From c841e1d88b8c0a05a34b319838b1a3c0141d68c7 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Wed, 20 Jan 2016 15:03:10 -0800 Subject: [PATCH] mm: free swap cache aggressively if memcg swap is full Swap cache pages are freed aggressively if swap is nearly full (>50% currently), because otherwise we are likely to stop scanning anonymous when we near the swap limit even if there is plenty of freeable swap cache pages. We should follow the same trend in case of memory cgroup, which has its own swap limit. Signed-off-by: Vladimir Davydov Acked-by: Johannes Weiner Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/swap.h | 6 ++++++ mm/memcontrol.c | 22 ++++++++++++++++++++++ mm/memory.c | 3 ++- mm/swapfile.c | 2 +- mm/vmscan.c | 2 +- 5 files changed, 32 insertions(+), 3 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index a587050204f9f..d18b65c53dbb8 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -552,6 +552,7 @@ extern void mem_cgroup_swapout(struct page *page, swp_entry_t entry); extern int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry); extern void mem_cgroup_uncharge_swap(swp_entry_t entry); extern long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg); +extern bool mem_cgroup_swap_full(struct page *page); #else static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) { @@ -571,6 +572,11 @@ static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) { return get_nr_swap_pages(); } + +static inline bool mem_cgroup_swap_full(struct page *page) +{ + return vm_swap_full(); +} #endif #endif /* __KERNEL__*/ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index bcb38718e174f..6a0007965e31e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5761,6 +5761,28 @@ long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) return nr_swap_pages; } +bool mem_cgroup_swap_full(struct page *page) +{ + struct mem_cgroup *memcg; + + VM_BUG_ON_PAGE(!PageLocked(page), page); + + if (vm_swap_full()) + return true; + if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return false; + + memcg = page->mem_cgroup; + if (!memcg) + return false; + + for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) + if (page_counter_read(&memcg->swap) * 2 >= memcg->swap.limit) + return true; + + return false; +} + /* for remember boot option*/ #ifdef CONFIG_MEMCG_SWAP_ENABLED static int really_do_swap_account __initdata = 1; diff --git a/mm/memory.c b/mm/memory.c index ff17850a52d92..30991f83d0bf5 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2582,7 +2582,8 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, } swap_free(entry); - if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) + if (mem_cgroup_swap_full(page) || + (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) try_to_free_swap(page); unlock_page(page); if (page != swapcache) { diff --git a/mm/swapfile.c b/mm/swapfile.c index 22a7a1fc1e478..c43f654a7b645 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1006,7 +1006,7 @@ int free_swap_and_cache(swp_entry_t entry) * Also recheck PageSwapCache now page is locked (above). */ if (PageSwapCache(page) && !PageWriteback(page) && - (!page_mapped(page) || vm_swap_full())) { + (!page_mapped(page) || mem_cgroup_swap_full(page))) { delete_from_swap_cache(page); SetPageDirty(page); } diff --git a/mm/vmscan.c b/mm/vmscan.c index 3be5f9db6c422..bd620b65db526 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1214,7 +1214,7 @@ cull_mlocked: activate_locked: /* Not a candidate for swapping, so reclaim swap space. */ - if (PageSwapCache(page) && vm_swap_full()) + if (PageSwapCache(page) && mem_cgroup_swap_full(page)) try_to_free_swap(page); VM_BUG_ON_PAGE(PageActive(page), page); SetPageActive(page); -- 2.39.5