From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754707Ab1FXVkt (ORCPT ); Fri, 24 Jun 2011 17:40:49 -0400 Received: from smtp-out.google.com ([74.125.121.67]:20848 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753701Ab1FXVks convert rfc822-to-8bit (ORCPT ); Fri, 24 Jun 2011 17:40:48 -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=r/2/5MP7XhETLFE6ydv/JgcLA7tA97zpMFEDh/DStxQjyLOSZyEJxcMEZeZOvLkL43 374mPpAXNiaJ6XsBulBw== MIME-Version: 1.0 In-Reply-To: <20110622092031.e4be1846.kamezawa.hiroyu@jp.fujitsu.com> References: <20110616124730.d6960b8b.kamezawa.hiroyu@jp.fujitsu.com> <20110616125314.4f78b1e0.kamezawa.hiroyu@jp.fujitsu.com> <20110622092031.e4be1846.kamezawa.hiroyu@jp.fujitsu.com> Date: Fri, 24 Jun 2011 14:40:42 -0700 Message-ID: Subject: Re: [PATCH 3/7] memcg: add memory.scan_stat 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" , "bsingharora@gmail.com" , Michal Hocko , "hannes@cmpxchg.org" 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 On Tue, Jun 21, 2011 at 5:20 PM, KAMEZAWA Hiroyuki wrote: > On Mon, 20 Jun 2011 23:49:54 -0700 > Ying Han wrote: > >> On Wed, Jun 15, 2011 at 8:53 PM, KAMEZAWA Hiroyuki < >> kamezawa.hiroyu@jp.fujitsu.com> wrote: >> >> > From e08990dd9ada13cf236bec1ef44b207436434b8e Mon Sep 17 00:00:00 2001 >> > From: KAMEZAWA Hiroyuki >> > Date: Wed, 15 Jun 2011 14:11:01 +0900 >> > Subject: [PATCH 3/7] memcg: add memory.scan_stat >> > >> > commit log of commit 0ae5e89 " memcg: count the soft_limit reclaim in..." >> > says it adds scanning stats to memory.stat file. But it doesn't because >> > we considered we needed to make a concensus for such new APIs. >> > >> > This patch is a trial to add memory.scan_stat. This shows >> >  - the number of scanned pages >> >  - the number of recleimed pages >> >  - the number of elaplsed time (including sleep/pause time) >> >  for both of direct/soft reclaim and shrinking caused by changing limit >> >  or force_empty. >> > >> > The biggest difference with oringinal Ying's one is that this file >> > can be reset by some write, as >> > >> >  # echo 0 ...../memory.scan_stat >> > >> > [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.scan_stat >> > scanned_pages_by_limit 358470 >> > freed_pages_by_limit 180795 >> > elapsed_ns_by_limit 21629927 >> > scanned_pages_by_system 0 >> > freed_pages_by_system 0 >> > elapsed_ns_by_system 0 >> > scanned_pages_by_shrink 76646 >> > freed_pages_by_shrink 38355 >> > elappsed_ns_by_shrink 31990670 >> > >> >> elapsed? >> > > you'r right. > >> >> > total_scanned_pages_by_limit 358470 >> > total_freed_pages_by_limit 180795 >> > total_elapsed_ns_by_hierarchical 216299275 >> > total_scanned_pages_by_system 0 >> > total_freed_pages_by_system 0 >> > total_elapsed_ns_by_system 0 >> > total_scanned_pages_by_shrink 76646 >> > total_freed_pages_by_shrink 38355 >> > total_elapsed_ns_by_shrink 31990670 >> > >> > total_xxxx is for hierarchy management. >> > >> >> For some reason, i feel the opposite where the local stat (like >> "scanned_pages_by_limit") are reclaimed under hierarchical reclaim. The >> total_xxx stats are only incremented for root_mem which is the cgroup >> triggers the hierarchical reclaim. So: >> >> total_scanned_pages_by_limit: number of pages being scanned while the memcg >> hits its limit >> scanned_pages_by_limit: number of pages being scanned while one of the >> memcg's ancestor hits its limit >> >> am i missing something? >> > > scanned_pages_by_limit: one of ancestors and itself's limit. yes, and that is what I understood. > > > > >> >> > >> > This will be useful for further memcg developments and need to be >> > developped before we do some complicated rework on LRU/softlimit >> > management. >> > >> > Now, scan/free/elapsed_by_system is incomplete but future works of >> > Johannes at el. will fill remaining information and then, we can >> > look into problems of isolation between memcgs. >> > >> > Signed-off-by: KAMEZAWA Hiroyuki >> > --- >> >  Documentation/cgroups/memory.txt |   33 +++++++++ >> >  include/linux/memcontrol.h       |   16 ++++ >> >  include/linux/swap.h             |    6 - >> >  mm/memcontrol.c                  |  135 >> > +++++++++++++++++++++++++++++++++++++-- >> >  mm/vmscan.c                      |   27 ++++++- >> >  5 files changed, 199 insertions(+), 18 deletions(-) >> > >> > Index: mmotm-0615/Documentation/cgroups/memory.txt >> > =================================================================== >> > --- mmotm-0615.orig/Documentation/cgroups/memory.txt >> > +++ mmotm-0615/Documentation/cgroups/memory.txt >> > @@ -380,7 +380,7 @@ will be charged as a new owner of it. >> > >> >  5.2 stat file >> > >> > -memory.stat file includes following statistics >> > +5.2.1 memory.stat file includes following statistics >> > >> >  # per-memory cgroup local status >> >  cache          - # of bytes of page cache memory. >> > @@ -438,6 +438,37 @@ Note: >> >         file_mapped is accounted only when the memory cgroup is owner of >> > page >> >         cache.) >> > >> > +5.2.2 memory.scan_stat >> > + >> > +memory.scan_stat includes statistics information for memory scanning and >> > +freeing, reclaiming. The statistics shows memory scanning information >> > since >> > +memory cgroup creation and can be reset to 0 by writing 0 as >> > + >> > + #echo 0 > ../memory.scan_stat >> > + >> > +This file contains following statistics. >> > + >> > +scanned_pages_by_limit - # of scanned pages at hitting limit. >> > +freed_pages_by_limit   - # of freed pages at hitting limit. >> > +elapsed_ns_by_limit    - nano sec of elappsed time at LRU scan at >> > +                                  hitting limit.(this includes sleep >> > time.) >> > >> elapsed? >> >> > + >> > +scanned_pages_by_system        - # of scanned pages by the kernel. >> > +                         (Now, this value means global memory reclaim >> > +                           caused by system memory shortage with a hint >> > +                          of softlimit. "No soft limit" case will be >> > +                          supported in future.) >> > +freed_pages_by_system  - # of freed pages by the kernel. >> > +elapsed_ns_by_system   - nano sec of elappsed time by kernel. >> > + >> > +scanned_pages_by_shrink        - # of scanned pages by shrinking. >> > +                                 (i.e. changes of limit, force_empty, >> > etc.) >> > +freed_pages_by_shrink  - # of freed pages by shirkining. >> > +elappsed_ns_by_shrink  - nano sec of elappsed time at shrinking. >> > >> elapsed? >> >> > + >> > +total_xxx includes the statistics of children scanning caused by the >> > cgroup. >> > >> >> based on the code inspection, the total_xxx also includes the cgroup's scan >> stat as well. >> > > yes. > > >> + >> > + >> >  5.3 swappiness >> > >> >  Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups >> > only. >> > Index: mmotm-0615/include/linux/memcontrol.h >> > =================================================================== >> > --- mmotm-0615.orig/include/linux/memcontrol.h >> > +++ mmotm-0615/include/linux/memcontrol.h >> > @@ -120,6 +120,22 @@ struct zone_reclaim_stat* >> >  mem_cgroup_get_reclaim_stat_from_page(struct page *page); >> >  extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, >> >                                        struct task_struct *p); >> > +struct memcg_scanrecord { >> > +       struct mem_cgroup *mem; /* scanend memory cgroup */ >> > +       struct mem_cgroup *root; /* scan target hierarchy root */ >> > +       int context;            /* scanning context (see memcontrol.c) */ >> > +       unsigned long nr_scanned; /* the number of scanned pages */ >> > +       unsigned long nr_freed; /* the number of freed pages */ >> > +       unsigned long elappsed; /* nsec of time elapsed while scanning */ >> > >> elapsed? >> >> > +}; >> > + >> > +extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, >> > +                                                 gfp_t gfp_mask, bool >> > noswap, >> > +                                                 struct memcg_scanrecord >> > *rec); >> > +extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, >> > +                                               gfp_t gfp_mask, bool >> > noswap, >> > +                                               struct zone *zone, >> > +                                               struct memcg_scanrecord >> > *rec); >> > >> >  #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP >> >  extern int do_swap_account; >> > Index: mmotm-0615/include/linux/swap.h >> > =================================================================== >> > --- mmotm-0615.orig/include/linux/swap.h >> > +++ mmotm-0615/include/linux/swap.h >> > @@ -253,12 +253,6 @@ static inline void lru_cache_add_file(st >> >  /* linux/mm/vmscan.c */ >> >  extern unsigned long try_to_free_pages(struct zonelist *zonelist, int >> > order, >> >                                        gfp_t gfp_mask, nodemask_t *mask); >> > -extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem, >> > -                                                 gfp_t gfp_mask, bool >> > noswap); >> > -extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, >> > -                                               gfp_t gfp_mask, bool >> > noswap, >> > -                                               struct zone *zone, >> > -                                               unsigned long *nr_scanned); >> >  extern int __isolate_lru_page(struct page *page, int mode, int file); >> >  extern unsigned long shrink_all_memory(unsigned long nr_pages); >> >  extern int vm_swappiness; >> > Index: mmotm-0615/mm/memcontrol.c >> > =================================================================== >> > --- mmotm-0615.orig/mm/memcontrol.c >> > +++ mmotm-0615/mm/memcontrol.c >> > @@ -203,6 +203,57 @@ struct mem_cgroup_eventfd_list { >> >  static void mem_cgroup_threshold(struct mem_cgroup *mem); >> >  static void mem_cgroup_oom_notify(struct mem_cgroup *mem); >> > >> > +enum { >> > +       SCAN_BY_LIMIT, >> > +       FREED_BY_LIMIT, >> > +       ELAPSED_BY_LIMIT, >> > + >> > +       SCAN_BY_SYSTEM, >> > +       FREED_BY_SYSTEM, >> > +       ELAPSED_BY_SYSTEM, >> > + >> > +       SCAN_BY_SHRINK, >> > +       FREED_BY_SHRINK, >> > +       ELAPSED_BY_SHRINK, >> > +       NR_SCANSTATS, >> > +}; >> > +#define __FREED                (1) >> > +#define        __ELAPSED       (2) >> > >> >> /tab/space/ >> >> >> > + >> > +struct scanstat { >> > +       spinlock_t      lock; >> > +       unsigned long   stats[NR_SCANSTATS];    /* local statistics */ >> > +       unsigned long   totalstats[NR_SCANSTATS];   /* hierarchical */ >> > +}; I wonder why not extending the mem_cgroup_stat_cpu struct, and then we can use the per-cpu counters like others. diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b7d2d79..5b8bbe9 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -138,6 +138,7 @@ struct mem_cgroup_stat_cpu { long count[MEM_CGROUP_STAT_NSTATS]; unsigned long events[MEM_CGROUP_EVENTS_NSTATS]; unsigned long targets[MEM_CGROUP_NTARGETS]; + unsigned long reclaim_stats[MEMCG_RECLAIM_NSTATS]; }; /* @@ -557,6 +558,101 @@ static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target) this_cpu_write(mem->stat->targets[target], next); } +void mem_cgroup_update_reclaim_stat(struct mem_cgroup *mem, + enum mem_cgroup_reclaim_stat_index idx, + unsigned long num) +{ + this_cpu_add(mem->stat->reclaim_stats[idx], num); +} >> > + >> > +const char *scanstat_string[NR_SCANSTATS] = { >> > +       "scanned_pages_by_limit", >> > +       "freed_pages_by_limit", >> > +       "elapsed_ns_by_limit", >> > + >> > +       "scanned_pages_by_system", >> > +       "freed_pages_by_system", >> > +       "elapsed_ns_by_system", >> > + >> > +       "scanned_pages_by_shrink", >> > +       "freed_pages_by_shrink", >> > +       "elappsed_ns_by_shrink", >> > >> elapsed? >> >> > +}; >> > + >> > +const char *total_scanstat_string[NR_SCANSTATS] = { >> > +       "total_scanned_pages_by_limit", >> > +       "total_freed_pages_by_limit", >> > +       "total_elapsed_ns_by_hierarchical", >> > >> >> typo? >> >> >> > + >> > +       "total_scanned_pages_by_system", >> > +       "total_freed_pages_by_system", >> > +       "total_elapsed_ns_by_system", >> > + >> > +       "total_scanned_pages_by_shrink", >> > +       "total_freed_pages_by_shrink", >> > +       "total_elapsed_ns_by_shrink", >> > +}; >> > + >> >  /* >> >  * The memory controller data structure. The memory controller controls >> > both >> >  * page cache and RSS per cgroup. We would eventually like to provide >> > @@ -264,7 +315,8 @@ struct mem_cgroup { >> > >> >        /* For oom notifier event fd */ >> >        struct list_head oom_notify; >> > - >> > +       /* For recording LRU-scan statistics */ >> > +       struct scanstat scanstat; Can we add this to mem_cgroup_stat_cpu ? >> >        /* >> >         * Should we move charges of a task when a task is moved into this >> >         * mem_cgroup ? And what type of charges should we move ? >> > @@ -1634,6 +1686,28 @@ int mem_cgroup_select_victim_node(struct >> >  } >> >  #endif >> > >> > + >> > + >> > +static void mem_cgroup_record_scanstat(struct memcg_scanrecord *rec) >> > +{ >> > +       struct mem_cgroup *mem; >> > +       int context = rec->context; >> > + >> > +       mem = rec->mem; >> > +       spin_lock(&mem->scanstat.lock); >> > +       mem->scanstat.stats[context] += rec->nr_scanned; >> > +       mem->scanstat.stats[context + __FREED] += rec->nr_freed; >> > +       mem->scanstat.stats[context + __ELAPSED] += rec->elappsed; >> > >> elapsed? >> >> >> +       spin_unlock(&mem->scanstat.lock); >> > + >> > +       mem = rec->root; >> > +       spin_lock(&mem->scanstat.lock); >> > +       mem->scanstat.totalstats[context] += rec->nr_scanned; >> > +       mem->scanstat.totalstats[context + __FREED] += rec->nr_freed; >> > +       mem->scanstat.totalstats[context + __ELAPSED] += rec->elappsed; >> > >> >> elapsed? >> >> > +       spin_unlock(&mem->scanstat.lock); >> > +} >> > + >> >  /* >> >  * Scan the hierarchy if needed to reclaim memory. We remember the last >> > child >> >  * we reclaimed from, so that we don't end up penalizing one child >> > extensively >> > @@ -1659,8 +1733,8 @@ static int mem_cgroup_hierarchical_recla >> >        bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK; >> >        bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT; >> >        unsigned long excess; >> > -       unsigned long nr_scanned; >> >        int visit; >> > +       struct memcg_scanrecord rec; >> > >> >        excess = res_counter_soft_limit_excess(&root_mem->res) >> >> > PAGE_SHIFT; >> > >> > @@ -1668,6 +1742,15 @@ static int mem_cgroup_hierarchical_recla >> >        if (!check_soft && root_mem->memsw_is_minimum) >> >                noswap = true; >> > >> > +       if (shrink) >> > +               rec.context = SCAN_BY_SHRINK; >> > +       else if (check_soft) >> > +               rec.context = SCAN_BY_SYSTEM; >> > +       else >> > +               rec.context = SCAN_BY_LIMIT; >> > + >> > +       rec.root = root_mem; >> > >> >> >> >> > + >> >  again: >> >        if (!shrink) { >> >                visit = 0; >> > @@ -1695,14 +1778,19 @@ again: >> >                        css_put(&victim->css); >> >                        continue; >> >                } >> > +               rec.mem = victim; >> > +               rec.nr_scanned = 0; >> > +               rec.nr_freed = 0; >> > +               rec.elappsed = 0; >> > >> elapsed? >> >> >                /* we use swappiness of local cgroup */ >> >                if (check_soft) { >> >                        ret = mem_cgroup_shrink_node_zone(victim, gfp_mask, >> > -                               noswap, zone, &nr_scanned); >> > -                       *total_scanned += nr_scanned; >> > +                               noswap, zone, &rec); >> > +                       *total_scanned += rec.nr_scanned; >> >                } else >> >                        ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, >> > -                                               noswap); >> > +                                               noswap, &rec); >> > +               mem_cgroup_record_scanstat(&rec); >> >                css_put(&victim->css); >> > >> >                total += ret; >> > @@ -3757,7 +3845,8 @@ try_to_free: >> >                        ret = -EINTR; >> >                        goto out; >> >                } >> > -               progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL, >> > false); >> > +               progress = try_to_free_mem_cgroup_pages(mem, >> > +                               GFP_KERNEL, false, NULL); >> > >> >> So we don't record the stat for force_empty case? >> > > yes, now. force_empty is used only for rmdir(). I don't think log is > necessary for cgroup disappearing. we might need to add that case later, since force_empty can also being used as adding external pressure to the memcg. > > >> >> >                if (!progress) { >> >                        nr_retries--; >> >                        /* maybe some writeback is necessary */ >> > @@ -4599,6 +4688,34 @@ static int mem_control_numa_stat_open(st >> >  } >> >  #endif /* CONFIG_NUMA */ >> > >> > +static int mem_cgroup_scan_stat_read(struct cgroup *cgrp, >> > +                               struct cftype *cft, >> > +                               struct cgroup_map_cb *cb) >> > +{ >> > +       struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); >> > +       int i; >> > + >> > +       for (i = 0; i < NR_SCANSTATS; i++) >> > +               cb->fill(cb, scanstat_string[i], mem->scanstat.stats[i]); >> > +       for (i = 0; i < NR_SCANSTATS; i++) >> > +               cb->fill(cb, total_scanstat_string[i], >> > +                       mem->scanstat.totalstats[i]); >> > +       return 0; >> > +} >> > + >> > +static int mem_cgroup_reset_scan_stat(struct cgroup *cgrp, >> > +                               unsigned int event) >> > +{ >> > +       struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); >> > + >> > +       spin_lock(&mem->scanstat.lock); >> > +       memset(&mem->scanstat.stats, 0, sizeof(mem->scanstat.stats)); >> > +       memset(&mem->scanstat.totalstats, 0, >> > sizeof(mem->scanstat.totalstats)); >> > +       spin_unlock(&mem->scanstat.lock); >> > +       return 0; >> > +} >> > + >> > + >> >  static struct cftype mem_cgroup_files[] = { >> >        { >> >                .name = "usage_in_bytes", >> > @@ -4669,6 +4786,11 @@ static struct cftype mem_cgroup_files[] >> >                .mode = S_IRUGO, >> >        }, >> >  #endif >> > +       { >> > +               .name = "scan_stat", >> > +               .read_map = mem_cgroup_scan_stat_read, >> > +               .trigger = mem_cgroup_reset_scan_stat, >> > +       }, >> >  }; >> > >> >  #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP >> > @@ -4932,6 +5054,7 @@ mem_cgroup_create(struct cgroup_subsys * >> >        atomic_set(&mem->refcnt, 1); >> >        mem->move_charge_at_immigrate = 0; >> >        mutex_init(&mem->thresholds_lock); >> > +       spin_lock_init(&mem->scanstat.lock); >> >        return &mem->css; >> >  free_out: >> >        __mem_cgroup_free(mem); >> > Index: mmotm-0615/mm/vmscan.c >> > =================================================================== >> > --- mmotm-0615.orig/mm/vmscan.c >> > +++ mmotm-0615/mm/vmscan.c >> > @@ -2199,9 +2199,9 @@ unsigned long try_to_free_pages(struct z >> >  #ifdef CONFIG_CGROUP_MEM_RES_CTLR >> > >> >  unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem, >> > -                                               gfp_t gfp_mask, bool >> > noswap, >> > -                                               struct zone *zone, >> > -                                               unsigned long *nr_scanned) >> > +                                       gfp_t gfp_mask, bool noswap, >> > +                                       struct zone *zone, >> > +                                       struct memcg_scanrecord *rec) >> >  { >> >        struct scan_control sc = { >> >                .nr_scanned = 0, >> > @@ -2213,6 +2213,7 @@ unsigned long mem_cgroup_shrink_node_zon >> >                .order = 0, >> >                .mem_cgroup = mem, >> >        }; >> > +       unsigned long start, end; >> > >> >        sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) | >> >                        (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK); >> > @@ -2221,6 +2222,7 @@ unsigned long mem_cgroup_shrink_node_zon >> >                                                      sc.may_writepage, >> >                                                      sc.gfp_mask); >> > >> > +       start = sched_clock(); >> >        /* >> >         * NOTE: Although we can get the priority field, using it >> >         * here is not a good idea, since it limits the pages we can scan. >> > @@ -2229,19 +2231,27 @@ unsigned long mem_cgroup_shrink_node_zon >> >         * the priority and make it zero. >> >         */ >> >        shrink_zone(0, zone, &sc); >> > +       end = sched_clock(); >> > + >> > +       if (rec) { >> > +               rec->nr_scanned += sc.nr_scanned; >> > >> >> >> >> > +               rec->nr_freed += sc.nr_reclaimed; >> > +               rec->elappsed += end - start; >> > >> elapsed? >> >> > +       } >> > >> >        trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed); >> > >> > -       *nr_scanned = sc.nr_scanned; >> >        return sc.nr_reclaimed; >> >  } >> > >> >  unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont, >> >                                           gfp_t gfp_mask, >> > -                                          bool noswap) >> > +                                          bool noswap, >> > +                                          struct memcg_scanrecord *rec) >> >  { >> >        struct zonelist *zonelist; >> >        unsigned long nr_reclaimed; >> > +       unsigned long start, end; >> >        int nid; >> >        struct scan_control sc = { >> >                .may_writepage = !laptop_mode, >> > @@ -2259,6 +2269,7 @@ unsigned long try_to_free_mem_cgroup_pag >> >                .gfp_mask = sc.gfp_mask, >> >        }; >> > >> > +       start = sched_clock(); >> >        /* >> >         * Unlike direct reclaim via alloc_pages(), memcg's reclaim doesn't >> >         * take care of from where we get pages. So the node where we start >> > the >> > @@ -2273,6 +2284,12 @@ unsigned long try_to_free_mem_cgroup_pag >> >                                            sc.gfp_mask); >> > >> >        nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink); >> > +       end = sched_clock(); >> > +       if (rec) { >> > +               rec->nr_scanned += sc.nr_scanned; >> > >> >> sc.nr_scanned only contains the nr_scanned of last >> priority do_try_to_free_pages(). we need to reset it to total_scanned before >> return. I am looking at v3.0-rc3 . >> > > Hm. ok, then, total_reclaimed in softlimit is buggy, too. > I'll check. Thanks --Ying > > Thanks, > -Kame > >