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

[Andrew Morton <akpm@linux-foundation.org>]

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?