Re: [PATCH v3] mm: memcontrol: add {pgscan,pgsteal}_{kswapd,direct} items in memory.stat of cgroup v2
From: Johannes Weiner
Date: Mon Jun 06 2022 - 13:37:06 EST
On Mon, Jun 06, 2022 at 11:40:28PM +0800, Qi Zheng wrote:
> There are already statistics of {pgscan,pgsteal}_kswapd and
> {pgscan,pgsteal}_direct of memcg event here, but now only the
> sum of the two is displayed in memory.stat of cgroup v2.
>
> In order to obtain more accurate information during monitoring
> and debugging, and to align with the display in /proc/vmstat,
> it better to display {pgscan,pgsteal}_kswapd and
> {pgscan,pgsteal}_direct separately.
>
> Also, for forward compatibility, we still display pgscan and
> pgsteal items so that it won't break existing applications.
>
> Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
> Acked-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> Acked-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
> Acked-by: Michal Hocko <mhocko@xxxxxxxx>
No objection to keeping pgscan and pgsteal, but can you please fix the
doc to present the items in the same order as memory.stat has them?
> @@ -1445,9 +1445,21 @@ PAGE_SIZE multiple when read back.
> pgscan (npn)
> Amount of scanned pages (in an inactive LRU list)
>
> + pgscan_kswapd (npn)
> + Amount of scanned pages by kswapd (in an inactive LRU list)
> +
> + pgscan_direct (npn)
> + Amount of scanned pages directly (in an inactive LRU list)
> +
> pgsteal (npn)
> Amount of reclaimed pages
>
> + pgsteal_kswapd (npn)
> + Amount of reclaimed pages by kswapd
> +
> + pgsteal_direct (npn)
> + Amount of reclaimed pages directly
> +
> pgactivate (npn)
> Amount of pages moved to the active LRU list
vs:
> @@ -1495,41 +1518,17 @@ static char *memory_stat_format(struct mem_cgroup *memcg)
> }
>
> /* Accumulated memory events */
> -
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGFAULT),
> - memcg_events(memcg, PGFAULT));
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGMAJFAULT),
> - memcg_events(memcg, PGMAJFAULT));
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGREFILL),
> - memcg_events(memcg, PGREFILL));
> seq_buf_printf(&s, "pgscan %lu\n",
> memcg_events(memcg, PGSCAN_KSWAPD) +
> memcg_events(memcg, PGSCAN_DIRECT));
> seq_buf_printf(&s, "pgsteal %lu\n",
> memcg_events(memcg, PGSTEAL_KSWAPD) +
> memcg_events(memcg, PGSTEAL_DIRECT));
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGACTIVATE),
> - memcg_events(memcg, PGACTIVATE));
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGDEACTIVATE),
> - memcg_events(memcg, PGDEACTIVATE));
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREE),
> - memcg_events(memcg, PGLAZYFREE));
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREED),
> - memcg_events(memcg, PGLAZYFREED));
> -
> -#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(ZSWPIN),
> - memcg_events(memcg, ZSWPIN));
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(ZSWPOUT),
> - memcg_events(memcg, ZSWPOUT));
> -#endif
>
> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_FAULT_ALLOC),
> - memcg_events(memcg, THP_FAULT_ALLOC));
> - seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_COLLAPSE_ALLOC),
> - memcg_events(memcg, THP_COLLAPSE_ALLOC));
> -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> + for (i = 0; i < ARRAY_SIZE(memcg_vm_event_stat); i++)
> + seq_buf_printf(&s, "%s %lu\n",
> + vm_event_name(memcg_vm_event_stat[i]),
> + memcg_events(memcg, memcg_vm_event_stat[i]));
Thanks