From: Andrea Arcangeli <aarcange@redhat.com>
To: Nai Xia <nai.xia@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>, Hugh Dickins <hughd@google.com>,
Pawel Sikora <pluto@agmk.net>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, jpiszcz@lucidpixels.com, arekm@pld-linux.org,
linux-kernel@vger.kernel.org
Subject: Re: kernel 3.0: BUG: soft lockup: find_get_pages+0x51/0x110
Date: Mon, 31 Oct 2011 18:14:41 +0100 [thread overview]
Message-ID: <20111031171441.GD3466@redhat.com> (raw)
In-Reply-To: <201110221352.22741.nai.xia@gmail.com>
On Sat, Oct 22, 2011 at 01:52:22PM +0800, Nai Xia wrote:
> BTW, I am curious about what benchmark did you run and " x10 boost"
> meaning compared to Hugh's anon_vma_locking fix?
I was referring to the mremap optimizations I pushed in -mm.
> This patch and together with the reasoning looks good to me.
> But I wondering this patch can make the anon_vma chain ordering game more
> complex and harder to play in the future.
Well we don't know yet what future will bring... at least this adds
some documentation on the fact the order matters for
fork/mremap/migrate/split_huge_page. As far as I can tell they're the
4 pieces of the VM where the rmap_walk order matters. And
split_huge_page and migrate are the only two where if the rmap_walk
fails we can't safely continue and have to BUG_ON.
> However, if it does bring much perfomance benefit, I vote for this patch
> because it balances all three requirements here: bug free, performance &
> no two VMAs stay not merged for no good reason.
I suppose it should bring an SMP performance benefit as the critical
section is reduced but we'll have to do some more list_del/add_tail
than if we take the global lock...
> Our situation again makes me have the strong feeling that we are really
> in bad need of a computer aided way to travel all possible state space.
> There are some guys around me who do automatic software testing research.
> But I am afraid our problem is too much "real world" for them... sigh...
Also the code changes too fast for that...
I'll send the patch again with signoff.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2011-10-31 17:56 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <201110122012.33767.pluto@agmk.net>
[not found] ` <alpine.LSU.2.00.1110131547550.1346@sister.anvils>
2011-10-13 23:30 ` kernel 3.0: BUG: soft lockup: find_get_pages+0x51/0x110 Hugh Dickins
2011-10-16 16:11 ` Christoph Hellwig
2011-10-16 23:54 ` Andrea Arcangeli
2011-10-17 18:51 ` Hugh Dickins
2011-10-17 22:05 ` Andrea Arcangeli
2011-10-19 7:43 ` Mel Gorman
2011-10-19 13:39 ` Linus Torvalds
2011-10-19 19:42 ` Hugh Dickins
2011-10-20 6:30 ` Paweł Sikora
2011-10-20 6:51 ` Linus Torvalds
2011-10-21 6:54 ` Nai Xia
2011-10-21 7:35 ` Pawel Sikora
2011-10-20 12:51 ` Nai Xia
2011-10-20 18:36 ` Hugh Dickins
2011-10-21 6:22 ` Nai Xia
2011-10-21 8:07 ` Pawel Sikora
2011-10-21 9:07 ` Nai Xia
2011-10-21 21:36 ` Paweł Sikora
2011-10-22 6:21 ` Nai Xia
2011-10-22 16:42 ` Paweł Sikora
2011-10-20 9:11 ` Nai Xia
2011-10-21 15:56 ` Mel Gorman
2011-10-21 17:21 ` Nai Xia
2011-10-21 17:41 ` Andrea Arcangeli
2011-10-21 22:50 ` Andrea Arcangeli
2011-10-22 5:52 ` Nai Xia
2011-10-31 17:14 ` Andrea Arcangeli [this message]
2011-10-31 17:27 ` [PATCH] mremap: enforce rmap src/dst vma ordering in case of vma_merge succeeding in copy_vma Andrea Arcangeli
2011-11-01 12:07 ` Mel Gorman
2011-11-01 14:35 ` Nai Xia
2011-11-04 7:31 ` Hugh Dickins
2011-11-04 14:34 ` Nai Xia
2011-11-04 15:59 ` Pawel Sikora
2011-11-05 2:21 ` Nai Xia
2011-11-04 19:16 ` Hugh Dickins
2011-11-04 20:54 ` Andrea Arcangeli
2011-11-05 0:09 ` Nai Xia
2011-11-05 2:21 ` Hugh Dickins
2011-11-05 3:07 ` Andrea Arcangeli
2011-11-05 17:06 ` Andrea Arcangeli
2011-12-08 3:24 ` David Rientjes
2011-12-08 12:42 ` Andrea Arcangeli
2011-12-09 0:08 ` Andrew Morton
2011-12-09 1:55 ` Andrea Arcangeli
2011-11-04 23:56 ` Andrea Arcangeli
2011-11-05 0:21 ` Nai Xia
2011-11-05 0:59 ` Nai Xia
2011-11-05 1:33 ` Andrea Arcangeli
2011-11-05 2:00 ` Nai Xia
2011-11-07 13:14 ` Mel Gorman
2011-11-07 15:42 ` Andrea Arcangeli
2011-11-07 16:28 ` Mel Gorman
2011-11-09 1:25 ` Andrea Arcangeli
2011-11-11 9:14 ` Nai Xia
2011-11-16 14:00 ` Andrea Arcangeli
2011-11-17 0:16 ` Hugh Dickins
2011-11-17 2:49 ` Nai Xia
2011-11-17 6:21 ` Nai Xia
2011-11-17 18:42 ` Andrea Arcangeli
2011-11-18 1:42 ` Nai Xia
2011-11-18 2:17 ` Andrea Arcangeli
2011-11-19 9:15 ` Nai Xia
2011-10-22 5:07 ` kernel 3.0: BUG: soft lockup: find_get_pages+0x51/0x110 Nai Xia
2011-10-31 16:34 ` Andrea Arcangeli
2011-10-16 22:37 ` Linus Torvalds
2011-10-17 3:02 ` Hugh Dickins
2011-10-17 3:09 ` Linus Torvalds
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=20111031171441.GD3466@redhat.com \
--to=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=arekm@pld-linux.org \
--cc=hughd@google.com \
--cc=jpiszcz@lucidpixels.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=nai.xia@gmail.com \
--cc=pluto@agmk.net \
/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).