From ae859762332f19bfc06f4c4a1b1fefb41e9e1084 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Sat, 29 Oct 2005 18:16:05 -0700 Subject: [PATCH] [PATCH] mm: batch updating mm_counters tlb_finish_mmu used to batch zap_pte_range's update of mm rss, which may be worthwhile if the mm is contended, and would reduce atomic operations if the counts were atomic. Let zap_pte_range now batch its updates to file_rss and anon_rss, per page-table in case we drop the lock outside; and copy_pte_range batch them too. Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory.c | 47 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 32 insertions(+), 15 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 59d42e50fa53..da642b5528fa 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -332,6 +332,16 @@ pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned lon return pte_offset_kernel(pmd, address); } +static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) +{ + if (file_rss) + add_mm_counter(mm, file_rss, file_rss); + if (anon_rss) + add_mm_counter(mm, anon_rss, anon_rss); +} + +#define NO_RSS 2 /* Increment neither file_rss nor anon_rss */ + /* * copy one vm_area from one task to the other. Assumes the page tables * already present in the new task to be cleared in the whole range @@ -341,7 +351,7 @@ pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned lon * but may be dropped within p[mg]d_alloc() and pte_alloc_map(). */ -static inline void +static inline int copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, pte_t *dst_pte, pte_t *src_pte, unsigned long vm_flags, unsigned long addr) @@ -349,6 +359,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, pte_t pte = *src_pte; struct page *page; unsigned long pfn; + int anon = NO_RSS; /* pte contains position in swap or file, so copy. */ if (unlikely(!pte_present(pte))) { @@ -361,8 +372,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, spin_unlock(&mmlist_lock); } } - set_pte_at(dst_mm, addr, dst_pte, pte); - return; + goto out_set_pte; } pfn = pte_pfn(pte); @@ -375,10 +385,8 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, if (pfn_valid(pfn)) page = pfn_to_page(pfn); - if (!page || PageReserved(page)) { - set_pte_at(dst_mm, addr, dst_pte, pte); - return; - } + if (!page || PageReserved(page)) + goto out_set_pte; /* * If it's a COW mapping, write protect it both @@ -397,12 +405,12 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, pte = pte_mkclean(pte); pte = pte_mkold(pte); get_page(page); - if (PageAnon(page)) - inc_mm_counter(dst_mm, anon_rss); - else - inc_mm_counter(dst_mm, file_rss); - set_pte_at(dst_mm, addr, dst_pte, pte); page_dup_rmap(page); + anon = !!PageAnon(page); + +out_set_pte: + set_pte_at(dst_mm, addr, dst_pte, pte); + return anon; } static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, @@ -412,8 +420,10 @@ static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, pte_t *src_pte, *dst_pte; unsigned long vm_flags = vma->vm_flags; int progress = 0; + int rss[NO_RSS+1], anon; again: + rss[1] = rss[0] = 0; dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr); if (!dst_pte) return -ENOMEM; @@ -436,13 +446,16 @@ static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, progress++; continue; } - copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vm_flags, addr); + anon = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, + vm_flags, addr); + rss[anon]++; progress += 8; } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); spin_unlock(&src_mm->page_table_lock); pte_unmap_nested(src_pte - 1); pte_unmap(dst_pte - 1); + add_mm_rss(dst_mm, rss[0], rss[1]); cond_resched_lock(&dst_mm->page_table_lock); if (addr != end) goto again; @@ -533,6 +546,8 @@ static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd, struct zap_details *details) { pte_t *pte; + int file_rss = 0; + int anon_rss = 0; pte = pte_offset_map(pmd, addr); do { @@ -576,13 +591,13 @@ static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd, set_pte_at(tlb->mm, addr, pte, pgoff_to_pte(page->index)); if (PageAnon(page)) - dec_mm_counter(tlb->mm, anon_rss); + anon_rss++; else { if (pte_dirty(ptent)) set_page_dirty(page); if (pte_young(ptent)) mark_page_accessed(page); - dec_mm_counter(tlb->mm, file_rss); + file_rss++; } page_remove_rmap(page); tlb_remove_page(tlb, page); @@ -598,6 +613,8 @@ static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd, free_swap_and_cache(pte_to_swp_entry(ptent)); pte_clear_full(tlb->mm, addr, pte, tlb->fullmm); } while (pte++, addr += PAGE_SIZE, addr != end); + + add_mm_rss(tlb->mm, -file_rss, -anon_rss); pte_unmap(pte - 1); }