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]
Date:	Tue, 16 Feb 2010 08:55:46 -0600 (CST)
From:	Christoph Lameter <cl@...ux-foundation.org>
To:	Mel Gorman <mel@....ul.ie>
cc:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Adam Litke <agl@...ibm.com>, Avi Kivity <avi@...hat.com>,
	David Rientjes <rientjes@...gle.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 05/12] Memory compaction core

On Tue, 16 Feb 2010, Mel Gorman wrote:

> Because how do I tell in advance that the data I am migrating from DMA can
> be safely relocated to the NORMAL zone? We don't save GFP flags. Granted,
> for DMA, that will not matter as pages that must be in DMA will also not by
> migratable. However, buffer pages should not get relocated to HIGHMEM for
> example which is more likely to happen. It could be special cased but
> I'm not aware of ZONE_DMA-related pressure problems that would make this
> worthwhile and if so, it should be handled as a separate patch series.

Oh there are numerous ZONE_DMA pressure issues if you have ancient /
screwed up hardware that can only operate on DMA or DMA32 memory.

Moving page cache pages out of the DMA zone would be good. A
write request will cause the page to bounce back to the DMA zone if the
device requires the page there.

But I also think that the patchset should be as simple as possible so that
it can be merged soon.

> Ah, it was 2009 when I last kicked this around heavily :) I'll update
> it.

But it was authored in 2009. May be important if patent or other
copyright claims arise. 2009-2010?

--
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/

Powered by blists - more mailing lists