linux-kernel - Re: [PATCH 1/7] dm: use __GFP_HIGH instead PF

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

Message-ID: <20091117131527.GB6644@agk-dp.fab.redhat.com>
Date:	Tue, 17 Nov 2009 13:15:28 +0000
From:	Alasdair G Kergon <agk@...hat.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	LKML <linux-kernel@...r.kernel.org>, linux-mm <linux-mm@...ck.org>,
	Andrew Morton <akpm@...ux-foundation.org>, dm-devel@...hat.com
Subject: Re: [PATCH 1/7] dm: use __GFP_HIGH instead PF_MEMALLOC

On Tue, Nov 17, 2009 at 04:17:07PM +0900, KOSAKI Motohiro wrote:
> Non MM subsystem must not use PF_MEMALLOC. Memory reclaim need few
> memory, anyone must not prevent it. Otherwise the system cause
> mysterious hang-up and/or OOM Killer invokation.

This code is also on the critical path, for example, if you are swapping
onto a dm device.  (There are ways we could reduce its use further as
not every dm ioctl needs to be on the critical path and the buffer size
could be limited for the ioctls that do.)

But what situations have been causing you trouble?  The OOM killer must
generally avoid killing userspace processes that suspend & resume dm
devices, and there are tight restrictions on what those processes
can do safely between suspending and resuming.

Alasdair

--
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/