From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-mm@kvack.org
Subject: Re: [PATCH] thp, vmstats: count deferred split events
Date: Wed, 10 Feb 2016 13:22:57 +0200 [thread overview]
Message-ID: <20160210112256.GA26440@node.shutemov.name> (raw)
In-Reply-To: <20160209132012.db18cdd7203b1d8b29483657@linux-foundation.org>
On Tue, Feb 09, 2016 at 01:20:12PM -0800, Andrew Morton wrote:
> On Tue, 9 Feb 2016 12:15:02 +0300 "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> wrote:
>
> > Counts how many times we put a THP in split queue. Currently, it happens
> > on partial unmap of a THP.
>
> Why do we need this?
Rapidly growing value can indicate that an application behaves
unfriendly wrt THP: often fault in huge page and then unmap part of it.
This leads to unnecessary memory fragmentation and the application may
require tuning.
Before refcouting rework thp_split_page would indicate the same. Not so much
now as we don't split huge pages that often.
The event also can help with debugging kernel [mis-]behaviour.
> > --- a/mm/vmstat.c
> > +++ b/mm/vmstat.c
> > @@ -847,6 +847,7 @@ const char * const vmstat_text[] = {
> > "thp_collapse_alloc_failed",
> > "thp_split_page",
> > "thp_split_page_failed",
> > + "thp_deferred_split_page",
> > "thp_split_pmd",
> > "thp_zero_page_alloc",
> > "thp_zero_page_alloc_failed",
>
> Documentation/vm/transhuge.txt, please.
Updated patch is below.
> While you're in there please > check that we haven't missed anything else.
The rest of the documents is up-to-date.
prev parent reply other threads:[~2016-02-10 11:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-09 9:15 [PATCH] thp, vmstats: count deferred split events Kirill A. Shutemov
2016-02-09 21:20 ` Andrew Morton
2016-02-10 11:22 ` Kirill A. Shutemov [this message]
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=20160210112256.GA26440@node.shutemov.name \
--to=kirill@shutemov.name \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-mm@kvack.org \
/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).