linux-kernel - Re: [RFC 0/8] Cpuset aware writeback

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: <Pine.LNX.4.64.0701171140580.7397@schroedinger.engr.sgi.com>
Date:	Wed, 17 Jan 2007 11:43:42 -0800 (PST)
From:	Christoph Lameter <clameter@....com>
To:	Andrew Morton <akpm@...l.org>
cc:	menage@...gle.com, linux-kernel@...r.kernel.org,
	nickpiggin@...oo.com.au, linux-mm@...ck.org, ak@...e.de,
	pj@....com, dgc@....com
Subject: Re: [RFC 0/8] Cpuset aware writeback

On Tue, 16 Jan 2007, Andrew Morton wrote:

> Do what blockdevs do: limit the number of in-flight requests (Peter's
> recent patch seems to be doing that for us) (perhaps only when PF_MEMALLOC
> is in effect, to keep Trond happy) and implement a mempool for the NFS
> request critical store.  Additionally:
> 
> - we might need to twiddle the NFS gfp_flags so it doesn't call the
>   oom-killer on failure: just return NULL.
> 
> - consider going off-cpuset for critical allocations.  It's better than
>   going oom.  A suitable implementation might be to ignore the caller's
>   cpuset if PF_MEMALLOC.  Maybe put a WARN_ON_ONCE in there: we prefer that
>   it not happen and we want to know when it does.

Given the intermediate  layers (network, additional gizmos (ip over xxx) 
and the network cards) that will not be easy.

> btw, regarding the per-address_space node mask: I think we should free it
> when the inode is clean (!mapping_tagged(PAGECACHE_TAG_DIRTY)).  Chances
> are, the inode will be dirty for 30 seconds and in-core for hours.  We
> might as well steal its nodemask storage and give it to the next file which
> gets written to.  A suitable place to do all this is in
> __mark_inode_dirty(I_DIRTY_PAGES), using inode_lock to protect
> address_space.dirty_page_nodemask.

The inode lock is not taken when the page is dirtied. The tree_lock
is already taken when the mapping is dirtied and so I used that to
avoid races adding and removing pointers to nodemasks from the address 
space.
-
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/