linux-kernel - Re: Vanilla-Kernel 3 - page allocation failure

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <alpine.DEB.2.00.1110271302330.7639@chino.kir.corp.google.com>
Date:	Thu, 27 Oct 2011 13:08:32 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Philipp Herz - Profihost AG <p.herz@...fihost.ag>
cc:	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org,
	s.priebe@...fihost.ag
Subject: Re: Vanilla-Kernel 3 - page allocation failure

On Thu, 27 Oct 2011, Philipp Herz - Profihost AG wrote:

> > It won't be triggered synchronously in this context since it's a
> > GFP_ATOMIC allocation, which is why it emits a page allocation failure in
> > the first place, but it will show whether defragmentation is the issue or
> > you're just simply low on memory.
> Do you mean that "memory compaction" should be turned off again?
> 

No, I mean the difference since 2.6.32 might be that lumpy reclaim was 
deprecated so it is no longer causing high-order page allocations to be 
free in atomic context where no balancing or migration can synchronously 
be done.

> How can I see the difference between "deframentation issue" and "low memory"?
> I did not get this point.
> 

unusable_index and extfrag_index in debugfs if you've enabled and mounted 
that.  You could also take a look at tweaking 
/proc/sys/vm/extfrag_threshold, see Documentation/sysctl/vm.txt.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/