From 9710a78ab2aed09690edf34a5c82f5107f448946 Mon Sep 17 00:00:00 2001 From: Zach O'Keefe Date: Wed, 6 Jul 2022 16:59:22 -0700 Subject: [PATCH] mm/khugepaged: dedup and simplify hugepage alloc and charging The following code is duplicated in collapse_huge_page() and collapse_file(): gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE; new_page = khugepaged_alloc_page(hpage, gfp, node); if (!new_page) { result = SCAN_ALLOC_HUGE_PAGE_FAIL; goto out; } if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) { result = SCAN_CGROUP_CHARGE_FAIL; goto out; } count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC); Also, "node" is passed as an argument to both collapse_huge_page() and collapse_file() and obtained the same way, via khugepaged_find_target_node(). Move all this into a new helper, alloc_charge_hpage(), and remove the duplicate code from collapse_huge_page() and collapse_file(). Also, simplify khugepaged_alloc_page() by returning a bool indicating allocation success instead of a copy of the allocated struct page *. Link: https://lkml.kernel.org/r/20220706235936.2197195-5-zokeefe@google.com Signed-off-by: Zach O'Keefe Suggested-by: Peter Xu Acked-by: David Rientjes 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: 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: 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 --- mm/khugepaged.c | 78 ++++++++++++++++++++++--------------------------- 1 file changed, 35 insertions(+), 43 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index ee419598d0e6..c0133816a3fa 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -813,19 +813,18 @@ static int khugepaged_find_target_node(struct collapse_control *cc) } #endif -static struct page * -khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node) +static bool khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node) { *hpage = __alloc_pages_node(node, gfp, HPAGE_PMD_ORDER); if (unlikely(!*hpage)) { count_vm_event(THP_COLLAPSE_ALLOC_FAILED); *hpage = ERR_PTR(-ENOMEM); - return NULL; + return false; } prep_transhuge_page(*hpage); count_vm_event(THP_COLLAPSE_ALLOC); - return *hpage; + return true; } /* @@ -923,10 +922,24 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm, return true; } -static void collapse_huge_page(struct mm_struct *mm, - unsigned long address, - struct page **hpage, - int node, int referenced, int unmapped) +static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm, + struct collapse_control *cc) +{ + /* Only allocate from the target node */ + gfp_t gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE; + int node = khugepaged_find_target_node(cc); + + if (!khugepaged_alloc_page(hpage, gfp, node)) + return SCAN_ALLOC_HUGE_PAGE_FAIL; + if (unlikely(mem_cgroup_charge(page_folio(*hpage), mm, gfp))) + return SCAN_CGROUP_CHARGE_FAIL; + count_memcg_page_event(*hpage, THP_COLLAPSE_ALLOC); + return SCAN_SUCCEED; +} + +static void collapse_huge_page(struct mm_struct *mm, unsigned long address, + struct page **hpage, int referenced, + int unmapped, struct collapse_control *cc) { LIST_HEAD(compound_pagelist); pmd_t *pmd, _pmd; @@ -937,13 +950,9 @@ static void collapse_huge_page(struct mm_struct *mm, int isolated = 0, result = 0; struct vm_area_struct *vma; struct mmu_notifier_range range; - gfp_t gfp; VM_BUG_ON(address & ~HPAGE_PMD_MASK); - /* Only allocate from the target node */ - gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE; - /* * Before allocating the hugepage, release the mmap_lock read lock. * The allocation can take potentially a long time if it involves @@ -951,17 +960,12 @@ static void collapse_huge_page(struct mm_struct *mm, * that. We will recheck the vma after taking it again in write mode. */ mmap_read_unlock(mm); - new_page = khugepaged_alloc_page(hpage, gfp, node); - if (!new_page) { - result = SCAN_ALLOC_HUGE_PAGE_FAIL; - goto out_nolock; - } - if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) { - result = SCAN_CGROUP_CHARGE_FAIL; + result = alloc_charge_hpage(hpage, mm, cc); + if (result != SCAN_SUCCEED) goto out_nolock; - } - count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC); + + new_page = *hpage; mmap_read_lock(mm); result = hugepage_vma_revalidate(mm, address, &vma); @@ -1235,10 +1239,9 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, struct vm_area_struct *vma, out_unmap: pte_unmap_unlock(pte, ptl); if (ret) { - node = khugepaged_find_target_node(cc); /* collapse_huge_page will return with the mmap_lock released */ - collapse_huge_page(mm, address, hpage, node, - referenced, unmapped); + collapse_huge_page(mm, address, hpage, referenced, unmapped, + cc); } out: trace_mm_khugepaged_scan_pmd(mm, page, writable, referenced, @@ -1506,7 +1509,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) * @file: file that collapse on * @start: collapse start address * @hpage: new allocated huge page for collapse - * @node: appointed node the new huge page allocate from + * @cc: collapse context and scratchpad * * Basic scheme is simple, details are more complex: * - allocate and lock a new huge page; @@ -1523,12 +1526,11 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) * + restore gaps in the page cache; * + unlock and free huge page; */ -static void collapse_file(struct mm_struct *mm, - struct file *file, pgoff_t start, - struct page **hpage, int node) +static void collapse_file(struct mm_struct *mm, struct file *file, + pgoff_t start, struct page **hpage, + struct collapse_control *cc) { struct address_space *mapping = file->f_mapping; - gfp_t gfp; struct page *new_page; pgoff_t index, end = start + HPAGE_PMD_NR; LIST_HEAD(pagelist); @@ -1540,20 +1542,11 @@ static void collapse_file(struct mm_struct *mm, VM_BUG_ON(!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !is_shmem); VM_BUG_ON(start & (HPAGE_PMD_NR - 1)); - /* Only allocate from the target node */ - gfp = alloc_hugepage_khugepaged_gfpmask() | __GFP_THISNODE; - - new_page = khugepaged_alloc_page(hpage, gfp, node); - if (!new_page) { - result = SCAN_ALLOC_HUGE_PAGE_FAIL; + result = alloc_charge_hpage(hpage, mm, cc); + if (result != SCAN_SUCCEED) goto out; - } - if (unlikely(mem_cgroup_charge(page_folio(new_page), mm, gfp))) { - result = SCAN_CGROUP_CHARGE_FAIL; - goto out; - } - count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC); + new_page = *hpage; /* * Ensure we have slots for all the pages in the range. This is @@ -1965,8 +1958,7 @@ static void khugepaged_scan_file(struct mm_struct *mm, struct file *file, result = SCAN_EXCEED_NONE_PTE; count_vm_event(THP_SCAN_EXCEED_NONE_PTE); } else { - node = khugepaged_find_target_node(cc); - collapse_file(mm, file, start, hpage, node); + collapse_file(mm, file, start, hpage, cc); } }