From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: The VFS cache is not freed when there is not enough free memory to allocate From: Peter Zijlstra In-Reply-To: <6d6a94c50611220202t1d076b4cye70dcdcc19f56e55@mail.gmail.com> References: <6d6a94c50611212351if1701ecx7b89b3fe79371554@mail.gmail.com> <1164185036.5968.179.camel@twins> <6d6a94c50611220202t1d076b4cye70dcdcc19f56e55@mail.gmail.com> Content-Type: text/plain Date: Wed, 22 Nov 2006 11:42:51 +0100 Message-Id: <1164192171.5968.186.camel@twins> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Aubrey Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, mel , Andy Whitcroft List-ID: On Wed, 2006-11-22 at 18:02 +0800, Aubrey wrote: > On 11/22/06, Peter Zijlstra wrote: > > Please see the > > threads on Mel Gorman's Anti-Fragmentation and Linear/Lumpy reclaim in > > the linux-mm archives. > > > > Thanks to point this. Is it already included in Linus' git tree? No it is not. > Well, the test application just use an exaggerated way to replicate the issue. > > Actually, In the real work, the application such as mplayer, asterisk, > etc will run into > the above problem when run them at the second time. I think I have no > reason to modify those kind of applications. It comes from the choice of architecture, I'd not run general purpose code like that on MMU-less hardware. But yeah, I see your point. > My patch let kernel drop VFS cache in the low memory situation when > the application requests more memory allocation, I don't think it's > luck. You know, the application just wants to allocate 8 > 1Mbyte-blocks(order =9) and releasing VFS cache we can get almost > 50Mbyte free memory. Yes it does that, but there is no guarantee that those 50MB have a single 1M contiguous region amongst them. > The patch indeedly enabled many failed test cases on our side. But > yes, I don't think it's the final solution. I'll try Mel's patch and > update the results. Mel's patches alone aren't quite enough, you also need some reclaim modifications, I'll ping Andy to see how far he's 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