From: Michal Hocko <mhocko@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Lukasz Odzioba <lukasz.odzioba@intel.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, kirill.shutemov@linux.intel.com,
aarcange@redhat.com, vdavydov@parallels.com, mingli199x@qq.com,
minchan@kernel.org, lukasz.anaczkowski@intel.com, "Shutemov,
Kirill" <kirill.shutemov@intel.com>
Subject: Re: [PATCH 1/1] mm/swap.c: flush lru_add pvecs on compound page arrival
Date: Thu, 9 Jun 2016 14:21:41 +0200 [thread overview]
Message-ID: <20160609122140.GE24777@dhcp22.suse.cz> (raw)
In-Reply-To: <575848F9.2060501@intel.com>
On Wed 08-06-16 09:34:01, Dave Hansen wrote:
> On 06/08/2016 09:06 AM, Michal Hocko wrote:
> >> > Do we have any statistics that tell us how many pages are sitting the
> >> > lru pvecs? Although this helps the problem overall, don't we still have
> >> > a problem with memory being held in such an opaque place?
> > Is it really worth bothering when we are talking about 56kB per CPU
> > (after this patch)?
>
> That was the logic why we didn't have it up until now: we didn't
> *expect* it to get large. A code change blew it up by 512x, and we had
> no instrumentation to tell us where all the memory went.
>
> I guess we don't have any other ways to group pages than compound pages,
> and _that_ one is covered now...
exactly and that is why I am not sure it is needed. I do not expect we
would ever change the pagevec size or have a different way of grouping
pages on the LRU list.
That being said I am not objecting to the counter, I am just not sure it
is worth it.
> for one of the 5 classes of pvecs.
>
> Is there a good reason we don't have to touch the other 4 pagevecs, btw?
I agree it would be better to do the same for others as well. Even if
this is not an immediate problem for those.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-06-09 12:21 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-08 14:35 [PATCH 1/1] mm/swap.c: flush lru_add pvecs on compound page arrival Lukasz Odzioba
2016-06-08 15:04 ` Michal Hocko
2016-06-09 8:01 ` Odzioba, Lukasz
2016-06-08 15:31 ` Dave Hansen
2016-06-08 16:06 ` Michal Hocko
2016-06-08 16:34 ` Dave Hansen
2016-06-09 12:21 ` Michal Hocko [this message]
2016-06-16 18:08 ` Odzioba, Lukasz
2016-06-16 18:19 ` Michal Hocko
2016-06-16 20:03 ` Odzioba, Lukasz
2016-06-09 8:50 ` Odzioba, Lukasz
2016-06-09 15:41 ` Dave Hansen
2016-06-13 21:01 ` Odzioba, Lukasz
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=20160609122140.GE24777@dhcp22.suse.cz \
--to=mhocko@kernel.org \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=dave.hansen@intel.com \
--cc=kirill.shutemov@intel.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lukasz.anaczkowski@intel.com \
--cc=lukasz.odzioba@intel.com \
--cc=minchan@kernel.org \
--cc=mingli199x@qq.com \
--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;
as well as URLs for NNTP newsgroup(s).