From: Michal Hocko <mhocko@suse.cz>
To: Dave Hansen <dave@sr71.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Hugh Dickins <hughd@google.com>,
Dave Hansen <dave.hansen@intel.com>, Tejun Heo <tj@kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Vladimir Davydov <vdavydov@parallels.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: regression caused by cgroups optimization in 3.17-rc2
Date: Fri, 5 Sep 2014 11:25:37 +0200 [thread overview]
Message-ID: <20140905092537.GC26243@dhcp22.suse.cz> (raw)
In-Reply-To: <5408CB2E.3080101@sr71.net>
On Thu 04-09-14 13:27:26, Dave Hansen wrote:
> On 09/04/2014 07:27 AM, Michal Hocko wrote:
> > Ouch. free_pages_and_swap_cache completely kills the uncharge batching
> > because it reduces it to PAGEVEC_SIZE batches.
> >
> > I think we really do not need PAGEVEC_SIZE batching anymore. We are
> > already batching on tlb_gather layer. That one is limited so I think
> > the below should be safe but I have to think about this some more. There
> > is a risk of prolonged lru_lock wait times but the number of pages is
> > limited to 10k and the heavy work is done outside of the lock. If this
> > is really a problem then we can tear LRU part and the actual
> > freeing/uncharging into a separate functions in this path.
> >
> > Could you test with this half baked patch, please? I didn't get to test
> > it myself unfortunately.
>
> 3.16 settled out at about 11.5M faults/sec before the regression. This
> patch gets it back up to about 10.5M, which is good.
Dave, would you be willing to test the following patch as well? I do not
have a huge machine at hand right now. It would be great if you could
run the same load within a !root memcg. We have basically the same
sub-optimality there as well. The root bypass will be re-introduced for
now but I think we can make the regular memcg load better regardless and
this would be also preparation for later root bypass removal again.
---
next prev parent reply other threads:[~2014-09-05 9:25 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-02 19:05 Dave Hansen
2014-09-02 20:18 ` Dave Hansen
2014-09-02 20:57 ` Dave Hansen
2014-09-04 14:27 ` Michal Hocko
2014-09-04 20:27 ` Dave Hansen
2014-09-04 22:53 ` Dave Hansen
2014-09-05 9:28 ` Michal Hocko
2014-09-05 9:25 ` Michal Hocko [this message]
2014-09-05 14:47 ` Johannes Weiner
2014-09-05 15:39 ` Michal Hocko
2014-09-10 16:29 ` Michal Hocko
2014-09-10 16:57 ` Dave Hansen
2014-09-10 17:05 ` Michal Hocko
2014-09-05 12:35 ` Johannes Weiner
2014-09-08 15:47 ` Dave Hansen
2014-09-09 14:50 ` Johannes Weiner
2014-09-09 18:23 ` Dave Hansen
2014-09-02 22:18 ` Johannes Weiner
2014-09-02 22:36 ` Dave Hansen
2014-09-03 0:10 ` Johannes Weiner
2014-09-03 0:20 ` Linus Torvalds
2014-09-03 1:33 ` Johannes Weiner
2014-09-03 3:15 ` Dave Hansen
2014-09-03 0:30 ` Dave Hansen
2014-09-04 15:08 ` Johannes Weiner
2014-09-04 20:50 ` Dave Hansen
2014-09-05 8:04 ` Michal Hocko
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=20140905092537.GC26243@dhcp22.suse.cz \
--to=mhocko@suse.cz \
--cc=akpm@linux-foundation.org \
--cc=dave.hansen@intel.com \
--cc=dave@sr71.net \
--cc=hannes@cmpxchg.org \
--cc=hughd@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=vdavydov@parallels.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