From 97a7e4733b9b221d012ae68fcd3b3251febf6341 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Fri, 12 Mar 2021 21:07:26 -0800 Subject: mm: introduce page_needs_cow_for_dma() for deciding whether cow We've got quite a few places (pte, pmd, pud) that explicitly checked against whether we should break the cow right now during fork(). It's easier to provide a helper, especially before we work the same thing on hugetlbfs. Since we'll reference is_cow_mapping() in mm.h, move it there too. Actually it suites mm.h more since internal.h is mm/ only, but mm.h is exported to the whole kernel. With that we should expect another patch to use is_cow_mapping() whenever we can across the kernel since we do use it quite a lot but it's always done with raw code against VM_* flags. Link: https://lkml.kernel.org/r/20210217233547.93892-4-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: Jason Gunthorpe Cc: Alexey Dobriyan Cc: Andrea Arcangeli Cc: Christoph Hellwig Cc: Daniel Vetter Cc: David Airlie Cc: David Gibson Cc: Gal Pressman Cc: Jan Kara Cc: Jann Horn Cc: Kirill Shutemov Cc: Kirill Tkhai Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Mike Kravetz Cc: Mike Rapoport Cc: Roland Scheidegger Cc: VMware Graphics Cc: Wei Zhang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/huge_memory.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'mm/huge_memory.c') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 395c75111d33..da1d63a41aec 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1100,9 +1100,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, * best effort that the pinned pages won't be replaced by another * random page during the coming copy-on-write. */ - if (unlikely(is_cow_mapping(vma->vm_flags) && - atomic_read(&src_mm->has_pinned) && - page_maybe_dma_pinned(src_page))) { + if (unlikely(page_needs_cow_for_dma(vma, src_page))) { pte_free(dst_mm, pgtable); spin_unlock(src_ptl); spin_unlock(dst_ptl); @@ -1214,9 +1212,7 @@ int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, } /* Please refer to comments in copy_huge_pmd() */ - if (unlikely(is_cow_mapping(vma->vm_flags) && - atomic_read(&src_mm->has_pinned) && - page_maybe_dma_pinned(pud_page(pud)))) { + if (unlikely(page_needs_cow_for_dma(vma, pud_page(pud)))) { spin_unlock(src_ptl); spin_unlock(dst_ptl); __split_huge_pud(vma, src_pud, addr); -- cgit v1.2.3 From be6c8982e4ab9a41907555f601b711a7e2a17d4c Mon Sep 17 00:00:00 2001 From: Zhou Guanghui Date: Fri, 12 Mar 2021 21:08:30 -0800 Subject: mm/memcg: rename mem_cgroup_split_huge_fixup to split_page_memcg and add nr_pages argument Rename mem_cgroup_split_huge_fixup to split_page_memcg and explicitly pass in page number argument. In this way, the interface name is more common and can be used by potential users. In addition, the complete info(memcg and flag) of the memcg needs to be set to the tail pages. Link: https://lkml.kernel.org/r/20210304074053.65527-2-zhouguanghui1@huawei.com Signed-off-by: Zhou Guanghui Acked-by: Johannes Weiner Reviewed-by: Zi Yan Reviewed-by: Shakeel Butt Acked-by: Michal Hocko Cc: Hugh Dickins Cc: "Kirill A. Shutemov" Cc: Nicholas Piggin Cc: Kefeng Wang Cc: Hanjun Guo Cc: Tianhong Ding Cc: Weilong Chen Cc: Rui Xiang Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 6 ++---- mm/huge_memory.c | 2 +- mm/memcontrol.c | 15 ++++++--------- 3 files changed, 9 insertions(+), 14 deletions(-) (limited to 'mm/huge_memory.c') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index e6dc793d587d..0c04d39a7967 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1061,9 +1061,7 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm, rcu_read_unlock(); } -#ifdef CONFIG_TRANSPARENT_HUGEPAGE -void mem_cgroup_split_huge_fixup(struct page *head); -#endif +void split_page_memcg(struct page *head, unsigned int nr); #else /* CONFIG_MEMCG */ @@ -1400,7 +1398,7 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, return 0; } -static inline void mem_cgroup_split_huge_fixup(struct page *head) +static inline void split_page_memcg(struct page *head, unsigned int nr) { } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index da1d63a41aec..ae907a9c2050 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2467,7 +2467,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, int i; /* complete memcg works before add pages to LRU */ - mem_cgroup_split_huge_fixup(head); + split_page_memcg(head, nr); if (PageAnon(head) && PageSwapCache(head)) { swp_entry_t entry = { .val = page_private(head) }; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 845eec01ef9d..e064ac0d850a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3287,24 +3287,21 @@ void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size) #endif /* CONFIG_MEMCG_KMEM */ -#ifdef CONFIG_TRANSPARENT_HUGEPAGE /* - * Because page_memcg(head) is not set on compound tails, set it now. + * Because page_memcg(head) is not set on tails, set it now. */ -void mem_cgroup_split_huge_fixup(struct page *head) +void split_page_memcg(struct page *head, unsigned int nr) { struct mem_cgroup *memcg = page_memcg(head); int i; - if (mem_cgroup_disabled()) + if (mem_cgroup_disabled() || !memcg) return; - for (i = 1; i < HPAGE_PMD_NR; i++) { - css_get(&memcg->css); - head[i].memcg_data = (unsigned long)memcg; - } + for (i = 1; i < nr; i++) + head[i].memcg_data = head->memcg_data; + css_get_many(&memcg->css, nr - 1); } -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #ifdef CONFIG_MEMCG_SWAP /** -- cgit v1.2.3