From: Ingo Molnar <mingo@elte.hu>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>,
Christoph Lameter <clameter@sgi.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@infradead.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>
Subject: Re: Major regression on hackbench with SLUB (more numbers)
Date: Sat, 22 Dec 2007 20:09:33 +0100 [thread overview]
Message-ID: <20071222190933.GA2958@elte.hu> (raw)
In-Reply-To: <alpine.LFD.0.9999.0712220937560.21557@woody.linux-foundation.org>
* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> > > It's definitely not a stable ABI. slabtop tends to exit without
> > > any error message on any slabinfo version number increase and I've
> > > seen that happen several times in not so old kernels.
> >
> > so because we sucked in the past we can continue to suck? ;)
>
> Well, I do have to admit that I'm not a huge fan of /proc/slabinfo,
> and the fact that there hasn't been a lot of complaints about it going
> away does seem to imply that it wasn't a very important ABI.
>
> I'm the first to stand up for backwards compatibility, but I also try
> to be realistic, and so far nobody has really complained about the
> fact that /proc/slabinfo went away on any grounds but on the general
> principle of "it was a user-visible ABI".
>
> We've changed user-visible ABI's in the past in the hope that they
> weren't actually used. Sometimes it worked, sometimes it didn't. In
> this case, I think it still has the potential of working.
>
> That said, I'm not a *huge* fan of /sys/slab/ either. I can get the
> info I as a developer tend to want from there, but it's really rather
> less convenient than I'd like. It is really quite hard, for example,
> to get any kind of "who actually uses the most *memory*" information
> out of there.
Yes, i agree that me calling it an 'ABI' stretches the term - we dont
want to put ourselves into a forced compatibility corner in every case
where /proc does something really stupid. But /proc/slabinfo is being
used, slabtop is installed and deployed, so why break it unnecessarily?
It's not like we couldnt remove /proc/slabinfo later on, via the normal
route of feature removal. I think Pekka's patch that adds /proc/slabinfo
is simple and reasonable enough for 2.6.24.
We can get rid of /proc/slabinfo but then it should i think be done via
the normal route of Documentation/feature-removal-schedule.txt. Was
there any particular problem with /proc/slabinfo, at least as far as the
read-only access that slabtop does goes? I dont think there was. So why
should we go out on a limb _not_ providing it when there's a patch
available, etc. I just googled a bit and people _have_ asked about
slabtop availability, and the impression was that it would be offered by
the time SLUB becomes the default. (and this was mentioned by others in
this discussion)
I'd also not rely on the fact that only a few people are complaining.
Most people, even 2.6.24-rc early adopters, still use SLAB because early
adopters typically use their .23 .config and do a 'make oldconfig' -
which picks up SLAB. So SLUB use will become more widespread only once
2.6.24 is out and is packaged in distros. Distros will likely pick SLUB
if there's no performance worries and if it's the default. Fedora
rawhide already uses SLUB.
Ingo
next prev parent reply other threads:[~2007-12-22 19:15 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-07 17:50 Major regression on hackbench with SLUB Steven Rostedt
2007-12-07 17:55 ` Ingo Molnar
2007-12-07 17:59 ` Linus Torvalds
2007-12-07 18:36 ` Linus Torvalds
2007-12-07 18:58 ` Steven Rostedt
2007-12-08 22:16 ` Steven Rostedt
2007-12-10 7:38 ` Björn Steinbrink
2007-12-10 14:00 ` Steven Rostedt
2007-12-09 0:28 ` Steven Rostedt
2007-12-13 22:11 ` Christoph Lameter
2007-12-11 14:33 ` Major regression on hackbench with SLUB (more numbers) Ingo Molnar
2007-12-13 22:22 ` Christoph Lameter
2007-12-14 4:24 ` Christoph Lameter
2007-12-14 6:15 ` Steven Rostedt
2007-12-21 12:09 ` Ingo Molnar
2007-12-21 12:26 ` Ingo Molnar
2007-12-21 16:26 ` Christoph Lameter
2007-12-21 16:33 ` Ingo Molnar
2007-12-21 21:56 ` Christoph Lameter
2007-12-21 16:18 ` Christoph Lameter
2007-12-21 16:44 ` Linus Torvalds
2007-12-21 22:11 ` Christoph Lameter
2007-12-21 22:16 ` Peter Zijlstra
2007-12-21 22:17 ` Peter Zijlstra
2007-12-21 22:27 ` Christoph Lameter
2007-12-21 22:54 ` Ingo Molnar
2007-12-21 23:20 ` David Miller
2007-12-22 9:45 ` Ingo Molnar
2007-12-24 19:24 ` Christoph Lameter
2007-12-21 23:27 ` Andrew Morton
2007-12-21 23:51 ` Christoph Lameter
2007-12-22 0:28 ` Andi Kleen
2007-12-22 0:33 ` Chuck Ebbert
2007-12-22 2:19 ` Matt Mackall
2007-12-22 2:44 ` Andi Kleen
2007-12-22 10:03 ` Ingo Molnar
2007-12-22 12:37 ` Andi Kleen
2007-12-22 12:51 ` Pekka Enberg
2007-12-22 12:54 ` Andi Kleen
2007-12-22 13:27 ` Pekka Enberg
2007-12-22 13:01 ` Alexey Dobriyan
2007-12-22 18:01 ` Linus Torvalds
2007-12-22 19:09 ` Ingo Molnar [this message]
2007-12-22 19:29 ` Ingo Molnar
2007-12-22 22:52 ` Jason L Tibbitts III
2007-12-24 3:59 ` Alessandro Suardi
2007-12-22 19:25 ` Theodore Tso
2007-12-22 21:00 ` Linus Torvalds
2007-12-22 21:50 ` Al Viro
2007-12-22 23:29 ` Al Viro
2007-12-22 22:10 ` Willy Tarreau
2007-12-23 0:59 ` Steven Rostedt
2007-12-23 5:12 ` Willy Tarreau
2007-12-23 14:15 ` Andi Kleen
2007-12-24 3:45 ` Theodore Tso
2007-12-24 19:21 ` Christoph Lameter
2007-12-24 23:37 ` Theodore Tso
2007-12-25 3:34 ` Andi Kleen
2008-01-01 12:47 ` Theodore Tso
2008-01-01 15:19 ` Andi Kleen
2008-01-01 16:23 ` [patch] slub: provide /proc/slabinfo Ingo Molnar
2008-01-05 0:27 ` Arjan van de Ven
2008-01-05 0:49 ` Linus Torvalds
2007-12-26 21:31 ` Major regression on hackbench with SLUB (more numbers) Christoph Lameter
2007-12-26 22:16 ` Al Viro
2007-12-27 5:51 ` Christoph Lameter
2007-12-27 20:28 ` SLUB sysfs support Christoph Lameter
2007-12-27 22:59 ` Al Viro
2007-12-27 23:22 ` Christoph Lameter
2007-12-27 23:53 ` Christoph Lameter
2007-12-27 23:58 ` Al Viro
2007-12-28 0:02 ` Christoph Lameter
2007-12-28 0:45 ` Al Viro
2007-12-28 2:19 ` Christoph Lameter
2007-12-28 3:26 ` Al Viro
2008-01-02 20:25 ` Christoph Lameter
2007-12-27 23:54 ` Al Viro
2007-12-28 9:00 ` Major regression on hackbench with SLUB (more numbers) Ingo Molnar
2007-12-28 14:52 ` Steven Rostedt
2007-12-22 19:46 ` slabtop replacement was " Andi Kleen
2007-12-22 23:28 ` Karol Swietlicki
2007-12-29 18:08 ` Karol Swietlicki
2007-12-21 22:49 ` Linus Torvalds
2007-12-21 17:44 ` Pekka Enberg
2007-12-21 22:22 ` Christoph Lameter
2007-12-21 22:37 ` Christoph Lameter
2007-12-21 22:51 ` Linus Torvalds
2007-12-21 23:17 ` Ingo Molnar
2007-12-21 23:40 ` Pekka Enberg
2007-12-21 23:54 ` Christoph Lameter
2007-12-22 0:02 ` Chuck Ebbert
2007-12-21 22:52 ` Steven Rostedt
2007-12-21 22:56 ` Ingo Molnar
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=20071222190933.GA2958@elte.hu \
--to=mingo@elte.hu \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=andi@firstfloor.org \
--cc=clameter@sgi.com \
--cc=hch@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rjw@sisk.pl \
--cc=rostedt@goodmis.org \
--cc=torvalds@linux-foundation.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).