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Date: Fri, 07 Dec 2012 16:49:56 -0800 From: John Stultz <john.stultz@...aro.org> To: Minchan Kim <minchan@...nel.org> CC: Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org, linux-mm@...ck.org, Christoph Lameter <cl@...ux.com>, Android Kernel Team <kernel-team@...roid.com>, Robert Love <rlove@...gle.com>, Mel Gorman <mel@....ul.ie>, Hugh Dickins <hughd@...gle.com>, Dave Hansen <dave@...ux.vnet.ibm.com>, Rik van Riel <riel@...hat.com>, Dave Chinner <david@...morbit.com>, Neil Brown <neilb@...e.de>, Mike Hommey <mh@...ndium.org>, Taras Glek <tglek@...illa.com>, KOSAKI Motohiro <kosaki.motohiro@...il.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com> Subject: Re: [RFC v2] Support volatile range for anon vma On 12/04/2012 08:18 PM, Minchan Kim wrote: > On Tue, Dec 04, 2012 at 11:13:40AM -0800, John Stultz wrote: >> I don't think the problem is when vmas being marked VM_VOLATILE are >> being merged, its that when we mark the vma as *non-volatile*, and >> remove the VM_VOLATILE flag we merge the non-volatile vmas with >> neighboring vmas. So preserving the purged flag during that merge is >> important. Again, the example I used to trigger this was an >> alternating pattern of volatile and non volatile vmas, then marking >> the entire range non-volatile (though sometimes in two overlapping >> passes). > Understood. Thanks. > Below patch solves your problems? It's simple than yours. Yea, this is nicer then my fix. Although I still need the purged handling in the vma merge code for me to see the behavior I expect in my tests. I've integrated your patch and repushed my queue here: http://git.linaro.org/gitweb?p=people/jstultz/android-dev.git;a=shortlog;h=refs/heads/dev/minchan-anonvol git://git.linaro.org/people/jstultz/android-dev.git dev/minchan-anonvol > Anyway, both yours and mine are not right fix. > As I mentioned, locking scheme is broken. > We need anon_vma_lock to handle purged and we should consider fork > case, too. Hrm. I'm sure you're right, as I've not yet fully grasped all the locking rules here. Could you clarify how it is broken? And why is the anon_vma_lock needed to manage the purged state that is part of the vma itself? thanks -john -- 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/
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