From e8ea14cc6eadfe2ea63e9989e16e62625a2619f8 Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Wed, 10 Dec 2014 15:42:42 -0800 Subject: mm: memcontrol: take a css reference for each charged page Charges currently pin the css indirectly by playing tricks during css_offline(): user pages stall the offlining process until all of them have been reparented, whereas kmemcg acquires a keep-alive reference if outstanding kernel pages are detected at that point. In preparation for removing all this complexity, make the pinning explicit and acquire a css references for every charged page. Signed-off-by: Johannes Weiner Reviewed-by: Vladimir Davydov Acked-by: Michal Hocko Cc: David Rientjes Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c3cd3bb77dd9..f69da2ac6323 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2273,6 +2273,7 @@ static void drain_stock(struct memcg_stock_pcp *stock) page_counter_uncharge(&old->memory, stock->nr_pages); if (do_swap_account) page_counter_uncharge(&old->memsw, stock->nr_pages); + css_put_many(&old->css, stock->nr_pages); stock->nr_pages = 0; } stock->cached = NULL; @@ -2530,6 +2531,7 @@ bypass: return -EINTR; done_restock: + css_get_many(&memcg->css, batch); if (batch > nr_pages) refill_stock(memcg, batch - nr_pages); done: @@ -2544,6 +2546,8 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) page_counter_uncharge(&memcg->memory, nr_pages); if (do_swap_account) page_counter_uncharge(&memcg->memsw, nr_pages); + + css_put_many(&memcg->css, nr_pages); } /* @@ -2739,6 +2743,7 @@ static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, page_counter_charge(&memcg->memory, nr_pages); if (do_swap_account) page_counter_charge(&memcg->memsw, nr_pages); + css_get_many(&memcg->css, nr_pages); ret = 0; } else if (ret) page_counter_uncharge(&memcg->kmem, nr_pages); @@ -2754,8 +2759,10 @@ static void memcg_uncharge_kmem(struct mem_cgroup *memcg, page_counter_uncharge(&memcg->memsw, nr_pages); /* Not down to 0 */ - if (page_counter_uncharge(&memcg->kmem, nr_pages)) + if (page_counter_uncharge(&memcg->kmem, nr_pages)) { + css_put_many(&memcg->css, nr_pages); return; + } /* * Releases a reference taken in kmem_cgroup_css_offline in case @@ -2767,6 +2774,8 @@ static void memcg_uncharge_kmem(struct mem_cgroup *memcg, */ if (memcg_kmem_test_and_clear_dead(memcg)) css_put(&memcg->css); + + css_put_many(&memcg->css, nr_pages); } /* @@ -3394,10 +3403,13 @@ static int mem_cgroup_move_parent(struct page *page, ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent); if (!ret) { + if (!mem_cgroup_is_root(parent)) + css_get_many(&parent->css, nr_pages); /* Take charge off the local counters */ page_counter_cancel(&child->memory, nr_pages); if (do_swap_account) page_counter_cancel(&child->memsw, nr_pages); + css_put_many(&child->css, nr_pages); } if (nr_pages > 1) @@ -5767,7 +5779,6 @@ static void __mem_cgroup_clear_mc(void) { struct mem_cgroup *from = mc.from; struct mem_cgroup *to = mc.to; - int i; /* we must uncharge all the leftover precharges from mc.to */ if (mc.precharge) { @@ -5795,8 +5806,7 @@ static void __mem_cgroup_clear_mc(void) if (!mem_cgroup_is_root(mc.to)) page_counter_uncharge(&mc.to->memory, mc.moved_swap); - for (i = 0; i < mc.moved_swap; i++) - css_put(&mc.from->css); + css_put_many(&mc.from->css, mc.moved_swap); /* we've already done css_get(mc.to) */ mc.moved_swap = 0; @@ -6343,6 +6353,9 @@ static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout, __this_cpu_add(memcg->stat->nr_page_events, nr_anon + nr_file); memcg_check_events(memcg, dummy_page); local_irq_restore(flags); + + if (!mem_cgroup_is_root(memcg)) + css_put_many(&memcg->css, max(nr_mem, nr_memsw)); } static void uncharge_list(struct list_head *page_list) -- cgit v1.2.3-55-g7522