From d8b38438a0bcb362c396f49d8279ef7b505917f4 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Wed, 20 Jan 2016 15:03:07 -0800 Subject: [PATCH] mm: vmscan: do not scan anon pages if memcg swap limit is hit We don't scan anonymous memory if we ran out of swap, neither should we do it in case memcg swap limit is hit, because swap out is impossible anyway. 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 | 13 +++++++++++++ mm/vmscan.c | 2 +- 3 files changed, 20 insertions(+), 1 deletion(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index c2bd163..a587050 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -551,6 +551,7 @@ static inline int mem_cgroup_swappiness(struct mem_cgroup *mem) 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); #else static inline void mem_cgroup_swapout(struct page *page, swp_entry_t entry) { @@ -565,6 +566,11 @@ static inline int mem_cgroup_try_charge_swap(struct page *page, static inline void mem_cgroup_uncharge_swap(swp_entry_t entry) { } + +static inline long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) +{ + return get_nr_swap_pages(); +} #endif #endif /* __KERNEL__*/ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1ff552e..bcb3871 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5748,6 +5748,19 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry) rcu_read_unlock(); } +long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) +{ + long nr_swap_pages = get_nr_swap_pages(); + + if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) + return nr_swap_pages; + for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) + nr_swap_pages = min_t(long, nr_swap_pages, + READ_ONCE(memcg->swap.limit) - + page_counter_read(&memcg->swap)); + return nr_swap_pages; +} + /* for remember boot option*/ #ifdef CONFIG_MEMCG_SWAP_ENABLED static int really_do_swap_account __initdata = 1; diff --git a/mm/vmscan.c b/mm/vmscan.c index 9a8556e..3be5f9d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2004,7 +2004,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg, force_scan = true; /* If we have no swap space, do not bother scanning anon pages. */ - if (!sc->may_swap || (get_nr_swap_pages() <= 0)) { + if (!sc->may_swap || mem_cgroup_get_nr_swap_pages(memcg) <= 0) { scan_balance = SCAN_FILE; goto out; } -- 2.7.4