Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758639Ab1E0BVp (ORCPT ); Thu, 26 May 2011 21:21:45 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:53419 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752515Ab1E0BVo (ORCPT ); Thu, 26 May 2011 21:21:44 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Fri, 27 May 2011 10:14:46 +0900 From: KAMEZAWA Hiroyuki To: Ying Han Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" Subject: Re: [RFC][PATCH v3 10/10] memcg : reclaim statistics Message-Id: <20110527101446.73f2499a.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20110526141047.dc828124.kamezawa.hiroyu@jp.fujitsu.com> <20110526143631.adc2c911.kamezawa.hiroyu@jp.fujitsu.com> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.1.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 13192 Lines: 281 On Thu, 26 May 2011 18:17:04 -0700 Ying Han wrote: > Hi Kame: > > I applied the patch on top of mmotm-2011-05-12-15-52. After boot up, i > keep getting the following crash by reading the > /dev/cgroup/memory/memory.reclaim_stat > > [ 200.776366] Kernel panic - not syncing: Fatal exception > [ 200.781591] Pid: 7535, comm: cat Tainted: G D W 2.6.39-mcg-DEV #130 > [ 200.788463] Call Trace: > [ 200.790916] [] panic+0x91/0x194 > [ 200.797096] [] oops_end+0xae/0xbe > [ 200.803450] [] die+0x5a/0x63 > [ 200.809366] [] do_trap+0x121/0x130 > [ 200.814427] [] do_divide_error+0x90/0x99 > [#1] SMP > [ 200.821395] [] ? mem_cgroup_reclaim_stat_read+0x28/0xf0 > [ 200.829624] [] ? page_add_new_anon_rmap+0x7e/0x90 > [ 200.837372] [] ? handle_pte_fault+0x28a/0x775 > [ 200.844773] [] divide_error+0x15/0x20 > [ 200.851471] [] ? mem_cgroup_reclaim_stat_read+0x28/0xf0 > [ 200.859729] [] cgroup_seqfile_show+0x38/0x46 > [ 200.867036] [] ? cgroup_lock+0x17/0x17 > [ 200.872444] [] seq_read+0x182/0x361 > [ 200.878984] [] vfs_read+0xab/0x107 > [ 200.885403] [] sys_read+0x4a/0x6e > [ 200.891764] [] sysenter_dispatch+0x7/0x27 > > I will debug it, but like to post here in case i missed some patches in between. > It must be mem->scanned is 0 and mem->reclaimed * 100 /mem->scanned cause error. It must be mem->reclaimed * 100 / (mem->scanned +1). I'll fix. thank you for reporting. Thanks, -Kame > --Ying > > On Wed, May 25, 2011 at 10:36 PM, KAMEZAWA Hiroyuki > wrote: > > > > This patch adds a file memory.reclaim_stat. > > > > This file shows following. > > == > > recent_scan_success_ratio  12 # recent reclaim/scan ratio. > > limit_scan_pages 671          # scan caused by hitting limit. > > limit_freed_pages 538         # freed pages by limit_scan > > limit_elapsed_ns 518555076    # elapsed time in LRU scanning by limit. > > soft_scan_pages 0             # scan caused by softlimit. > > soft_freed_pages 0            # freed pages by soft_scan. > > soft_elapsed_ns 0             # elapsed time in LRU scanning by softlimit. > > margin_scan_pages 16744221    # scan caused by auto-keep-margin > > margin_freed_pages 565943     # freed pages by auto-keep-margin. > > margin_elapsed_ns 5545388791  # elapsed time in LRU scanning by auto-keep-margin > > > > This patch adds a new file rather than adding more stats to memory.stat. By it, > > this support "reset" accounting by > > > >  # echo 0 > .../memory.reclaim_stat > > > > This is good for debug and tuning. > > > > TODO: > >  - add Documentaion. > > > > Signed-off-by: KAMEZAWA Hiroyuki > > --- > >  mm/memcontrol.c |   87 ++++++++++++++++++++++++++++++++++++++++++++++++++------ > >  1 file changed, 79 insertions(+), 8 deletions(-) > > > > Index: memcg_async/mm/memcontrol.c > > =================================================================== > > --- memcg_async.orig/mm/memcontrol.c > > +++ memcg_async/mm/memcontrol.c > > @@ -216,6 +216,13 @@ static void mem_cgroup_update_margin_to_ > >  static void mem_cgroup_may_async_reclaim(struct mem_cgroup *mem); > >  static void mem_cgroup_reflesh_scan_ratio(struct mem_cgroup *mem); > > > > +enum scan_type { > > +       LIMIT_SCAN,     /* scan memory because memcg hits limit */ > > +       SOFT_SCAN,      /* scan memory because of soft limit */ > > +       MARGIN_SCAN,    /* scan memory for making margin to limit */ > > +       NR_SCAN_TYPES, > > +}; > > + > >  /* > >  * The memory controller data structure. The memory controller controls both > >  * page cache and RSS per cgroup. We would eventually like to provide > > @@ -300,6 +307,13 @@ struct mem_cgroup { > >        unsigned long   scanned; > >        unsigned long   reclaimed; > >        unsigned long   next_scanratio_update; > > +       /* For statistics */ > > +       struct { > > +               unsigned long nr_scanned_pages; > > +               unsigned long nr_reclaimed_pages; > > +               unsigned long elapsed_ns; > > +       } scan_stat[NR_SCAN_TYPES]; > > + > >        /* > >         * percpu counter. > >         */ > > @@ -1426,7 +1440,9 @@ unsigned int mem_cgroup_swappiness(struc > > > >  static void __mem_cgroup_update_scan_ratio(struct mem_cgroup *mem, > >                                unsigned long scanned, > > -                               unsigned long reclaimed) > > +                               unsigned long reclaimed, > > +                               unsigned long elapsed, > > +                               enum scan_type type) > >  { > >        unsigned long limit; > > > > @@ -1439,6 +1455,9 @@ static void __mem_cgroup_update_scan_rat > >                mem->scanned /= 2; > >                mem->reclaimed /= 2; > >        } > > +       mem->scan_stat[type].nr_scanned_pages += scanned; > > +       mem->scan_stat[type].nr_reclaimed_pages += reclaimed; > > +       mem->scan_stat[type].elapsed_ns += elapsed; > >        spin_unlock(&mem->scan_stat_lock); > >  } > > > > @@ -1448,6 +1467,8 @@ static void __mem_cgroup_update_scan_rat > >  * @root : root memcg of hierarchy walk. > >  * @scanned : scanned pages > >  * @reclaimed: reclaimed pages. > > + * @elapsed: used time for memory reclaim > > + * @type : scan type as LIMIT_SCAN, SOFT_SCAN, MARGIN_SCAN. > >  * > >  * record scan/reclaim ratio to the memcg both to a child and it's root > >  * mem cgroup, which is a reclaim target. This value is used for > > @@ -1457,11 +1478,14 @@ static void __mem_cgroup_update_scan_rat > >  static void mem_cgroup_update_scan_ratio(struct mem_cgroup *mem, > >                                  struct mem_cgroup *root, > >                                unsigned long scanned, > > -                               unsigned long reclaimed) > > +                               unsigned long reclaimed, > > +                               unsigned long elapsed, > > +                               int type) > >  { > > -       __mem_cgroup_update_scan_ratio(mem, scanned, reclaimed); > > +       __mem_cgroup_update_scan_ratio(mem, scanned, reclaimed, elapsed, type); > >        if (mem != root) > > -               __mem_cgroup_update_scan_ratio(root, scanned, reclaimed); > > +               __mem_cgroup_update_scan_ratio(root, scanned, reclaimed, > > +                                       elapsed, type); > > > >  } > > > > @@ -1906,6 +1930,7 @@ static int mem_cgroup_hierarchical_recla > >        bool is_kswapd = false; > >        unsigned long excess; > >        unsigned long nr_scanned; > > +       unsigned long start, end, elapsed; > > > >        excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT; > > > > @@ -1947,18 +1972,24 @@ static int mem_cgroup_hierarchical_recla > >                } > >                /* we use swappiness of local cgroup */ > >                if (check_soft) { > > +                       start = sched_clock(); > >                        ret = mem_cgroup_shrink_node_zone(victim, gfp_mask, > >                                noswap, zone, &nr_scanned); > > +                       end = sched_clock(); > > +                       elapsed = end - start; > >                        *total_scanned += nr_scanned; > >                        mem_cgroup_soft_steal(victim, is_kswapd, ret); > >                        mem_cgroup_soft_scan(victim, is_kswapd, nr_scanned); > >                        mem_cgroup_update_scan_ratio(victim, > > -                                       root_mem, nr_scanned, ret); > > +                               root_mem, nr_scanned, ret, elapsed, SOFT_SCAN); > >                } else { > > +                       start = sched_clock(); > >                        ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, > >                                        noswap, &nr_scanned); > > +                       end = sched_clock(); > > +                       elapsed = end - start; > >                        mem_cgroup_update_scan_ratio(victim, > > -                                       root_mem, nr_scanned, ret); > > +                               root_mem, nr_scanned, ret, elapsed, LIMIT_SCAN); > >                } > >                css_put(&victim->css); > >                /* > > @@ -4003,7 +4034,7 @@ static void mem_cgroup_async_shrink_work > >        struct delayed_work *dw = to_delayed_work(work); > >        struct mem_cgroup *mem, *victim; > >        long nr_to_reclaim; > > -       unsigned long nr_scanned, nr_reclaimed; > > +       unsigned long nr_scanned, nr_reclaimed, start, end; > >        int delay = 0; > > > >        mem = container_of(dw, struct mem_cgroup, async_work); > > @@ -4022,9 +4053,12 @@ static void mem_cgroup_async_shrink_work > >        if (!victim) > >                goto finish_scan; > > > > +       start = sched_clock(); > >        nr_reclaimed = mem_cgroup_shrink_rate_limited(victim, nr_to_reclaim, > >                                        &nr_scanned); > > -       mem_cgroup_update_scan_ratio(victim, mem, nr_scanned, nr_reclaimed); > > +       end = sched_clock(); > > +       mem_cgroup_update_scan_ratio(victim, mem, nr_scanned, nr_reclaimed, > > +                       end - start, MARGIN_SCAN); > >        css_put(&victim->css); > > > >        /* If margin is enough big, stop */ > > @@ -4680,6 +4714,38 @@ static int mem_control_stat_show(struct > >        return 0; > >  } > > > > +static int mem_cgroup_reclaim_stat_read(struct cgroup *cont, struct cftype *cft, > > +                                struct cgroup_map_cb *cb) > > +{ > > +       struct mem_cgroup *mem = mem_cgroup_from_cont(cont); > > +       u64 val; > > +       int i; /* for indexing scan_stat[] */ > > + > > +       val = mem->reclaimed * 100 / mem->scanned; > > +       cb->fill(cb, "recent_scan_success_ratio", val); > > +       i  = LIMIT_SCAN; > > +       cb->fill(cb, "limit_scan_pages", mem->scan_stat[i].nr_scanned_pages); > > +       cb->fill(cb, "limit_freed_pages", mem->scan_stat[i].nr_reclaimed_pages); > > +       cb->fill(cb, "limit_elapsed_ns", mem->scan_stat[i].elapsed_ns); > > +       i = SOFT_SCAN; > > +       cb->fill(cb, "soft_scan_pages", mem->scan_stat[i].nr_scanned_pages); > > +       cb->fill(cb, "soft_freed_pages", mem->scan_stat[i].nr_reclaimed_pages); > > +       cb->fill(cb, "soft_elapsed_ns", mem->scan_stat[i].elapsed_ns); > > +       i = MARGIN_SCAN; > > +       cb->fill(cb, "margin_scan_pages", mem->scan_stat[i].nr_scanned_pages); > > +       cb->fill(cb, "margin_freed_pages", mem->scan_stat[i].nr_reclaimed_pages); > > +       cb->fill(cb, "margin_elapsed_ns", mem->scan_stat[i].elapsed_ns); > > +       return 0; > > +} > > + > > +static int mem_cgroup_reclaim_stat_reset(struct cgroup *cgrp, unsigned int event) > > +{ > > +       struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); > > +       memset(mem->scan_stat, 0, sizeof(mem->scan_stat)); > > +       return 0; > > +} > > + > > + > >  /* > >  * User flags for async_control is a subset of mem->async_flags. But > >  * this needs to be defined independently to hide implemation details. > > @@ -5163,6 +5229,11 @@ static struct cftype mem_cgroup_files[] > >                .open = mem_control_numa_stat_open, > >        }, > >  #endif > > +       { > > +               .name = "reclaim_stat", > > +               .read_map = mem_cgroup_reclaim_stat_read, > > +               .trigger = mem_cgroup_reclaim_stat_reset, > > +       } > >  }; > > > >  #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/