From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 047296B004D for ; Fri, 23 Oct 2009 07:31:13 -0400 (EDT) Date: Fri, 23 Oct 2009 13:31:10 +0200 (CEST) From: Tobias Oetiker Subject: Re: [PATCH 4/5] page allocator: Pre-emptively wake kswapd when high-order watermarks are hit In-Reply-To: <20091023112512.GW11778@csn.ul.ie> Message-ID: References: <1256221356-26049-1-git-send-email-mel@csn.ul.ie> <1256221356-26049-5-git-send-email-mel@csn.ul.ie> <20091023091334.GV11778@csn.ul.ie> <20091023112512.GW11778@csn.ul.ie> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: David Rientjes , Frans Pop , Jiri Kosina , Sven Geggus , Karol Lewandowski , "Rafael J. Wysocki" , David Miller , Reinette Chatre , Kalle Valo , KOSAKI Motohiro , Mohamed Abbas , Jens Axboe , "John W. Linville" , Pekka Enberg , Bartlomiej Zolnierkiewicz , Greg Kroah-Hartman , Stephan von Krawczynski , Kernel Testers List , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "linux-mm@kvack.org" List-ID: Mel, Today Mel Gorman wrote: > On Fri, Oct 23, 2009 at 02:36:53AM -0700, David Rientjes wrote: > > On Fri, 23 Oct 2009, Mel Gorman wrote: > > > > > > Hmm, is this really supposed to be added to __alloc_pages_high_priority()? > > > > By the patch description I was expecting kswapd to be woken up > > > > preemptively whenever the preferred zone is below ALLOC_WMARK_LOW and > > > > we're known to have just allocated at a higher order, not just when > > > > current was oom killed (when we should already be freeing a _lot_ of > > > > memory soon) or is doing a higher order allocation during direct reclaim. > > > > > > > > > > It was a somewhat arbitrary choice to have it trigger in the event high > > > priority allocations were happening frequently. > > > > > > > I don't quite understand, users of PF_MEMALLOC shouldn't be doing these > > higher order allocations and if ALLOC_NO_WATERMARKS is by way of the oom > > killer, we should be freeing a substantial amount of memory imminently > > when it exits that waking up kswapd would be irrelevant. > > > > I agree. I think it's highly unlikely this patch will make any > difference but I wanted to eliminate it as a possibility. Patch 3 and 4 > were previously one patch that were tested together. hi hi ... I have tested '3 only' this morning, and the allocation problems started again ... so for me 3 alone does not work while 3+4 does. cheers tobi -- Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland http://it.oetiker.ch tobi@oetiker.ch ++41 62 775 9902 / sb: -9900 -- 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