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Date: Wed, 4 Mar 2020 16:17:32 +0800 From: "Huang, Ying" <ying.huang@...el.com> To: Andrew Morton <akpm@...ux-foundation.org> Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org, Huang Ying <ying.huang@...el.com>, Dave Hansen <dave.hansen@...ux.intel.com>, David Hildenbrand <david@...hat.com>, Mel Gorman <mgorman@...e.de>, Vlastimil Babka <vbabka@...e.cz>, Zi Yan <ziy@...dia.com>, Michal Hocko <mhocko@...nel.org>, Peter Zijlstra <peterz@...radead.org>, Minchan Kim <minchan@...nel.org>, Johannes Weiner <hannes@...xchg.org>, Hugh Dickins <hughd@...gle.com> Subject: [PATCH -V2] mm: Add PageLayzyFree() helper functions for MADV_FREE From: Huang Ying <ying.huang@...el.com> Now PageSwapBacked() is used as the helper function to check whether pages have been freed lazily via MADV_FREE. This isn't very obvious. So Dave suggested to add PageLazyFree() family helper functions to improve the code readability. Signed-off-by: "Huang, Ying" <ying.huang@...el.com> Suggested-by: Dave Hansen <dave.hansen@...ux.intel.com> Cc: David Hildenbrand <david@...hat.com> Cc: Mel Gorman <mgorman@...e.de> Cc: Vlastimil Babka <vbabka@...e.cz> Cc: Zi Yan <ziy@...dia.com> Cc: Michal Hocko <mhocko@...nel.org> Cc: Peter Zijlstra <peterz@...radead.org> Cc: Minchan Kim <minchan@...nel.org> Cc: Johannes Weiner <hannes@...xchg.org> Cc: Hugh Dickins <hughd@...gle.com> --- Changelog: v2: - Avoid code bloat via removing VM_BUG_ON_PAGE(), which doesn't exist in the original code. Now there is no any text/data/bss size change. - Fix one wrong replacement in try_to_unmap_one(). --- include/linux/page-flags.h | 25 +++++++++++++++++++++++++ mm/rmap.c | 4 ++-- mm/swap.c | 11 +++-------- mm/vmscan.c | 7 +++---- 4 files changed, 33 insertions(+), 14 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 49c2697046b9..192b593750d3 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -498,6 +498,31 @@ static __always_inline int PageKsm(struct page *page) TESTPAGEFLAG_FALSE(Ksm) #endif +/* + * For pages freed lazily via MADV_FREE. lazyfree pages are clean + * anonymous pages. They have SwapBacked flag cleared to distinguish + * with normal anonymous pages + */ +static __always_inline int __PageLazyFree(struct page *page) +{ + return !PageSwapBacked(page); +} + +static __always_inline int PageLazyFree(struct page *page) +{ + return PageAnon(page) && __PageLazyFree(page); +} + +static __always_inline void SetPageLazyFree(struct page *page) +{ + ClearPageSwapBacked(page); +} + +static __always_inline void ClearPageLazyFree(struct page *page) +{ + SetPageSwapBacked(page); +} + u64 stable_page_flags(struct page *page); static inline int PageUptodate(struct page *page) diff --git a/mm/rmap.c b/mm/rmap.c index 1c02adaa233e..6ec96c8e7826 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1609,7 +1609,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, } /* MADV_FREE page check */ - if (!PageSwapBacked(page)) { + if (__PageLazyFree(page)) { if (!PageDirty(page)) { /* Invalidate as we cleared the pte */ mmu_notifier_invalidate_range(mm, @@ -1623,7 +1623,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma, * discarded. Remap the page to page table. */ set_pte_at(mm, address, pvmw.pte, pteval); - SetPageSwapBacked(page); + ClearPageLazyFree(page); ret = false; page_vma_mapped_walk_done(&pvmw); break; diff --git a/mm/swap.c b/mm/swap.c index c1d3ca80ea10..d83f2cd4cdb8 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -563,7 +563,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec, static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec, void *arg) { - if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) && + if (PageLRU(page) && PageAnon(page) && !__PageLazyFree(page) && !PageSwapCache(page) && !PageUnevictable(page)) { bool active = PageActive(page); @@ -571,12 +571,7 @@ static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec, LRU_INACTIVE_ANON + active); ClearPageActive(page); ClearPageReferenced(page); - /* - * lazyfree pages are clean anonymous pages. They have - * SwapBacked flag cleared to distinguish normal anonymous - * pages - */ - ClearPageSwapBacked(page); + SetPageLazyFree(page); add_page_to_lru_list(page, lruvec, LRU_INACTIVE_FILE); __count_vm_events(PGLAZYFREE, hpage_nr_pages(page)); @@ -678,7 +673,7 @@ void deactivate_page(struct page *page) */ void mark_page_lazyfree(struct page *page) { - if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) && + if (PageLRU(page) && PageAnon(page) && !__PageLazyFree(page) && !PageSwapCache(page) && !PageUnevictable(page)) { struct pagevec *pvec = &get_cpu_var(lru_lazyfree_pvecs); diff --git a/mm/vmscan.c b/mm/vmscan.c index eca49a1c2f68..40bb41ada2d2 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1043,8 +1043,7 @@ static void page_check_dirty_writeback(struct page *page, * Anonymous pages are not handled by flushers and must be written * from reclaim context. Do not stall reclaim based on them */ - if (!page_is_file_cache(page) || - (PageAnon(page) && !PageSwapBacked(page))) { + if (!page_is_file_cache(page) || PageLazyFree(page)) { *dirty = false; *writeback = false; return; @@ -1235,7 +1234,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, * Try to allocate it some swap space here. * Lazyfree page could be freed directly */ - if (PageAnon(page) && PageSwapBacked(page)) { + if (PageAnon(page) && !__PageLazyFree(page)) { if (!PageSwapCache(page)) { if (!(sc->gfp_mask & __GFP_IO)) goto keep_locked; @@ -1411,7 +1410,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, } } - if (PageAnon(page) && !PageSwapBacked(page)) { + if (PageLazyFree(page)) { /* follow __remove_mapping for reference */ if (!page_ref_freeze(page, 1)) goto keep_locked; -- 2.25.0
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