On Wed, Apr 27, 2011 at 8:16 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> sorry, I had wrong TO:...
>
> Begin forwarded message:
>
> Date: Thu, 28 Apr 2011 12:02:34 +0900
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> To: linux-mm@xxxxxxxxxxxxxxx
> Cc: "linux-kernel@xxxxxxxxxxxxxxx" <linux-kernel@xxxxxxxxxxxxxxx>, "nishimura@xxxxxxxxxxxxxxxxx" <nishimura@xxxxxxxxxxxxxxxxx>, "balbir@xxxxxxxxxxxxxxxxxx" <balbir@xxxxxxxxxxxxxxxxxx>, Ying Han <yinghan@xxxxxxxxxx>, "akpm@xxxxxxxxxxxxxxxxxxxx" <akpm@xxxxxxxxxxxxxxxxxxxx>
> Subject: [PATCH] memcg: add reclaim statistics accounting
>
>
>
> Now, memory cgroup provides poor reclaim statistics per memcg. This
> patch adds statistics for direct/soft reclaim as the number of
> pages scans, the number of page freed by reclaim, the nanoseconds of
> latency at reclaim.
>
> It's good to add statistics before we modify memcg/global reclaim, largely.
> This patch refactors current soft limit status and add an unified update logic.
>
> For example, After #cat 195Mfile > /dev/null under 100M limit.
> # cat /cgroup/memory/A/memory.stat
> ....
> limit_freed 24592
why not "limit_steal" ?
> soft_steal 0
> limit_scan 43974
> soft_scan 0
> limit_latency 133837417
>
> nearly 96M caches are freed. scanned twice. used 133ms.
Does it make sense to split up the soft_steal/scan for bg reclaim and
direct reclaim? The same for the limit_steal/scan. I am now testing
the patch to add the soft_limit reclaim on global ttfp, and i already
have the patch to add the following:
kswapd_soft_steal 0
kswapd_soft_scan 0
direct_soft_steal 0
direct_soft_scan 0
kswapd_steal 0
pg_pgsteal 0
kswapd_pgscan 0
pg_scan 0
It is more clear to me to have finer granularity of the stats. Let me
know if that works or not. I probably can post it this week.
--Ying
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamaezawa.hiroyu@xxxxxxxxxxxxxx>
> ---
> Documentation/cgroups/memory.txt | 13 ++++++--
> include/linux/memcontrol.h | 1
> include/linux/swap.h | 10 ++----
> mm/memcontrol.c | 63 ++++++++++++++++++++++++---------------
> mm/vmscan.c | 25 +++++++++++++--
> 5 files changed, 77 insertions(+), 35 deletions(-)
>
> Index: memcg/include/linux/memcontrol.h
> ===================================================================
> --- memcg.orig/include/linux/memcontrol.h
> +++ memcg/include/linux/memcontrol.h
> @@ -106,6 +106,7 @@ extern void mem_cgroup_end_migration(str
> /*
> * For memory reclaim.
> */
> +enum { RECLAIM_SCAN, RECLAIM_FREE, RECLAIM_LATENCY, NR_RECLAIM_INFO};
> int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg);
> int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg);
> int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
> Index: memcg/mm/memcontrol.c
> ===================================================================
> --- memcg.orig/mm/memcontrol.c
> +++ memcg/mm/memcontrol.c
> @@ -96,10 +96,6 @@ enum mem_cgroup_events_index {
> MEM_CGROUP_EVENTS_COUNT, /* # of pages paged in/out */
> MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */
> MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */
> - MEM_CGROUP_EVENTS_SOFT_STEAL, /* # of pages reclaimed from */
> - /* soft reclaim */
> - MEM_CGROUP_EVENTS_SOFT_SCAN, /* # of pages scanned from */
> - /* soft reclaim */
> MEM_CGROUP_EVENTS_NSTATS,
> };
> /*
> @@ -206,6 +202,9 @@ struct mem_cgroup_eventfd_list {
> static void mem_cgroup_threshold(struct mem_cgroup *mem);
> static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
>
> +/* memory reclaim contexts */
> +enum { MEM_LIMIT, MEM_SOFT, NR_MEM_CONTEXTS};
> +
> /*
> * The memory controller data structure. The memory controller controls both
> * page cache and RSS per cgroup. We would eventually like to provide
> @@ -242,6 +241,7 @@ struct mem_cgroup {
> nodemask_t scan_nodes;
> unsigned long next_scan_node_update;
> #endif
> + atomic_long_t reclaim_info[NR_MEM_CONTEXTS][NR_RECLAIM_INFO];
> /*
> * Should the accounting and control be hierarchical, per subtree?
> */
> @@ -645,16 +645,6 @@ static void mem_cgroup_charge_statistics
> preempt_enable();
> }
>
> -static void mem_cgroup_soft_steal(struct mem_cgroup *mem, int val)
> -{
> - this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_SOFT_STEAL], val);
> -}
> -
> -static void mem_cgroup_soft_scan(struct mem_cgroup *mem, int val)
> -{
> - this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_SOFT_SCAN], val);
> -}
> -
> static unsigned long
> mem_cgroup_get_zonestat_node(struct mem_cgroup *mem, int nid, enum lru_list idx)
> {
> @@ -679,6 +669,15 @@ static unsigned long mem_cgroup_get_loca
> return total;
> }
>
> +void mem_cgroup_update_reclaim_info(struct mem_cgroup *mem, int context,
> + unsigned long *stats)
> +{
> + int i;
> + for (i = 0; i < NR_RECLAIM_INFO; i++)
> + atomic_long_add(stats[i], &mem->reclaim_info[context][i]);
> +}
> +
> +
> static bool __memcg_event_check(struct mem_cgroup *mem, int target)
> {
> unsigned long val, next;
> @@ -1560,6 +1559,8 @@ int mem_cgroup_select_victim_node(struct
> }
> #endif
>
> +
> +
> /*
> * 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
> @@ -1585,7 +1586,8 @@ 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;
> + unsigned long stats[NR_RECLAIM_INFO];
> + int context = (check_soft)? MEM_SOFT : MEM_LIMIT;
>
> excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
>
> @@ -1631,13 +1633,12 @@ static int mem_cgroup_hierarchical_recla
> if (check_soft) {
> ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
> noswap, get_swappiness(victim), zone,
> - &nr_scanned);
> - *total_scanned += nr_scanned;
> - mem_cgroup_soft_steal(victim, ret);
> - mem_cgroup_soft_scan(victim, nr_scanned);
> + stats);
> + *total_scanned += stats[RECLAIM_SCAN];
> } else
> ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
> - noswap, get_swappiness(victim));
> + noswap, get_swappiness(victim),stats);
> + mem_cgroup_update_reclaim_info(victim, context, stats);
> css_put(&victim->css);
> /*
> * At shrinking usage, we can't check we should stop here or
> @@ -3661,7 +3662,7 @@ try_to_free:
> goto out;
> }
> progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
> - false, get_swappiness(mem));
> + false, get_swappiness(mem), NULL);
> if (!progress) {
> nr_retries--;
> /* maybe some writeback is necessary */
> @@ -3929,8 +3930,12 @@ enum {
> MCS_SWAP,
> MCS_PGFAULT,
> MCS_PGMAJFAULT,
> + MCS_LIMIT_FREED,
> MCS_SOFT_STEAL,
> + MCS_LIMIT_SCAN,
> MCS_SOFT_SCAN,
> + MCS_LIMIT_LATENCY,
> + MCS_SOFT_LATENCY,
> MCS_INACTIVE_ANON,
> MCS_ACTIVE_ANON,
> MCS_INACTIVE_FILE,
> @@ -3955,8 +3960,12 @@ struct {
> {"swap", "total_swap"},
> {"pgfault", "total_pgfault"},
> {"pgmajfault", "total_pgmajfault"},
> + {"limit_freed", "total_limit_freed"},
> {"soft_steal", "total_soft_steal"},
> + {"limit_scan", "total_limit_scan"},
> {"soft_scan", "total_soft_scan"},
> + {"limit_latency", "total_limit_latency"},
> + {"soft_latency", "total_soft_latency"},
> {"inactive_anon", "total_inactive_anon"},
> {"active_anon", "total_active_anon"},
> {"inactive_file", "total_inactive_file"},
> @@ -3985,10 +3994,18 @@ mem_cgroup_get_local_stat(struct mem_cgr
> val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
> s->stat[MCS_SWAP] += val * PAGE_SIZE;
> }
> - val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_SOFT_STEAL);
> + val = atomic_long_read(&mem->reclaim_info[MEM_LIMIT][RECLAIM_FREE]);
> + s->stat[MCS_LIMIT_FREED] += val;
> + val = atomic_long_read(&mem->reclaim_info[MEM_SOFT][RECLAIM_FREE]);
> s->stat[MCS_SOFT_STEAL] += val;
> - val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_SOFT_SCAN);
> + val = atomic_long_read(&mem->reclaim_info[MEM_LIMIT][RECLAIM_SCAN]);
> + s->stat[MCS_LIMIT_SCAN] += val;
> + val = atomic_long_read(&mem->reclaim_info[MEM_SOFT][RECLAIM_SCAN]);
> s->stat[MCS_SOFT_SCAN] += val;
> + val = atomic_long_read(&mem->reclaim_info[MEM_LIMIT][RECLAIM_LATENCY]);
> + s->stat[MCS_LIMIT_LATENCY] += val;
> + val = atomic_long_read(&mem->reclaim_info[MEM_SOFT][RECLAIM_LATENCY]);
> + s->stat[MCS_SOFT_LATENCY] += val;
> val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGFAULT);
> s->stat[MCS_PGFAULT] += val;
> val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGMAJFAULT);
> Index: memcg/mm/vmscan.c
> ===================================================================
> --- memcg.orig/mm/vmscan.c
> +++ memcg/mm/vmscan.c
> @@ -2156,7 +2156,7 @@ unsigned long mem_cgroup_shrink_node_zon
> gfp_t gfp_mask, bool noswap,
> unsigned int swappiness,
> struct zone *zone,
> - unsigned long *nr_scanned)
> + unsigned long *stats)
> {
> struct scan_control sc = {
> .nr_scanned = 0,
> @@ -2168,6 +2168,9 @@ unsigned long mem_cgroup_shrink_node_zon
> .order = 0,
> .mem_cgroup = mem,
> };
> + u64 start, end;
> +
> + start = sched_clock();
>
> sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
> (GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
> @@ -2175,7 +2178,6 @@ unsigned long mem_cgroup_shrink_node_zon
> trace_mm_vmscan_memcg_softlimit_reclaim_begin(0,
> sc.may_writepage,
> sc.gfp_mask);
> -
> /*
> * NOTE: Although we can get the priority field, using it
> * here is not a good idea, since it limits the pages we can scan.
> @@ -2185,20 +2187,26 @@ unsigned long mem_cgroup_shrink_node_zon
> */
> shrink_zone(0, zone, &sc);
>
> + stats[RECLAIM_SCAN] = sc.nr_scanned;
> + stats[RECLAIM_FREE] = sc.nr_reclaimed;
> + end = sched_clock();
> + stats[RECLAIM_LATENCY] = end - start;
> +
> 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,
> - unsigned int swappiness)
> + unsigned int swappiness,
> + unsigned long *stats)
> {
> struct zonelist *zonelist;
> unsigned long nr_reclaimed;
> int nid;
> + u64 end, start;
> struct scan_control sc = {
> .may_writepage = !laptop_mode,
> .may_unmap = 1,
> @@ -2209,6 +2217,8 @@ unsigned long try_to_free_mem_cgroup_pag
> .mem_cgroup = mem_cont,
> .nodemask = NULL, /* we don't care the placement */
> };
> +
> + start = sched_clock();
> /*
> * Unlike direct reclaim via alloc_pages(), memcg's reclaim
> * don't take care of from where we get pages . So, the node where
> @@ -2226,6 +2236,13 @@ unsigned long try_to_free_mem_cgroup_pag
>
> nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
>
> + if (stats) {
> + stats[RECLAIM_SCAN] = sc.nr_scanned;
> + stats[RECLAIM_FREE] = sc.nr_reclaimed;
> + end = sched_clock();
> + stats[RECLAIM_LATENCY] = end - start;
> + }
> +
> trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed);
>
> return nr_reclaimed;
> Index: memcg/Documentation/cgroups/memory.txt
> ===================================================================
> --- memcg.orig/Documentation/cgroups/memory.txt
> +++ memcg/Documentation/cgroups/memory.txt
> @@ -387,8 +387,13 @@ pgpgout - # of pages paged out (equival
> swap - # of bytes of swap usage
> pgfault - # of page faults.
> pgmajfault - # of major page faults.
> -soft_steal - # of pages reclaimed from global hierarchical reclaim
> -soft_scan - # of pages scanned from global hierarchical reclaim
> +limit_freed - # of pages reclaimed by hitting limit.
> +soft_steal - # of pages reclaimed by kernel with hints of soft limit
> +limit_scan - # of pages scanned by hitting limit.
> +soft_scan - # of pages scanned by kernel with hints of soft limit
> +limit_latency - # of nanosecs epalsed at reclaiming by hitting limit
> +soft_latency - # of nanosecs epalsed at reclaiming by kernel with hits of
> + soft limit.
> inactive_anon - # of bytes of anonymous memory and swap cache memory on
> LRU list.
> active_anon - # of bytes of anonymous and swap cache memory on active
> @@ -412,8 +417,12 @@ total_pgpgout - sum of all children's "
> total_swap - sum of all children's "swap"
> total_pgfault - sum of all children's "pgfault"
> total_pgmajfault - sum of all children's "pgmajfault"
> +total_limit_freed - sum of all children's "limit_freed"
> total_soft_steal - sum of all children's "soft_steal"
> +total_limit_scan - sum of all children's "limit_scan"
> total_soft_scan - sum of all children's "soft_scan"
> +total_limit_latency - sum of all children's "limit_latency"
> +total_soft_latency - sum of all children's "soft_latency"
> total_inactive_anon - sum of all children's "inactive_anon"
> total_active_anon - sum of all children's "active_anon"
> total_inactive_file - sum of all children's "inactive_file"
> Index: memcg/include/linux/swap.h
> ===================================================================
> --- memcg.orig/include/linux/swap.h
> +++ memcg/include/linux/swap.h
> @@ -252,13 +252,11 @@ static inline void lru_cache_add_file(st
> 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,
> - unsigned int swappiness);
> + gfp_t gfp_mask, bool noswap, unsigned int swappiness,
> + unsigned long *stats);
> extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
> - gfp_t gfp_mask, bool noswap,
> - unsigned int swappiness,
> - struct zone *zone,
> - unsigned long *nr_scanned);
> + gfp_t gfp_mask, bool noswap, unsigned int swappiness,
> + struct zone *zone, unsigned long *stats);
> 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;
>
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