From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758635Ab1E0BRK (ORCPT ); Thu, 26 May 2011 21:17:10 -0400 Received: from smtp-out.google.com ([74.125.121.67]:4021 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752380Ab1E0BRI convert rfc822-to-8bit (ORCPT ); Thu, 26 May 2011 21:17:08 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=Tjy+eUmJVlyfXpR+l55OBs/UW72j5yqPhcCgayMR60ak44RMZJ4TtRLd/OuO930zG4 JmvhRY5Sq88Y6RK58aLQ== MIME-Version: 1.0 In-Reply-To: <20110526143631.adc2c911.kamezawa.hiroyu@jp.fujitsu.com> References: <20110526141047.dc828124.kamezawa.hiroyu@jp.fujitsu.com> <20110526143631.adc2c911.kamezawa.hiroyu@jp.fujitsu.com> Date: Thu, 26 May 2011 18:17:04 -0700 Message-ID: Subject: Re: [RFC][PATCH v3 10/10] memcg : reclaim statistics From: Ying Han To: KAMEZAWA Hiroyuki 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" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. --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 >