Re: [PATCH 3/3] add isolate pages vmstat

[Minchan Kim <minchan.kim@gmail.com>]

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On Thu, Jul 16, 2009 at 12:16 PM, Andrew
Morton<akpm@linux-foundation.org> wrote:
> On Thu, 16 Jul 2009 09:55:47 +0900 (JST) KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
>
>> ChangeLog
>>   Since v5
>>    - Rewrote the description
>>    - Treat page migration
>>   Since v4
>>    - Changed displaing order in show_free_areas() (as Wu's suggested)
>>   Since v3
>>    - Fixed misaccount page bug when lumby reclaim occur
>>   Since v2
>>    - Separated IsolateLRU field to Isolated(anon) and Isolated(file)
>>   Since v1
>>    - Renamed IsolatePages to IsolatedLRU
>>
>> ==================================
>> Subject: [PATCH] add isolate pages vmstat
>>
>> If the system is running a heavy load of processes then concurrent reclaim
>> can isolate a large numbe of pages from the LRU. /proc/meminfo and the
>> output generated for an OOM do not show how many pages were isolated.
>>
>> This patch shows the information about isolated pages.
>>
>>
>> reproduce way
>> -----------------------
>> % ./hackbench 140 process 1000
>>    => OOM occur
>>
>> active_anon:146 inactive_anon:0 isolated_anon:49245
>>  active_file:79 inactive_file:18 isolated_file:113
>>  unevictable:0 dirty:0 writeback:0 unstable:0 buffer:39
>>  free:370 slab_reclaimable:309 slab_unreclaimable:5492
>>  mapped:53 shmem:15 pagetables:28140 bounce:0
>>
>>
>> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
>> Acked-by: Rik van Riel <riel@redhat.com>
>> Acked-by: Wu Fengguang <fengguang.wu@intel.com>
>> Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
>> ---
>>  drivers/base/node.c    |    4 ++++
>>  fs/proc/meminfo.c      |    4 ++++
>>  include/linux/mmzone.h |    2 ++
>>  mm/migrate.c           |   11 +++++++++++
>>  mm/page_alloc.c        |   12 +++++++++---
>>  mm/vmscan.c            |   12 +++++++++++-
>>  mm/vmstat.c            |    2 ++
>>  7 files changed, 43 insertions(+), 4 deletions(-)
>>
>> Index: b/fs/proc/meminfo.c
>> ===================================================================
>> --- a/fs/proc/meminfo.c
>> +++ b/fs/proc/meminfo.c
>> @@ -65,6 +65,8 @@ static int meminfo_proc_show(struct seq_
>>               "Active(file):   %8lu kB\n"
>>               "Inactive(file): %8lu kB\n"
>>               "Unevictable:    %8lu kB\n"
>> +             "Isolated(anon): %8lu kB\n"
>> +             "Isolated(file): %8lu kB\n"
>>               "Mlocked:        %8lu kB\n"
>
> Are these counters really important enough to justify being present in
> /proc/meminfo?  They seem fairly low-level developer-only details.
> Perhaps relegate them to /proc/vmstat?
>
>>  #ifdef CONFIG_HIGHMEM
>>               "HighTotal:      %8lu kB\n"
>> @@ -110,6 +112,8 @@ static int meminfo_proc_show(struct seq_
>>               K(pages[LRU_ACTIVE_FILE]),
>>               K(pages[LRU_INACTIVE_FILE]),
>>               K(pages[LRU_UNEVICTABLE]),
>> +             K(global_page_state(NR_ISOLATED_ANON)),
>> +             K(global_page_state(NR_ISOLATED_FILE)),
>>               K(global_page_state(NR_MLOCK)),
>>  #ifdef CONFIG_HIGHMEM
>>               K(i.totalhigh),
>> Index: b/include/linux/mmzone.h
>> ===================================================================
>> --- a/include/linux/mmzone.h
>> +++ b/include/linux/mmzone.h
>> @@ -100,6 +100,8 @@ enum zone_stat_item {
>>       NR_BOUNCE,
>>       NR_VMSCAN_WRITE,
>>       NR_WRITEBACK_TEMP,      /* Writeback using temporary buffers */
>> +     NR_ISOLATED_ANON,       /* Temporary isolated pages from anon lru */
>> +     NR_ISOLATED_FILE,       /* Temporary isolated pages from file lru */
>>       NR_SHMEM,               /* shmem pages (included tmpfs/GEM pages) */
>>  #ifdef CONFIG_NUMA
>>       NUMA_HIT,               /* allocated in intended node */
>> Index: b/mm/page_alloc.c
>> ===================================================================
>> --- a/mm/page_alloc.c
>> +++ b/mm/page_alloc.c
>> @@ -2115,16 +2115,18 @@ void show_free_areas(void)
>>               }
>>       }
>>
>> -     printk("Active_anon:%lu active_file:%lu inactive_anon:%lu\n"
>> -             " inactive_file:%lu"
>> +     printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
>> +             " active_file:%lu inactive_file:%lu isolated_file:%lu\n"
>>               " unevictable:%lu"
>>               " dirty:%lu writeback:%lu unstable:%lu buffer:%lu\n"
>>               " free:%lu slab_reclaimable:%lu slab_unreclaimable:%lu\n"
>>               " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n",
>>               global_page_state(NR_ACTIVE_ANON),
>> -             global_page_state(NR_ACTIVE_FILE),
>>               global_page_state(NR_INACTIVE_ANON),
>> +             global_page_state(NR_ISOLATED_ANON),
>> +             global_page_state(NR_ACTIVE_FILE),
>>               global_page_state(NR_INACTIVE_FILE),
>> +             global_page_state(NR_ISOLATED_FILE),
>>               global_page_state(NR_UNEVICTABLE),
>>               global_page_state(NR_FILE_DIRTY),
>>               global_page_state(NR_WRITEBACK),
>> @@ -2152,6 +2154,8 @@ void show_free_areas(void)
>>                       " active_file:%lukB"
>>                       " inactive_file:%lukB"
>>                       " unevictable:%lukB"
>> +                     " isolated(anon):%lukB"
>> +                     " isolated(file):%lukB"
>>                       " present:%lukB"
>>                       " mlocked:%lukB"
>>                       " dirty:%lukB"
>> @@ -2178,6 +2182,8 @@ void show_free_areas(void)
>>                       K(zone_page_state(zone, NR_ACTIVE_FILE)),
>>                       K(zone_page_state(zone, NR_INACTIVE_FILE)),
>>                       K(zone_page_state(zone, NR_UNEVICTABLE)),
>> +                     K(zone_page_state(zone, NR_ISOLATED_ANON)),
>> +                     K(zone_page_state(zone, NR_ISOLATED_FILE)),
>>                       K(zone->present_pages),
>>                       K(zone_page_state(zone, NR_MLOCK)),
>>                       K(zone_page_state(zone, NR_FILE_DIRTY)),
>> Index: b/mm/vmscan.c
>> ===================================================================
>> --- a/mm/vmscan.c
>> +++ b/mm/vmscan.c
>> @@ -1067,6 +1067,8 @@ static unsigned long shrink_inactive_lis
>>               unsigned long nr_active;
>>               unsigned int count[NR_LRU_LISTS] = { 0, };
>>               int mode = lumpy_reclaim ? ISOLATE_BOTH : ISOLATE_INACTIVE;
>> +             unsigned long nr_anon;
>> +             unsigned long nr_file;
>>
>>               nr_taken = sc->isolate_pages(sc->swap_cluster_max,
>>                            &page_list, &nr_scan, sc->order, mode,
>> @@ -1097,6 +1099,10 @@ static unsigned long shrink_inactive_lis
>>               __mod_zone_page_state(zone, NR_INACTIVE_ANON,
>>                                               -count[LRU_INACTIVE_ANON]);
>>
>> +             nr_anon = count[LRU_ACTIVE_ANON] + count[LRU_INACTIVE_ANON];
>> +             nr_file = count[LRU_ACTIVE_FILE] + count[LRU_INACTIVE_FILE];
>> +             __mod_zone_page_state(zone, NR_ISOLATED_ANON, nr_anon);
>> +             __mod_zone_page_state(zone, NR_ISOLATED_FILE, nr_file);
>>
>>               reclaim_stat->recent_scanned[0] += count[LRU_INACTIVE_ANON];
>>               reclaim_stat->recent_scanned[0] += count[LRU_ACTIVE_ANON];
>> @@ -1164,6 +1170,9 @@ static unsigned long shrink_inactive_lis
>>                               spin_lock_irq(&zone->lru_lock);
>>                       }
>>               }
>> +             __mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon);
>> +             __mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file);
>> +
>>       } while (nr_scanned < max_scan);
>
> This is a non-trivial amount of extra stuff.  Do we really need it?
>

I thought so.
This patch results form process fork bomb(ex, mstctl11 in LTP).
Too many isolated patches are based on isolation counter.

So, I think we need this until now.
If we can solve the problem with different method, then we can drop this.

-- 
Kind regards,
Minchan Kim
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