From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 4 Nov 2005 09:38:33 -0800 From: Andrew Morton Subject: Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19 Message-Id: <20051104093833.0db634f0.akpm@osdl.org> In-Reply-To: <325200000.1131117596@[10.10.2.4]> References: <200511021747.45599.rob@landley.net> <43699573.4070301@yahoo.com.au> <200511030007.34285.rob@landley.net> <20051103163555.GA4174@ccure.user-mode-linux.org> <1131035000.24503.135.camel@localhost.localdomain> <20051103205202.4417acf4.akpm@osdl.org> <20051103213538.7f037b3a.pj@sgi.com> <20051103214807.68a3063c.akpm@osdl.org> <20051103224239.7a9aee29.pj@sgi.com> <20051103231019.488127a6.akpm@osdl.org> <325200000.1131117596@[10.10.2.4]> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: "Martin J. Bligh" Cc: pj@sgi.com, bron@bronze.corp.sgi.com, pbadari@gmail.com, jdike@addtoit.com, rob@landley.net, nickpiggin@yahoo.com.au, gh@us.ibm.com, mingo@elte.hu, kamezawa.hiroyu@jp.fujitsu.com, haveblue@us.ibm.com, mel@csn.ul.ie, kravetz@us.ibm.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, lhms-devel@lists.sourceforge.net List-ID: "Martin J. Bligh" wrote: > > > Seriously, it does appear that doing it per-task is adequate for your > > needs, and it is certainly more general. > > > > > > > > I cannot understand why you decided to count only the number of > > direct-reclaim events, via a "digitally filtered, constant time based, > > event frequency meter". > > > > a) It loses information. If we were to export the number of pages > > reclaimed from the mm, filtering can be done in userspace. > > > > b) It omits reclaim performed by kswapd and by other tasks (ok, it's > > very cpuset-specific). > > > > c) It only counts synchronous try_to_free_pages() attempts. What if an > > attempt only freed pagecache, or didbn't manage to free anything? > > > > d) It doesn't notice if kswapd is swapping the heck out of your > > not-allocating-any-memory-now process. > > > > > > I think all the above can be addressed by exporting per-task (actually > > per-mm) reclaim info. (I haven't put much though into what info that > > should be - page reclaim attempts, mmapped reclaims, swapcache reclaims, > > etc) > > I've been looking at similar things. When we page out / free something from > a shared library that 10 tasks have mapped, who does that count against > for pressure? Count pte unmappings and minor faults and account them against the mm_struct, I guess. -- 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