From: Zach O'Keefe Date: Wed, 6 Jul 2022 23:59:25 +0000 (-0700) Subject: mm/thp: add flag to enforce sysfs THP in hugepage_vma_check() X-Git-Tag: howlett/maple/20220722_2~42 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=dccd751c7dde08a9b1c3e00c0bac814eff00e3cc;p=users%2Fjedix%2Flinux-maple.git mm/thp: add flag to enforce sysfs THP in hugepage_vma_check() MADV_COLLAPSE is not coupled to the kernel-oriented sysfs THP settings[1]. hugepage_vma_check() is the authority on determining if a VMA is eligible for THP allocation/collapse, and currently enforces the sysfs THP settings. Add a flag to disable these checks. For now, only apply this arg to anon and file, which use /sys/kernel/transparent_hugepage/enabled. We can expand this to shmem, which uses /sys/kernel/transparent_hugepage/shmem_enabled, later. Use this flag in collapse_pte_mapped_thp() where previously the VMA flags passed to hugepage_vma_check() were OR'd with VM_HUGEPAGE to elide the VM_HUGEPAGE check in "madvise" THP mode. Prior to "mm: khugepaged: check THP flag in hugepage_vma_check()", this check also didn't check "never" THP mode. As such, this restores the previous behavior of collapse_pte_mapped_thp() where sysfs THP settings are ignored. See comment in code for justification why this is OK. [1] https://lore.kernel.org/linux-mm/CAAa6QmQxay1_=Pmt8oCX2-Va18t44FV-Vs-WsQt_6+qBks4nZA@mail.gmail.com/ Link: https://lkml.kernel.org/r/20220706235936.2197195-8-zokeefe@google.com Signed-off-by: Zach O'Keefe Reviewed-by: Yang Shi Cc: Alex Shi Cc: Andrea Arcangeli Cc: Arnd Bergmann Cc: Axel Rasmussen Cc: Chris Kennelly Cc: Chris Zankel Cc: David Hildenbrand Cc: David Rientjes Cc: Helge Deller Cc: Hugh Dickins Cc: Ivan Kokshaysky Cc: James Bottomley Cc: Jens Axboe Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Matt Turner Cc: Max Filippov Cc: Miaohe Lin Cc: Michal Hocko Cc: Minchan Kim Cc: Pasha Tatashin Cc: Pavel Begunkov Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Thomas Bogendoerfer Cc: Vlastimil Babka Cc: Zi Yan Cc: Dan Carpenter Cc: "Souptick Joarder (HPE)" Signed-off-by: Andrew Morton --- diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 34d292cec79a..f8cd58846a28 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -866,7 +866,7 @@ static int show_smap(struct seq_file *m, void *v) __show_smap(m, &mss, false); seq_printf(m, "THPeligible: %d\n", - hugepage_vma_check(vma, vma->vm_flags, true, false)); + hugepage_vma_check(vma, vma->vm_flags, true, false, true)); if (arch_pkeys_enabled()) seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma)); diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 37f2f11a6d7e..00312fc251c1 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -168,9 +168,8 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma) !inode_is_open_for_write(inode) && S_ISREG(inode->i_mode); } -bool hugepage_vma_check(struct vm_area_struct *vma, - unsigned long vm_flags, - bool smaps, bool in_pf); +bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, + bool smaps, bool in_pf, bool enforce_sysfs); #define transparent_hugepage_use_zero_page() \ (transparent_hugepage_flags & \ @@ -321,8 +320,8 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma, } static inline bool hugepage_vma_check(struct vm_area_struct *vma, - unsigned long vm_flags, - bool smaps, bool in_pf) + unsigned long vm_flags, bool smaps, + bool in_pf, bool enforce_sysfs) { return false; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9f70582b8f51..0dfc67dec108 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -69,9 +69,8 @@ static atomic_t huge_zero_refcount; struct page *huge_zero_page __read_mostly; unsigned long huge_zero_pfn __read_mostly = ~0UL; -bool hugepage_vma_check(struct vm_area_struct *vma, - unsigned long vm_flags, - bool smaps, bool in_pf) +bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, + bool smaps, bool in_pf, bool enforce_sysfs) { if (!vma->vm_mm) /* vdso */ return false; @@ -120,11 +119,10 @@ bool hugepage_vma_check(struct vm_area_struct *vma, if (!in_pf && shmem_file(vma->vm_file)) return shmem_huge_enabled(vma); - if (!hugepage_flags_enabled()) - return false; - - /* THP settings require madvise. */ - if (!(vm_flags & VM_HUGEPAGE) && !hugepage_flags_always()) + /* Enforce sysfs THP requirements as necessary */ + if (enforce_sysfs && + (!hugepage_flags_enabled() || (!(vm_flags & VM_HUGEPAGE) && + !hugepage_flags_always()))) return false; /* Only regular file is valid */ diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 3128c7fe9742..c2188745982c 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -481,7 +481,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma, { if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) && hugepage_flags_enabled()) { - if (hugepage_vma_check(vma, vm_flags, false, false)) + if (hugepage_vma_check(vma, vm_flags, false, false, true)) __khugepaged_enter(vma->vm_mm); } } @@ -847,7 +847,8 @@ static bool khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node) */ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, - struct vm_area_struct **vmap) + struct vm_area_struct **vmap, + struct collapse_control *cc) { struct vm_area_struct *vma; @@ -860,7 +861,8 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address, if (!transhuge_vma_suitable(vma, address)) return SCAN_ADDRESS_RANGE; - if (!hugepage_vma_check(vma, vma->vm_flags, false, false)) + if (!hugepage_vma_check(vma, vma->vm_flags, false, false, + cc->is_khugepaged)) return SCAN_VMA_CHECK; /* * Anon VMA expected, the address may be unmapped then @@ -979,7 +981,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, goto out_nolock; mmap_read_lock(mm); - result = hugepage_vma_revalidate(mm, address, &vma); + result = hugepage_vma_revalidate(mm, address, &vma, cc); if (result != SCAN_SUCCEED) { mmap_read_unlock(mm); goto out_nolock; @@ -1011,7 +1013,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, * handled by the anon_vma lock + PG_lock. */ mmap_write_lock(mm); - result = hugepage_vma_revalidate(mm, address, &vma); + result = hugepage_vma_revalidate(mm, address, &vma, cc); if (result != SCAN_SUCCEED) goto out_up_write; /* check if the pmd is still valid */ @@ -1355,12 +1357,13 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) return; /* - * This vm_flags may not have VM_HUGEPAGE if the page was not - * collapsed by this mm. But we can still collapse if the page is - * the valid THP. Add extra VM_HUGEPAGE so hugepage_vma_check() - * will not fail the vma for missing VM_HUGEPAGE + * If we are here, we've succeeded in replacing all the native pages + * in the page cache with a single hugepage. If a mm were to fault-in + * this memory (mapped by a suitably aligned VMA), we'd get the hugepage + * and map it by a PMD, regardless of sysfs THP settings. As such, let's + * analogously elide sysfs THP settings here. */ - if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false, false)) + if (!hugepage_vma_check(vma, vma->vm_flags, false, false, false)) return; /* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */ @@ -2047,7 +2050,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result, progress++; break; } - if (!hugepage_vma_check(vma, vma->vm_flags, false, false)) { + if (!hugepage_vma_check(vma, vma->vm_flags, false, false, true)) { skip: progress++; continue; diff --git a/mm/memory.c b/mm/memory.c index 57480ce3dbc1..aa7c7e15abe4 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5004,7 +5004,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, return VM_FAULT_OOM; retry_pud: if (pud_none(*vmf.pud) && - hugepage_vma_check(vma, vm_flags, false, true)) { + hugepage_vma_check(vma, vm_flags, false, true, true)) { ret = create_huge_pud(&vmf); if (!(ret & VM_FAULT_FALLBACK)) return ret; @@ -5038,7 +5038,7 @@ retry_pud: goto retry_pud; if (pmd_none(*vmf.pmd) && - hugepage_vma_check(vma, vm_flags, false, true)) { + hugepage_vma_check(vma, vm_flags, false, true, true)) { ret = create_huge_pmd(&vmf); if (!(ret & VM_FAULT_FALLBACK)) return ret;