From: Muchun Song <songmuchun@bytedance.com>
To: Shakeel Butt <shakeelb@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Hugh Dickins <hughd@google.com>, Roman Gushchin <guro@fb.com>,
Sami Tolvanen <samitolvanen@google.com>,
Feng Tang <feng.tang@intel.com>, Neil Brown <neilb@suse.de>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Randy Dunlap <rdunlap@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>, Cgroups <cgroups@vger.kernel.org>
Subject: Re: [External] Re: [PATCH v5 2/7] mm: memcontrol: convert NR_ANON_THPS account to pages
Date: Thu, 24 Dec 2020 10:45:58 +0800 [thread overview]
Message-ID: <CAMZfGtVQvD4o-nVdCqNBjWtjDzxcfqme9xMH9ar=C=_sMyDm+g@mail.gmail.com> (raw)
In-Reply-To: <CALvZod7kMhb7k6rDZj18JTE=RMji-SinJmfdcPbN9PUL9Off_w@mail.gmail.com>
On Thu, Dec 24, 2020 at 6:08 AM Shakeel Butt <shakeelb@google.com> wrote:
>
> On Wed, Dec 16, 2020 at 7:45 PM Muchun Song <songmuchun@bytedance.com> wrote:
> >
> > Currently we use struct per_cpu_nodestat to cache the vmstat
> > counters, which leads to inaccurate statistics expecially THP
>
> *especially
Thanks.
>
> > vmstat counters. In the systems with hundreads of processors
>
> *hundreds
Thanks.
>
> > it can be GBs of memory. For example, for a 96 CPUs system,
> > the threshold is the maximum number of 125. And the per cpu
> > counters can cache 23.4375 GB in total.
> >
> > The THP page is already a form of batched addition (it will
> > add 512 worth of memory in one go) so skipping the batching
> > seems like sensible. Although every THP stats update overflows
> > the per-cpu counter, resorting to atomic global updates. But
> > it can make the statistics more accuracy for the THP vmstat
> > counters.
> >
> > So we convert the NR_ANON_THPS account to pages. This patch
> > is consistent with 8f182270dfec ("mm/swap.c: flush lru pvecs
> > on compound page arrival"). Doing this also can make the unit
> > of vmstat counters more unified. Finally, the unit of the vmstat
> > counters are pages, kB and bytes. The B/KB suffix can tell us
> > that the unit is bytes or kB. The rest which is without suffix
> > are pages.
> >
> > Signed-off-by: Muchun Song <songmuchun@bytedance.com>
>
> I agree with the motivation behind this patch but I would like to see
> some performance numbers in the commit message. We might agree to pay
> the price but at least we will know what exactly that cost is.
Do you have any recommendations about benchmarks?
I can do a test. Thanks very much.
--
Yours,
Muchun
next prev parent reply other threads:[~2020-12-24 2:47 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-17 3:43 [PATCH v5 0/7] Convert all THP vmstat counters to pages Muchun Song
2020-12-17 3:43 ` [PATCH v5 1/7] mm: memcontrol: fix NR_ANON_THPS accounting in charge moving Muchun Song
2020-12-23 21:01 ` Shakeel Butt
2020-12-17 3:43 ` [PATCH v5 2/7] mm: memcontrol: convert NR_ANON_THPS account to pages Muchun Song
2020-12-23 22:08 ` Shakeel Butt
2020-12-24 2:45 ` Muchun Song [this message]
2020-12-17 3:43 ` [PATCH v5 3/7] mm: memcontrol: convert NR_FILE_THPS " Muchun Song
2020-12-17 3:43 ` [PATCH v5 4/7] mm: memcontrol: convert NR_SHMEM_THPS " Muchun Song
2020-12-17 3:43 ` [PATCH v5 5/7] mm: memcontrol: convert NR_SHMEM_PMDMAPPED " Muchun Song
2020-12-17 3:43 ` [PATCH v5 6/7] mm: memcontrol: convert NR_FILE_PMDMAPPED " Muchun Song
2020-12-17 3:43 ` [PATCH v5 7/7] mm: memcontrol: make the slab calculation consistent Muchun Song
2020-12-23 21:21 ` Shakeel Butt
2020-12-24 2:43 ` [External] " Muchun Song
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAMZfGtVQvD4o-nVdCqNBjWtjDzxcfqme9xMH9ar=C=_sMyDm+g@mail.gmail.com' \
--to=songmuchun@bytedance.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=cgroups@vger.kernel.org \
--cc=feng.tang@intel.com \
--cc=gregkh@linuxfoundation.org \
--cc=guro@fb.com \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=neilb@suse.de \
--cc=rafael@kernel.org \
--cc=rdunlap@infradead.org \
--cc=samitolvanen@google.com \
--cc=shakeelb@google.com \
--cc=vdavydov.dev@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).