From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 17 Jan 2007 11:43:42 -0800 (PST) From: Christoph Lameter Subject: Re: [RFC 0/8] Cpuset aware writeback In-Reply-To: <20070116230034.b8cb4263.akpm@osdl.org> Message-ID: References: <20070116054743.15358.77287.sendpatchset@schroedinger.engr.sgi.com> <20070116135325.3441f62b.akpm@osdl.org> <20070116154054.e655f75c.akpm@osdl.org> <20070116170734.947264f2.akpm@osdl.org> <20070116183406.ed777440.akpm@osdl.org> <20070116200506.d19eacf5.akpm@osdl.org> <20070116230034.b8cb4263.akpm@osdl.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: menage@google.com, linux-kernel@vger.kernel.org, nickpiggin@yahoo.com.au, linux-mm@kvack.org, ak@suse.de, pj@sgi.com, dgc@sgi.com List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org