unmap_mapping_pages(mapping, index, + (1 + end - index), false); + did_range_unmap = 1; + } + lock_page(page); WARN_ON(page_to_index(page) != index); if (page->mapping != mapping) { @@ -646,23 +653,11 @@ int invalidate_inode_pages2_range(struct continue; } wait_on_page_writeback(page); - if (page_mapped(page)) { - if (!did_range_unmap) { - /* - * Zap the rest of the file in one hit. - */ - unmap_mapping_pages(mapping, index, - (1 + end - index), false); - did_range_unmap = 1; - } else { - /* - * Just zap this page - */ - unmap_mapping_pages(mapping, index, - 1, false); - } - } + + if (page_mapped(page)) + unmap_mapping_page(page); BUG_ON(page_mapped(page)); + ret2 = do_launder_page(mapping, page); if (ret2 == 0) { if (!invalidate_complete_page2(mapping, page)) _ Patches currently in -mm which might be from hughd(a)google.com are mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch mm-page_vma_mapped_walk-use-pmd_read_atomic.patch mm-page_vma_mapped_walk-use-pmde-for-pvmw-pmd.patch mm-page_vma_mapped_walk-prettify-pvmw_migration-block.patch mm-page_vma_mapped_walk-crossing-page-table-boundary.patch mm-page_vma_mapped_walk-add-a-level-of-indentation.patch mm-page_vma_mapped_walk-use-goto-instead-of-while-1.patch mm-page_vma_mapped_walk-get-vma_address_end-earlier.patch mm-thp-fix-page_vma_mapped_walk-if-thp-mapped-by-ptes.patch mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch mm-thp-remap_page-is-only-needed-on-anonymous-thp.patch mm-hwpoison_user_mappings-try_to_unmap-with-ttu_sync.patch

4 years

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+ mm-thp-fix-page_address_in_vma-on-file-thp-tails.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/thp: fix page_address_in_vma() on file THP tails has been added to the -mm tree. Its filename is mm-thp-fix-page_address_in_vma-on-file-thp-tails.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-thp-fix-page_address_in_vma-on… and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-fix-page_address_in_vma-on… 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Jue Wang <juew(a)google.com> Subject: mm/thp: fix page_address_in_vma() on file THP tails Anon THP tails were already supported, but memory-failure may need to use page_address_in_vma() on file THP tails, which its page->mapping check did not permit: fix it. hughd adds: no current usage is known to hit the issue, but this does fix a subtle trap in a general helper: best fixed in stable sooner than later. Link: https://lkml.kernel.org/r/a0d9b53-bf5d-8bab-ac5-759dc61819c1@google.com Fixes: 800d8c63b2e9 ("shmem: add huge pages support") Signed-off-by: Jue Wang <juew(a)google.com> Signed-off-by: Hugh Dickins <hughd(a)google.com> Reviewed-by: Matthew Wilcox (Oracle) <willy(a)infradead.org> Reviewed-by: Yang Shi <shy828301(a)gmail.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Cc: <stable(a)vger.kernel.org> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Jan Kara <jack(a)suse.cz> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi(a)nec.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Peter Xu <peterx(a)redhat.com> Cc: Ralph Campbell <rcampbell(a)nvidia.com> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Wang Yugui <wangyugui(a)e16-tech.com> Cc: Zi Yan <ziy(a)nvidia.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/rmap.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/mm/rmap.c~mm-thp-fix-page_address_in_vma-on-file-thp-tails +++ a/mm/rmap.c @@ -716,11 +716,11 @@ unsigned long page_address_in_vma(struct if (!vma->anon_vma || !page__anon_vma || vma->anon_vma->root != page__anon_vma->root) return -EFAULT; - } else if (page->mapping) { - if (!vma->vm_file || vma->vm_file->f_mapping != page->mapping) - return -EFAULT; - } else + } else if (!vma->vm_file) { + return -EFAULT; + } else if (vma->vm_file->f_mapping != compound_head(page)->mapping) { return -EFAULT; + } return vma_address(page, vma); } _ Patches currently in -mm which might be from juew(a)google.com are mm-thp-fix-page_address_in_vma-on-file-thp-tails.patch

4 years

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+ mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/thp: fix vma_address() if virtual address below file offset has been added to the -mm tree. Its filename is mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-thp-fix-vma_address-if-virtual… and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-fix-vma_address-if-virtual… 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/thp: fix vma_address() if virtual address below file offset Running certain tests with a DEBUG_VM kernel would crash within hours, on the total_mapcount BUG() in split_huge_page_to_list(), while trying to free up some memory by punching a hole in a shmem huge page: split's try_to_unmap() was unable to find all the mappings of the page (which, on a !DEBUG_VM kernel, would then keep the huge page pinned in memory). When that BUG() was changed to a WARN(), it would later crash on the VM_BUG_ON_VMA(end < vma->vm_start || start >= vma->vm_end, vma) in mm/internal.h:vma_address(), used by rmap_walk_file() for try_to_unmap(). vma_address() is usually correct, but there's a wraparound case when the vm_start address is unusually low, but vm_pgoff not so low: vma_address() chooses max(start, vma->vm_start), but that decides on the wrong address, because start has become almost ULONG_MAX. Rewrite vma_address() to be more careful about vm_pgoff; move the VM_BUG_ON_VMA() out of it, returning -EFAULT for errors, so that it can be safely used from page_mapped_in_vma() and page_address_in_vma() too. Add vma_address_end() to apply similar care to end address calculation, in page_vma_mapped_walk() and page_mkclean_one() and try_to_unmap_one(); though it raises a question of whether callers would do better to supply pvmw->end to page_vma_mapped_walk() - I chose not, for a smaller patch. An irritation is that their apparent generality breaks down on KSM pages, which cannot be located by the page->index that page_to_pgoff() uses: as 4b0ece6fa016 ("mm: migrate: fix remove_migration_pte() for ksm pages") once discovered. I dithered over the best thing to do about that, and have ended up with a VM_BUG_ON_PAGE(PageKsm) in both vma_address() and vma_address_end(); though the only place in danger of using it on them was try_to_unmap_one(). Sidenote: vma_address() and vma_address_end() now use compound_nr() on a head page, instead of thp_size(): to make the right calculation on a hugetlbfs page, whether or not THPs are configured. try_to_unmap() is used on hugetlbfs pages, but perhaps the wrong calculation never mattered. Link: https://lkml.kernel.org/r/caf1c1a3-7cfb-7f8f-1beb-ba816e932825@google.com Fixes: a8fa41ad2f6f ("mm, rmap: check all VMAs that PTE-mapped THP can be part of") Signed-off-by: Hugh Dickins <hughd(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Cc: <stable(a)vger.kernel.org> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Jan Kara <jack(a)suse.cz> Cc: Jue Wang <juew(a)google.com> Cc: "Matthew Wilcox (Oracle)" <willy(a)infradead.org> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi(a)nec.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Peter Xu <peterx(a)redhat.com> Cc: Ralph Campbell <rcampbell(a)nvidia.com> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Wang Yugui <wangyugui(a)e16-tech.com> Cc: Yang Shi <shy828301(a)gmail.com> Cc: Zi Yan <ziy(a)nvidia.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/internal.h | 51 ++++++++++++++++++++++++++++++----------- mm/page_vma_mapped.c | 16 ++++-------- mm/rmap.c | 16 ++++++------ 3 files changed, 52 insertions(+), 31 deletions(-) --- a/mm/internal.h~mm-thp-fix-vma_address-if-virtual-address-below-file-offset +++ a/mm/internal.h @@ -384,27 +384,52 @@ static inline void mlock_migrate_page(st extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma); /* - * At what user virtual address is page expected in @vma? + * At what user virtual address is page expected in vma? + * Returns -EFAULT if all of the page is outside the range of vma. + * If page is a compound head, the entire compound page is considered. */ static inline unsigned long -__vma_address(struct page *page, struct vm_area_struct *vma) +vma_address(struct page *page, struct vm_area_struct *vma) { - pgoff_t pgoff = page_to_pgoff(page); - return vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); + pgoff_t pgoff; + unsigned long address; + + VM_BUG_ON_PAGE(PageKsm(page), page); /* KSM page->index unusable */ + pgoff = page_to_pgoff(page); + if (pgoff >= vma->vm_pgoff) { + address = vma->vm_start + + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); + /* Check for address beyond vma (or wrapped through 0?) */ + if (address < vma->vm_start || address >= vma->vm_end) + address = -EFAULT; + } else if (PageHead(page) && + pgoff + compound_nr(page) - 1 >= vma->vm_pgoff) { + /* Test above avoids possibility of wrap to 0 on 32-bit */ + address = vma->vm_start; + } else { + address = -EFAULT; + } + return address; } +/* + * Then at what user virtual address will none of the page be found in vma? + * Assumes that vma_address() already returned a good starting address. + * If page is a compound head, the entire compound page is considered. + */ static inline unsigned long -vma_address(struct page *page, struct vm_area_struct *vma) +vma_address_end(struct page *page, struct vm_area_struct *vma) { - unsigned long start, end; - - start = __vma_address(page, vma); - end = start + thp_size(page) - PAGE_SIZE; - - /* page should be within @vma mapping range */ - VM_BUG_ON_VMA(end < vma->vm_start || start >= vma->vm_end, vma); + pgoff_t pgoff; + unsigned long address; - return max(start, vma->vm_start); + VM_BUG_ON_PAGE(PageKsm(page), page); /* KSM page->index unusable */ + pgoff = page_to_pgoff(page) + compound_nr(page); + address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); + /* Check for address beyond vma (or wrapped through 0?) */ + if (address < vma->vm_start || address > vma->vm_end) + address = vma->vm_end; + return address; } static inline struct file *maybe_unlock_mmap_for_io(struct vm_fault *vmf, --- a/mm/page_vma_mapped.c~mm-thp-fix-vma_address-if-virtual-address-below-file-offset +++ a/mm/page_vma_mapped.c @@ -228,18 +228,18 @@ restart: if (!map_pte(pvmw)) goto next_pte; while (1) { + unsigned long end; + if (check_pte(pvmw)) return true; next_pte: /* Seek to next pte only makes sense for THP */ if (!PageTransHuge(pvmw->page) || PageHuge(pvmw->page)) return not_found(pvmw); + end = vma_address_end(pvmw->page, pvmw->vma); do { pvmw->address += PAGE_SIZE; - if (pvmw->address >= pvmw->vma->vm_end || - pvmw->address >= - __vma_address(pvmw->page, pvmw->vma) + - thp_size(pvmw->page)) + if (pvmw->address >= end) return not_found(pvmw); /* Did we cross page table boundary? */ if (pvmw->address % PMD_SIZE == 0) { @@ -277,14 +277,10 @@ int page_mapped_in_vma(struct page *page .vma = vma, .flags = PVMW_SYNC, }; - unsigned long start, end; - - start = __vma_address(page, vma); - end = start + thp_size(page) - PAGE_SIZE; - if (unlikely(end < vma->vm_start || start >= vma->vm_end)) + pvmw.address = vma_address(page, vma); + if (pvmw.address == -EFAULT) return 0; - pvmw.address = max(start, vma->vm_start); if (!page_vma_mapped_walk(&pvmw)) return 0; page_vma_mapped_walk_done(&pvmw); --- a/mm/rmap.c~mm-thp-fix-vma_address-if-virtual-address-below-file-offset +++ a/mm/rmap.c @@ -707,7 +707,6 @@ static bool should_defer_flush(struct mm */ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma) { - unsigned long address; if (PageAnon(page)) { struct anon_vma *page__anon_vma = page_anon_vma(page); /* @@ -722,10 +721,8 @@ unsigned long page_address_in_vma(struct return -EFAULT; } else return -EFAULT; - address = __vma_address(page, vma); - if (unlikely(address < vma->vm_start || address >= vma->vm_end)) - return -EFAULT; - return address; + + return vma_address(page, vma); } pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address) @@ -919,7 +916,7 @@ static bool page_mkclean_one(struct page */ mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE, 0, vma, vma->vm_mm, address, - min(vma->vm_end, address + page_size(page))); + vma_address_end(page, vma)); mmu_notifier_invalidate_range_start(&range); while (page_vma_mapped_walk(&pvmw)) { @@ -1435,9 +1432,10 @@ static bool try_to_unmap_one(struct page * Note that the page can not be free in this function as call of * try_to_unmap() must hold a reference on the page. */ + range.end = PageKsm(page) ? + address + PAGE_SIZE : vma_address_end(page, vma); mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, - address, - min(vma->vm_end, address + page_size(page))); + address, range.end); if (PageHuge(page)) { /* * If sharing is possible, start and end will be adjusted @@ -1889,6 +1887,7 @@ static void rmap_walk_anon(struct page * struct vm_area_struct *vma = avc->vma; unsigned long address = vma_address(page, vma); + VM_BUG_ON_VMA(address == -EFAULT, vma); cond_resched(); if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg)) @@ -1943,6 +1942,7 @@ static void rmap_walk_file(struct page * pgoff_start, pgoff_end) { unsigned long address = vma_address(page, vma); + VM_BUG_ON_VMA(address == -EFAULT, vma); cond_resched(); if (rwc->invalid_vma && rwc->invalid_vma(vma, rwc->arg)) _ Patches currently in -mm which might be from hughd(a)google.com are mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch mm-page_vma_mapped_walk-use-pmd_read_atomic.patch mm-page_vma_mapped_walk-use-pmde-for-pvmw-pmd.patch mm-page_vma_mapped_walk-prettify-pvmw_migration-block.patch mm-page_vma_mapped_walk-crossing-page-table-boundary.patch mm-page_vma_mapped_walk-add-a-level-of-indentation.patch mm-page_vma_mapped_walk-use-goto-instead-of-while-1.patch mm-page_vma_mapped_walk-get-vma_address_end-earlier.patch mm-thp-fix-page_vma_mapped_walk-if-thp-mapped-by-ptes.patch mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch mm-thp-remap_page-is-only-needed-on-anonymous-thp.patch mm-hwpoison_user_mappings-try_to_unmap-with-ttu_sync.patch

4 years

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+ mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/thp: try_to_unmap() use TTU_SYNC for safe splitting has been added to the -mm tree. Its filename is mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-thp-try_to_unmap-use-ttu_sync-… and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-try_to_unmap-use-ttu_sync-… 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/thp: try_to_unmap() use TTU_SYNC for safe splitting Stressing huge tmpfs often crashed on unmap_page()'s VM_BUG_ON_PAGE (!unmap_success): with dump_page() showing mapcount:1, but then its raw struct page output showing _mapcount ffffffff i.e. mapcount 0. And even if that particular VM_BUG_ON_PAGE(!unmap_success) is removed, it is immediately followed by a VM_BUG_ON_PAGE(compound_mapcount(head)), and further down an IS_ENABLED(CONFIG_DEBUG_VM) total_mapcount BUG(): all indicative of some mapcount difficulty in development here perhaps. But the !CONFIG_DEBUG_VM path handles the failures correctly and silently. I believe the problem is that once a racing unmap has cleared pte or pmd, try_to_unmap_one() may skip taking the page table lock, and emerge from try_to_unmap() before the racing task has reached decrementing mapcount. Instead of abandoning the unsafe VM_BUG_ON_PAGE(), and the ones that follow, use PVMW_SYNC in try_to_unmap_one() in this case: adding TTU_SYNC to the options, and passing that from unmap_page(). When CONFIG_DEBUG_VM, or for non-debug too? Consensus is to do the same for both: the slight overhead added should rarely matter, except perhaps if splitting sparsely-populated multiply-mapped shmem. Once confident that bugs are fixed, TTU_SYNC here can be removed, and the race tolerated. Link: https://lkml.kernel.org/r/c1e95853-8bcd-d8fd-55fa-e7f2488e78f@google.com Fixes: fec89c109f3a ("thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers") Signed-off-by: Hugh Dickins <hughd(a)google.com> Cc: <stable(a)vger.kernel.org> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Jan Kara <jack(a)suse.cz> Cc: Jue Wang <juew(a)google.com> Cc: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Cc: "Matthew Wilcox (Oracle)" <willy(a)infradead.org> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi(a)nec.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Peter Xu <peterx(a)redhat.com> Cc: Ralph Campbell <rcampbell(a)nvidia.com> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Wang Yugui <wangyugui(a)e16-tech.com> Cc: Yang Shi <shy828301(a)gmail.com> Cc: Zi Yan <ziy(a)nvidia.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/rmap.h | 1 + mm/huge_memory.c | 2 +- mm/page_vma_mapped.c | 11 +++++++++++ mm/rmap.c | 17 ++++++++++++++++- 4 files changed, 29 insertions(+), 2 deletions(-) --- a/include/linux/rmap.h~mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting +++ a/include/linux/rmap.h @@ -91,6 +91,7 @@ enum ttu_flags { TTU_SPLIT_HUGE_PMD = 0x4, /* split huge PMD if any */ TTU_IGNORE_MLOCK = 0x8, /* ignore mlock */ + TTU_SYNC = 0x10, /* avoid racy checks with PVMW_SYNC */ TTU_IGNORE_HWPOISON = 0x20, /* corrupted page is recoverable */ TTU_BATCH_FLUSH = 0x40, /* Batch TLB flushes where possible * and caller guarantees they will --- a/mm/huge_memory.c~mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting +++ a/mm/huge_memory.c @@ -2350,7 +2350,7 @@ void vma_adjust_trans_huge(struct vm_are static void unmap_page(struct page *page) { - enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | + enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_SYNC | TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD; bool unmap_success; --- a/mm/page_vma_mapped.c~mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting +++ a/mm/page_vma_mapped.c @@ -212,6 +212,17 @@ restart: pvmw->ptl = NULL; } } else if (!pmd_present(pmde)) { + /* + * If PVMW_SYNC, take and drop THP pmd lock so that we + * cannot return prematurely, while zap_huge_pmd() has + * cleared *pmd but not decremented compound_mapcount(). + */ + if ((pvmw->flags & PVMW_SYNC) && + PageTransCompound(pvmw->page)) { + spinlock_t *ptl = pmd_lock(mm, pvmw->pmd); + + spin_unlock(ptl); + } return false; } if (!map_pte(pvmw)) --- a/mm/rmap.c~mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting +++ a/mm/rmap.c @@ -1405,6 +1405,15 @@ static bool try_to_unmap_one(struct page struct mmu_notifier_range range; enum ttu_flags flags = (enum ttu_flags)(long)arg; + /* + * When racing against e.g. zap_pte_range() on another cpu, + * in between its ptep_get_and_clear_full() and page_remove_rmap(), + * try_to_unmap() may return false when it is about to become true, + * if page table locking is skipped: use TTU_SYNC to wait for that. + */ + if (flags & TTU_SYNC) + pvmw.flags = PVMW_SYNC; + /* munlock has nothing to gain from examining un-locked vmas */ if ((flags & TTU_MUNLOCK) && !(vma->vm_flags & VM_LOCKED)) return true; @@ -1777,7 +1786,13 @@ bool try_to_unmap(struct page *page, enu else rmap_walk(page, &rwc); - return !page_mapcount(page) ? true : false; + /* + * When racing against e.g. zap_pte_range() on another cpu, + * in between its ptep_get_and_clear_full() and page_remove_rmap(), + * try_to_unmap() may return false when it is about to become true, + * if page table locking is skipped: use TTU_SYNC to wait for that. + */ + return !page_mapcount(page); } /** _ Patches currently in -mm which might be from hughd(a)google.com are mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch mm-page_vma_mapped_walk-use-pmd_read_atomic.patch mm-page_vma_mapped_walk-use-pmde-for-pvmw-pmd.patch mm-page_vma_mapped_walk-prettify-pvmw_migration-block.patch mm-page_vma_mapped_walk-crossing-page-table-boundary.patch mm-page_vma_mapped_walk-add-a-level-of-indentation.patch mm-page_vma_mapped_walk-use-goto-instead-of-while-1.patch mm-page_vma_mapped_walk-get-vma_address_end-earlier.patch mm-thp-fix-page_vma_mapped_walk-if-thp-mapped-by-ptes.patch mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch mm-thp-remap_page-is-only-needed-on-anonymous-thp.patch mm-hwpoison_user_mappings-try_to_unmap-with-ttu_sync.patch

4 years

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+ mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/thp: make is_huge_zero_pmd() safe and quicker has been added to the -mm tree. Its filename is mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-thp-make-is_huge_zero_pmd-safe… and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-make-is_huge_zero_pmd-safe… 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/thp: make is_huge_zero_pmd() safe and quicker Most callers of is_huge_zero_pmd() supply a pmd already verified present; but a few (notably zap_huge_pmd()) do not - it might be a pmd migration entry, in which the pfn is encoded differently from a present pmd: which might pass the is_huge_zero_pmd() test (though not on x86, since L1TF forced us to protect against that); or perhaps even crash in pmd_page() applied to a swap-like entry. Make it safe by adding pmd_present() check into is_huge_zero_pmd() itself; and make it quicker by saving huge_zero_pfn, so that is_huge_zero_pmd() will not need to do that pmd_page() lookup each time. __split_huge_pmd_locked() checked pmd_trans_huge() before: that worked, but is unnecessary now that is_huge_zero_pmd() checks present. Link: https://lkml.kernel.org/r/21ea9ca-a1f5-8b90-5e88-95fb1c49bbfa@google.com Fixes: e71769ae5260 ("mm: enable thp migration for shmem thp") Signed-off-by: Hugh Dickins <hughd(a)google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Reviewed-by: Yang Shi <shy828301(a)gmail.com> Cc: <stable(a)vger.kernel.org> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Jan Kara <jack(a)suse.cz> Cc: Jue Wang <juew(a)google.com> Cc: "Matthew Wilcox (Oracle)" <willy(a)infradead.org> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi(a)nec.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: Peter Xu <peterx(a)redhat.com> Cc: Ralph Campbell <rcampbell(a)nvidia.com> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Wang Yugui <wangyugui(a)e16-tech.com> Cc: Zi Yan <ziy(a)nvidia.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- include/linux/huge_mm.h | 8 +++++++- mm/huge_memory.c | 5 ++++- 2 files changed, 11 insertions(+), 2 deletions(-) --- a/include/linux/huge_mm.h~mm-thp-make-is_huge_zero_pmd-safe-and-quicker +++ a/include/linux/huge_mm.h @@ -286,6 +286,7 @@ struct page *follow_devmap_pud(struct vm vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd); extern struct page *huge_zero_page; +extern unsigned long huge_zero_pfn; static inline bool is_huge_zero_page(struct page *page) { @@ -294,7 +295,7 @@ static inline bool is_huge_zero_page(str static inline bool is_huge_zero_pmd(pmd_t pmd) { - return is_huge_zero_page(pmd_page(pmd)); + return READ_ONCE(huge_zero_pfn) == pmd_pfn(pmd) && pmd_present(pmd); } static inline bool is_huge_zero_pud(pud_t pud) @@ -439,6 +440,11 @@ static inline bool is_huge_zero_page(str { return false; } + +static inline bool is_huge_zero_pmd(pmd_t pmd) +{ + return false; +} static inline bool is_huge_zero_pud(pud_t pud) { --- a/mm/huge_memory.c~mm-thp-make-is_huge_zero_pmd-safe-and-quicker +++ a/mm/huge_memory.c @@ -62,6 +62,7 @@ static struct shrinker deferred_split_sh static atomic_t huge_zero_refcount; struct page *huge_zero_page __read_mostly; +unsigned long huge_zero_pfn __read_mostly = ~0UL; bool transparent_hugepage_enabled(struct vm_area_struct *vma) { @@ -98,6 +99,7 @@ retry: __free_pages(zero_page, compound_order(zero_page)); goto retry; } + WRITE_ONCE(huge_zero_pfn, page_to_pfn(zero_page)); /* We take additional reference here. It will be put back by shrinker */ atomic_set(&huge_zero_refcount, 2); @@ -147,6 +149,7 @@ static unsigned long shrink_huge_zero_pa if (atomic_cmpxchg(&huge_zero_refcount, 1, 0) == 1) { struct page *zero_page = xchg(&huge_zero_page, NULL); BUG_ON(zero_page == NULL); + WRITE_ONCE(huge_zero_pfn, ~0UL); __free_pages(zero_page, compound_order(zero_page)); return HPAGE_PMD_NR; } @@ -2071,7 +2074,7 @@ static void __split_huge_pmd_locked(stru return; } - if (pmd_trans_huge(*pmd) && is_huge_zero_pmd(*pmd)) { + if (is_huge_zero_pmd(*pmd)) { /* * FIXME: Do we want to invalidate secondary mmu by calling * mmu_notifier_invalidate_range() see comments below inside _ Patches currently in -mm which might be from hughd(a)google.com are mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch mm-page_vma_mapped_walk-use-pmd_read_atomic.patch mm-page_vma_mapped_walk-use-pmde-for-pvmw-pmd.patch mm-page_vma_mapped_walk-prettify-pvmw_migration-block.patch mm-page_vma_mapped_walk-crossing-page-table-boundary.patch mm-page_vma_mapped_walk-add-a-level-of-indentation.patch mm-page_vma_mapped_walk-use-goto-instead-of-while-1.patch mm-page_vma_mapped_walk-get-vma_address_end-earlier.patch mm-thp-fix-page_vma_mapped_walk-if-thp-mapped-by-ptes.patch mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch mm-thp-remap_page-is-only-needed-on-anonymous-thp.patch mm-hwpoison_user_mappings-try_to_unmap-with-ttu_sync.patch

4 years

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+ mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch added to -mm tree

by akpm＠linux-foundation.org

The patch titled Subject: mm/thp: fix __split_huge_pmd_locked() on shmem migration entry has been added to the -mm tree. Its filename is mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-thp-fix-__split_huge_pmd_locke… and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-fix-__split_huge_pmd_locke… 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 and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd(a)google.com> Subject: mm/thp: fix __split_huge_pmd_locked() on shmem migration entry Patch series "mm/thp: fix THP splitting unmap BUGs and related", v10. Here is v2 batch of long-standing THP bug fixes that I had not got around to sending before, but prompted now by Wang Yugui's report https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/ Wang Yugui has tested a rollup of these fixes applied to 5.10.39, and they have done no harm, but have *not* fixed that issue: something more is needed and I have no idea of what. This patch (of 7): Stressing huge tmpfs page migration racing hole punch often crashed on the VM_BUG_ON(!pmd_present) in pmdp_huge_clear_flush(), with DEBUG_VM=y kernel; or shortly afterwards, on a bad dereference in __split_huge_pmd_locked() when DEBUG_VM=n. They forgot to allow for pmd migration entries in the non-anonymous case. Full disclosure: those particular experiments were on a kernel with more relaxed mmap_lock and i_mmap_rwsem locking, and were not repeated on the vanilla kernel: it is conceivable that stricter locking happens to avoid those cases, or makes them less likely; but __split_huge_pmd_locked() already allowed for pmd migration entries when handling anonymous THPs, so this commit brings the shmem and file THP handling into line. And while there: use old_pmd rather than _pmd, as in the following blocks; and make it clearer to the eye that the !vma_is_anonymous() block is self-contained, making an early return after accounting for unmapping. Link: https://lkml.kernel.org/r/af88612-1473-2eaa-903-8d1a448b26@google.com Link: https://lkml.kernel.org/r/dd221a99-efb3-cd1d-6256-7e646af29314@google.com Fixes: e71769ae5260 ("mm: enable thp migration for shmem thp") Signed-off-by: Hugh Dickins <hughd(a)google.com> Cc: Kirill A. Shutemov <kirill.shutemov(a)linux.intel.com> Cc: Yang Shi <shy828301(a)gmail.com> Cc: Wang Yugui <wangyugui(a)e16-tech.com> Cc: "Matthew Wilcox (Oracle)" <willy(a)infradead.org> Cc: Naoya Horiguchi <naoya.horiguchi(a)nec.com> Cc: Alistair Popple <apopple(a)nvidia.com> Cc: Ralph Campbell <rcampbell(a)nvidia.com> Cc: Zi Yan <ziy(a)nvidia.com> Cc: Miaohe Lin <linmiaohe(a)huawei.com> Cc: Minchan Kim <minchan(a)kernel.org> Cc: Jue Wang <juew(a)google.com> Cc: Peter Xu <peterx(a)redhat.com> Cc: Jan Kara <jack(a)suse.cz> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Oscar Salvador <osalvador(a)suse.de> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- mm/huge_memory.c | 27 ++++++++++++++++++--------- mm/pgtable-generic.c | 5 ++--- 2 files changed, 20 insertions(+), 12 deletions(-) --- a/mm/huge_memory.c~mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry +++ a/mm/huge_memory.c @@ -2044,7 +2044,7 @@ static void __split_huge_pmd_locked(stru count_vm_event(THP_SPLIT_PMD); if (!vma_is_anonymous(vma)) { - _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); + old_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd); /* * We are going to unmap this huge page. So * just go ahead and zap it @@ -2053,16 +2053,25 @@ static void __split_huge_pmd_locked(stru zap_deposited_table(mm, pmd); if (vma_is_special_huge(vma)) return; - page = pmd_page(_pmd); - if (!PageDirty(page) && pmd_dirty(_pmd)) - set_page_dirty(page); - if (!PageReferenced(page) && pmd_young(_pmd)) - SetPageReferenced(page); - page_remove_rmap(page, true); - put_page(page); + if (unlikely(is_pmd_migration_entry(old_pmd))) { + swp_entry_t entry; + + entry = pmd_to_swp_entry(old_pmd); + page = migration_entry_to_page(entry); + } else { + page = pmd_page(old_pmd); + if (!PageDirty(page) && pmd_dirty(old_pmd)) + set_page_dirty(page); + if (!PageReferenced(page) && pmd_young(old_pmd)) + SetPageReferenced(page); + page_remove_rmap(page, true); + put_page(page); + } add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR); return; - } else if (pmd_trans_huge(*pmd) && is_huge_zero_pmd(*pmd)) { + } + + if (pmd_trans_huge(*pmd) && is_huge_zero_pmd(*pmd)) { /* * FIXME: Do we want to invalidate secondary mmu by calling * mmu_notifier_invalidate_range() see comments below inside --- a/mm/pgtable-generic.c~mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry +++ a/mm/pgtable-generic.c @@ -135,9 +135,8 @@ pmd_t pmdp_huge_clear_flush(struct vm_ar { pmd_t pmd; VM_BUG_ON(address & ~HPAGE_PMD_MASK); - VM_BUG_ON(!pmd_present(*pmdp)); - /* Below assumes pmd_present() is true */ - VM_BUG_ON(!pmd_trans_huge(*pmdp) && !pmd_devmap(*pmdp)); + VM_BUG_ON(pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) && + !pmd_devmap(*pmdp)); pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp); flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); return pmd; _ Patches currently in -mm which might be from hughd(a)google.com are mm-thp-fix-__split_huge_pmd_locked-on-shmem-migration-entry.patch mm-thp-make-is_huge_zero_pmd-safe-and-quicker.patch mm-thp-try_to_unmap-use-ttu_sync-for-safe-splitting.patch mm-thp-fix-vma_address-if-virtual-address-below-file-offset.patch mm-thp-unmap_mapping_page-to-fix-thp-truncate_cleanup_page.patch mm-page_vma_mapped_walk-use-page-for-pvmw-page.patch mm-page_vma_mapped_walk-settle-pagehuge-on-entry.patch mm-page_vma_mapped_walk-use-pmd_read_atomic.patch mm-page_vma_mapped_walk-use-pmde-for-pvmw-pmd.patch mm-page_vma_mapped_walk-prettify-pvmw_migration-block.patch mm-page_vma_mapped_walk-crossing-page-table-boundary.patch mm-page_vma_mapped_walk-add-a-level-of-indentation.patch mm-page_vma_mapped_walk-use-goto-instead-of-while-1.patch mm-page_vma_mapped_walk-get-vma_address_end-earlier.patch mm-thp-fix-page_vma_mapped_walk-if-thp-mapped-by-ptes.patch mm-thp-another-pvmw_sync-fix-in-page_vma_mapped_walk.patch mm-thp-remap_page-is-only-needed-on-anonymous-thp.patch mm-hwpoison_user_mappings-try_to_unmap-with-ttu_sync.patch

4 years

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[PATCH 4.19 1/2] perf/cgroups: Don't rotate events for cgroups unnecessarily

by Wen Yang

From: Ian Rogers <irogers(a)google.com> [ Upstream commit fd7d55172d1e2e501e6da0a5c1de25f06612dc2e ] Currently perf_rotate_context assumes that if the context's nr_events != nr_active a rotation is necessary for perf event multiplexing. With cgroups, nr_events is the total count of events for all cgroups and nr_active will not include events in a cgroup other than the current task's. This makes rotation appear necessary for cgroups when it is not. Add a perf_event_context flag that is set when rotation is necessary. Clear the flag during sched_out and set it when a flexible sched_in fails due to resources. Signed-off-by: Ian Rogers <irogers(a)google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org> Cc: Alexander Shishkin <alexander.shishkin(a)linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme(a)kernel.org> Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com> Cc: Borislav Petkov <bp(a)alien8.de> Cc: Jiri Olsa <jolsa(a)redhat.com> Cc: Kan Liang <kan.liang(a)linux.intel.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Namhyung Kim <namhyung(a)kernel.org> Cc: Peter Zijlstra <peterz(a)infradead.org> Cc: Stephane Eranian <eranian(a)google.com> Cc: Thomas Gleixner <tglx(a)linutronix.de> Cc: Vince Weaver <vincent.weaver(a)maine.edu> Link: https://lkml.kernel.org/r/20190601082722.44543-1-irogers@google.com Signed-off-by: Ingo Molnar <mingo(a)kernel.org> Cc: stable(a)vger.kernel.org # 4.19+ Signed-off-by: Wen Yang <wenyang(a)linux.alibaba.com> --- include/linux/perf_event.h | 5 +++++ kernel/events/core.c | 42 ++++++++++++++++++++++-------------------- 2 files changed, 27 insertions(+), 20 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index d8b4d31..efe30b9 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -747,6 +747,11 @@ struct perf_event_context { int nr_stat; int nr_freq; int rotate_disable; + /* + * Set when nr_events != nr_active, except tolerant to events not + * necessary to be active due to scheduling constraints, such as cgroups. + */ + int rotate_necessary; atomic_t refcount; struct task_struct *task; diff --git a/kernel/events/core.c b/kernel/events/core.c index b8b74a4..56e3789 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2952,6 +2952,12 @@ static void ctx_sched_out(struct perf_event_context *ctx, if (!ctx->nr_active || !(is_active & EVENT_ALL)) return; + /* + * If we had been multiplexing, no rotations are necessary, now no events + * are active. + */ + ctx->rotate_necessary = 0; + perf_pmu_disable(ctx->pmu); if (is_active & EVENT_PINNED) { list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list) @@ -3319,10 +3325,13 @@ static int flexible_sched_in(struct perf_event *event, void *data) return 0; if (group_can_go_on(event, sid->cpuctx, sid->can_add_hw)) { - if (!group_sched_in(event, sid->cpuctx, sid->ctx)) - list_add_tail(&event->active_list, &sid->ctx->flexible_active); - else + int ret = group_sched_in(event, sid->cpuctx, sid->ctx); + if (ret) { sid->can_add_hw = 0; + sid->ctx->rotate_necessary = 1; + return 0; + } + list_add_tail(&event->active_list, &sid->ctx->flexible_active); } return 0; @@ -3690,24 +3699,17 @@ static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event) static bool perf_rotate_context(struct perf_cpu_context *cpuctx) { struct perf_event *cpu_event = NULL, *task_event = NULL; - bool cpu_rotate = false, task_rotate = false; - struct perf_event_context *ctx = NULL; + struct perf_event_context *task_ctx = NULL; + int cpu_rotate, task_rotate; /* * Since we run this from IRQ context, nobody can install new * events, thus the event count values are stable. */ - if (cpuctx->ctx.nr_events) { - if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active) - cpu_rotate = true; - } - - ctx = cpuctx->task_ctx; - if (ctx && ctx->nr_events) { - if (ctx->nr_events != ctx->nr_active) - task_rotate = true; - } + cpu_rotate = cpuctx->ctx.rotate_necessary; + task_ctx = cpuctx->task_ctx; + task_rotate = task_ctx ? task_ctx->rotate_necessary : 0; if (!(cpu_rotate || task_rotate)) return false; @@ -3716,7 +3718,7 @@ static bool perf_rotate_context(struct perf_cpu_context *cpuctx) perf_pmu_disable(cpuctx->ctx.pmu); if (task_rotate) - task_event = ctx_first_active(ctx); + task_event = ctx_first_active(task_ctx); if (cpu_rotate) cpu_event = ctx_first_active(&cpuctx->ctx); @@ -3724,17 +3726,17 @@ static bool perf_rotate_context(struct perf_cpu_context *cpuctx) * As per the order given at ctx_resched() first 'pop' task flexible * and then, if needed CPU flexible. */ - if (task_event || (ctx && cpu_event)) - ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE); + if (task_event || (task_ctx && cpu_event)) + ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE); if (cpu_event) cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE); if (task_event) - rotate_ctx(ctx, task_event); + rotate_ctx(task_ctx, task_event); if (cpu_event) rotate_ctx(&cpuctx->ctx, cpu_event); - perf_event_sched_in(cpuctx, ctx, current); + perf_event_sched_in(cpuctx, task_ctx, current); perf_pmu_enable(cpuctx->ctx.pmu); perf_ctx_unlock(cpuctx, cpuctx->task_ctx); -- 1.8.3.1

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Linux-stable-mirror June 2021