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: <200708211051.36569.dave.mccracken@oracle.com>
Date:	Tue, 21 Aug 2007 10:51:35 -0500
From:	Dave McCracken <dave.mccracken@...cle.com>
To:	Christoph Lameter <clameter@....com>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC 0/7] Postphone reclaim laundry to write at high water marks

On Monday 20 August 2007, Christoph Lameter wrote:
> 1. First reclaiming non dirty pages. Dirty pages are deferred until reclaim
>    has reestablished the high marks. Then all the dirty pages (the laundry)
>    is written out.

I don't buy it.  What happens when there aren't enough clean pages in the 
system to achieve the high water mark?  I'm guessing we'd get a quick OOM (as 
observed by Peter).

> 2. Reclaim is essentially complete during the writeout phase. So we remove
>    PF_MEMALLOC and allow recursive reclaim if we still run into trouble
>    during writeout.

You're assuming the system is static and won't allocate new pages behind your 
back.  We could be back to critically low memory before the write happens.

More broadly, we need to be proactive about getting dirty pages cleaned before 
they consume the system.  Deferring the write just makes it harder to keep 
up.

Dave McCracken
-
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

Powered by Openwall GNU/*/Linux Powered by OpenVZ