Re: [PATCH v3] mm: memcontrol: add {pgscan,pgsteal}_{kswapd,direct} items in memory.stat of cgroup v2

[Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>]

On 2022/6/7 1:34 AM, Johannes Weiner wrote:
> 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?

Sure, will fix.

Thanks,
Qi

> > @@ -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

--
Thanks,
Qi