From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 26 Jun 2007 11:21:57 -0700 (PDT) From: Christoph Lameter Subject: Re: [patch 15/26] Slab defrag: Support generic defragmentation for inode slab caches In-Reply-To: <20070626011836.f4abb4ff.akpm@linux-foundation.org> Message-ID: References: <20070618095838.238615343@sgi.com> <20070618095917.005535114@sgi.com> <20070626011836.f4abb4ff.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Pekka Enberg , suresh.b.siddha@intel.com List-ID: On Tue, 26 Jun 2007, Andrew Morton wrote: > > Provide generic functionality that can be used by filesystems that have > > their own inode caches to also tie into the defragmentation functions > > that are made available here. > > Yes, this is tricky stuff. I have vague ancestral memories that the sort > of inode work which you refer to here can cause various deadlocks, lockdep > warnings and such nasties when if we attempt to call it from the wrong > context (ie: from within fs code). Right that is likelyi the reason why Michael did his stress test... > Possibly we could prevent that by skipping all this code if the caller > didn't have __GFP_FS. We do. Look at the earlier patch. > I trust all the code in kick_inodes() was carefuly copied from > prue_icache() and such places - I didn't check it. Yup tried to remain faithful to that. We could increase the usefulness if I could take more liberties with the code in order to actually move an item instead of simply reclaiming. But its better to first have a proven correct solution before doing more work on that. -- 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