From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 23D666B004F for ; Tue, 11 Aug 2009 10:44:14 -0400 (EDT) Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by e28smtp06.in.ibm.com (8.14.3/8.13.1) with ESMTP id n7BEiANL024585 for ; Tue, 11 Aug 2009 20:14:10 +0530 Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id n7BEi9BI2019516 for ; Tue, 11 Aug 2009 20:14:10 +0530 Received: from d28av05.in.ibm.com (loopback [127.0.0.1]) by d28av05.in.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id n7BEi87t022815 for ; Wed, 12 Aug 2009 00:44:09 +1000 Date: Tue, 11 Aug 2009 20:14:05 +0530 From: Balbir Singh Subject: Help Resource Counters Scale better (v4) Message-ID: <20090811144405.GW7176@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Sender: owner-linux-mm@kvack.org To: Andrew Morton , KAMEZAWA Hiroyuki , "nishimura@mxp.nes.nec.co.jp" , KOSAKI Motohiro , "menage@google.com" , Prarit Bhargava , andi.kleen@intel.com, Pavel Emelianov , "lizf@cn.fujitsu.com" Cc: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" List-ID: Enhancement: Remove the overhead of root based resource counter accounting From: Balbir Singh This patch reduces the resource counter overhead (mostly spinlock) associated with the root cgroup. This is a part of the several patches to reduce mem cgroup overhead. I had posted other approaches earlier (including using percpu counters). Those patches will be a natural addition and will be added iteratively on top of these. The patch stops resource counter accounting for the root cgroup. The data for display is derived from the statisitcs we maintain via mem_cgroup_charge_statistics (which is more scalable). The tests results I see on a 24 way show that 1. The lock contention disappears from /proc/lock_stats 2. The results of the test are comparable to running with cgroup_disable=memory. Please test/review. --- mm/memcontrol.c | 89 +++++++++++++++++++++++++++++++++++++++++++------------ 1 files changed, 70 insertions(+), 19 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 48a38e1..6d82f8d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -70,6 +70,7 @@ enum mem_cgroup_stat_index { MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */ MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */ MEM_CGROUP_STAT_EVENTS, /* sum of pagein + pageout for internal use */ + MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ MEM_CGROUP_STAT_NSTATS, }; @@ -478,6 +479,19 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) return mz; } +static void mem_cgroup_swap_statistics(struct mem_cgroup *mem, + bool charge) +{ + int val = (charge)? 1 : -1; + struct mem_cgroup_stat *stat = &mem->stat; + struct mem_cgroup_stat_cpu *cpustat; + int cpu = get_cpu(); + + cpustat = &stat->cpustat[cpu]; + __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_SWAPOUT, val); + put_cpu(); +} + static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, struct page_cgroup *pc, bool charge) @@ -1281,9 +1295,11 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, VM_BUG_ON(css_is_removed(&mem->css)); while (1) { - int ret; + int ret = 0; unsigned long flags = 0; + if (mem_cgroup_is_root(mem)) + goto done; ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res, &soft_fail_res); if (likely(!ret)) { @@ -1343,6 +1359,7 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm, if (mem_cgroup_soft_limit_check(mem_over_soft_limit)) mem_cgroup_update_tree(mem_over_soft_limit, page); } +done: return 0; nomem: css_put(&mem->css); @@ -1415,9 +1432,12 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem, lock_page_cgroup(pc); if (unlikely(PageCgroupUsed(pc))) { unlock_page_cgroup(pc); - res_counter_uncharge(&mem->res, PAGE_SIZE, NULL); - if (do_swap_account) - res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL); + if (!mem_cgroup_is_root(mem)) { + res_counter_uncharge(&mem->res, PAGE_SIZE, NULL); + if (do_swap_account) + res_counter_uncharge(&mem->memsw, PAGE_SIZE, + NULL); + } css_put(&mem->css); return; } @@ -1494,7 +1514,8 @@ static int mem_cgroup_move_account(struct page_cgroup *pc, if (pc->mem_cgroup != from) goto out; - res_counter_uncharge(&from->res, PAGE_SIZE, NULL); + if (!mem_cgroup_is_root(from)) + res_counter_uncharge(&from->res, PAGE_SIZE, NULL); mem_cgroup_charge_statistics(from, pc, false); page = pc->page; @@ -1513,7 +1534,7 @@ static int mem_cgroup_move_account(struct page_cgroup *pc, 1); } - if (do_swap_account) + if (do_swap_account && !mem_cgroup_is_root(from)) res_counter_uncharge(&from->memsw, PAGE_SIZE, NULL); css_put(&from->css); @@ -1584,9 +1605,11 @@ uncharge: /* drop extra refcnt by try_charge() */ css_put(&parent->css); /* uncharge if move fails */ - res_counter_uncharge(&parent->res, PAGE_SIZE, NULL); - if (do_swap_account) - res_counter_uncharge(&parent->memsw, PAGE_SIZE, NULL); + if (!mem_cgroup_is_root(parent)) { + res_counter_uncharge(&parent->res, PAGE_SIZE, NULL); + if (do_swap_account) + res_counter_uncharge(&parent->memsw, PAGE_SIZE, NULL); + } return ret; } @@ -1775,7 +1798,10 @@ __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, * This recorded memcg can be obsolete one. So, avoid * calling css_tryget */ - res_counter_uncharge(&memcg->memsw, PAGE_SIZE, NULL); + if (!mem_cgroup_is_root(memcg)) + res_counter_uncharge(&memcg->memsw, PAGE_SIZE, + NULL); + mem_cgroup_swap_statistics(memcg, false); mem_cgroup_put(memcg); } rcu_read_unlock(); @@ -1800,9 +1826,11 @@ void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem) return; if (!mem) return; - res_counter_uncharge(&mem->res, PAGE_SIZE, NULL); - if (do_swap_account) - res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL); + if (!mem_cgroup_is_root(mem)) { + res_counter_uncharge(&mem->res, PAGE_SIZE, NULL); + if (do_swap_account) + res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL); + } css_put(&mem->css); } @@ -1855,9 +1883,14 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) break; } - res_counter_uncharge(&mem->res, PAGE_SIZE, &soft_limit_excess); - if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)) - res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL); + if (!mem_cgroup_is_root(mem)) { + res_counter_uncharge(&mem->res, PAGE_SIZE, &soft_limit_excess); + if (do_swap_account && + (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)) + res_counter_uncharge(&mem->memsw, PAGE_SIZE, NULL); + } + if (ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT && mem_cgroup_is_root(mem)) + mem_cgroup_swap_statistics(mem, true); mem_cgroup_charge_statistics(mem, pc, false); ClearPageCgroupUsed(pc); @@ -1948,7 +1981,9 @@ void mem_cgroup_uncharge_swap(swp_entry_t ent) * We uncharge this because swap is freed. * This memcg can be obsolete one. We avoid calling css_tryget */ - res_counter_uncharge(&memcg->memsw, PAGE_SIZE, NULL); + if (!mem_cgroup_is_root(memcg)) + res_counter_uncharge(&memcg->memsw, PAGE_SIZE, NULL); + mem_cgroup_swap_statistics(memcg, false); mem_cgroup_put(memcg); } rcu_read_unlock(); @@ -2461,10 +2496,26 @@ static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) name = MEMFILE_ATTR(cft->private); switch (type) { case _MEM: - val = res_counter_read_u64(&mem->res, name); + if (name == RES_USAGE && mem_cgroup_is_root(mem)) { + val = mem_cgroup_read_stat(&mem->stat, + MEM_CGROUP_STAT_CACHE); + val += mem_cgroup_read_stat(&mem->stat, + MEM_CGROUP_STAT_RSS); + val <<= PAGE_SHIFT; + } else + val = res_counter_read_u64(&mem->res, name); break; case _MEMSWAP: - val = res_counter_read_u64(&mem->memsw, name); + if (name == RES_USAGE && mem_cgroup_is_root(mem)) { + val = mem_cgroup_read_stat(&mem->stat, + MEM_CGROUP_STAT_CACHE); + val += mem_cgroup_read_stat(&mem->stat, + MEM_CGROUP_STAT_RSS); + val += mem_cgroup_read_stat(&mem->stat, + MEM_CGROUP_STAT_SWAPOUT); + val <<= PAGE_SHIFT; + } else + val = res_counter_read_u64(&mem->memsw, name); break; default: BUG(); -- Balbir -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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