linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: Alex Samad <alex@samad.com.au>
Cc: linux-kernel@vger.kernel.org, linux-mm <linux-mm@kvack.org>,
	Mel Gorman <mel@skynet.ie>
Subject: Re: page swap allocation error/failure in 2.6.25
Date: Mon, 28 Jul 2008 12:04:47 +0200	[thread overview]
Message-ID: <1217239487.6331.24.camel@twins> (raw)
In-Reply-To: <20080727060701.GA7157@samad.com.au>

On Sun, 2008-07-27 at 16:07 +1000, Alex Samad wrote:
> On Fri, Jul 25, 2008 at 09:40:01AM +0200, Peter Zijlstra wrote:
> > On Fri, 2008-07-25 at 17:20 +1000, Alex Samad wrote:
> > > Hi
> 
> [snip]
> 
> > 
> > 
> > Its harmless if it happens sporadically. 
> > 
> > Atomic order 2 allocations are just bound to go wrong under pressure.
> can you point me to any doco that explains this ?

An order 2 allocation means allocating 1<<2 or 4 physically contiguous
pages. Atomic allocation means not being able to sleep.

Now if the free page lists don't have any order 2 pages available due to
fragmentation there is currently nothing we can do about it.

I've been meaning to try and play with 'atomic' page migration to try
and assemble a higher order page on demand with something like memory
compaction.

But its never managed to get high enough on the todo list..


  reply	other threads:[~2008-07-28 10:04 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-07-25  7:20 page swap allocation error/failure in 2.6.25 Alex Samad
2008-07-25  7:40 ` Peter Zijlstra
2008-07-27  6:07   ` Alex Samad
2008-07-28 10:04     ` Peter Zijlstra [this message]
2008-07-29  0:06       ` Alex Samad
2008-07-29  9:14         ` Mel Gorman
2008-07-29  9:58           ` Alex Samad

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=1217239487.6331.24.camel@twins \
    --to=peterz@infradead.org \
    --cc=alex@samad.com.au \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mel@skynet.ie \
    /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).