From 6abb5a867ba0866cb21827b172cee6aa71244bd1 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Fri, 8 Aug 2014 14:19:33 -0700 Subject: mm: memcontrol: avoid charge statistics churn during page migration Charge migration currently disables IRQs twice to update the charge statistics for the old page and then again for the new page. But migration is a seamless transition of a charge from one physical page to another one of the same size, so this should be a non-event from an accounting point of view. Leave the statistics alone. Signed-off-by: Johannes Weiner Acked-by: Michal Hocko Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 35 ++++++++++------------------------- 1 file changed, 10 insertions(+), 25 deletions(-) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a6e2be0241af..ec4dcf1b9562 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2728,7 +2728,7 @@ static void unlock_page_lru(struct page *page, int isolated) } static void commit_charge(struct page *page, struct mem_cgroup *memcg, - unsigned int nr_pages, bool lrucare) + bool lrucare) { struct page_cgroup *pc = lookup_page_cgroup(page); int isolated; @@ -2765,16 +2765,6 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg, if (lrucare) unlock_page_lru(page, isolated); - - local_irq_disable(); - mem_cgroup_charge_statistics(memcg, page, nr_pages); - /* - * "charge_statistics" updated event counter. Then, check it. - * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. - * if they exceeds softlimit. - */ - memcg_check_events(memcg, page); - local_irq_enable(); } static DEFINE_MUTEX(set_limit_mutex); @@ -6460,12 +6450,17 @@ void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg, if (!memcg) return; + commit_charge(page, memcg, lrucare); + if (PageTransHuge(page)) { nr_pages <<= compound_order(page); VM_BUG_ON_PAGE(!PageTransHuge(page), page); } - commit_charge(page, memcg, nr_pages, lrucare); + local_irq_disable(); + mem_cgroup_charge_statistics(memcg, page, nr_pages); + memcg_check_events(memcg, page); + local_irq_enable(); if (do_swap_account && PageSwapCache(page)) { swp_entry_t entry = { .val = page_private(page) }; @@ -6651,7 +6646,6 @@ void mem_cgroup_uncharge_list(struct list_head *page_list) void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, bool lrucare) { - unsigned int nr_pages = 1; struct page_cgroup *pc; int isolated; @@ -6660,6 +6654,8 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, VM_BUG_ON_PAGE(!lrucare && PageLRU(oldpage), oldpage); VM_BUG_ON_PAGE(!lrucare && PageLRU(newpage), newpage); VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage); + VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage), + newpage); if (mem_cgroup_disabled()) return; @@ -6677,12 +6673,6 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage); VM_BUG_ON_PAGE(do_swap_account && !(pc->flags & PCG_MEMSW), oldpage); - if (PageTransHuge(oldpage)) { - nr_pages <<= compound_order(oldpage); - VM_BUG_ON_PAGE(!PageTransHuge(oldpage), oldpage); - VM_BUG_ON_PAGE(!PageTransHuge(newpage), newpage); - } - if (lrucare) lock_page_lru(oldpage, &isolated); @@ -6691,12 +6681,7 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, if (lrucare) unlock_page_lru(oldpage, isolated); - local_irq_disable(); - mem_cgroup_charge_statistics(pc->mem_cgroup, oldpage, -nr_pages); - memcg_check_events(pc->mem_cgroup, oldpage); - local_irq_enable(); - - commit_charge(newpage, pc->mem_cgroup, nr_pages, lrucare); + commit_charge(newpage, pc->mem_cgroup, lrucare); } /* -- cgit v1.2.3