From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 0F5456B03A7 for ; Mon, 23 Aug 2010 05:10:03 -0400 (EDT) Received: by iwn33 with SMTP id 33so4197321iwn.14 for ; Mon, 23 Aug 2010 02:10:02 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20100817111018.GQ19797@csn.ul.ie> <4385155269B445AEAF27DC8639A953D7@rainbow> <20100818154130.GC9431@localhost> <565A4EE71DAC4B1A820B2748F56ABF73@rainbow> <20100819160006.GG6805@barrios-desktop> <20100820053447.GA13406@localhost> <20100820093558.GG19797@csn.ul.ie> <20100822153121.GA29389@barrios-desktop> <20100822232316.GA339@localhost> Date: Mon, 23 Aug 2010 18:10:02 +0900 Message-ID: Subject: Re: compaction: trying to understand the code From: Minchan Kim Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org To: Iram Shahzad Cc: Wu Fengguang , Mel Gorman , Andrew Morton , linux-mm@kvack.org, KOSAKI Motohiro List-ID: On Mon, Aug 23, 2010 at 12:03 PM, Iram Shahzad wrote: >> Iram. How do you execute test_app? >> >> 1) synchronous test >> 1.1 start test_app >> 1.2 wait test_app job done (ie, wait memory is fragment) >> 1.3 echo 1 > /proc/sys/vm/compact_memory >> >> 2) asynchronous test >> 2.1 start test_app >> 2.2 not wait test_app job done >> 2.3 echo 1 > /proc/sys/vm/compact_memory(Maybe your test app and >> compaction were executed parallel) > > It's synchronous. > First I confirm that the test app has completed its fragmentation work > by looking at the printf output. Then only I run echo 1 > > /proc/sys/vm/compact_memory. > > After completing fragmentation work, my test app sleeps in a useless while > loop > which I think is not important. Thanks. It seems to be not any other processes which is entering direct reclaiming. I tested your test_app but failed to reproduce your problem. Actually I suspected some leak of decrease NR_ISOLATE_XXX but my system worked well. And I couldn't find the point as just code reviewing. If it really was, Mel found it during his stress test. Hmm.. Mystery. Maybe we need some tracepoint to debug. -- Kind regards, Minchan Kim -- 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