From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755674AbZHKXdk (ORCPT ); Tue, 11 Aug 2009 19:33:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754309AbZHKXdk (ORCPT ); Tue, 11 Aug 2009 19:33:40 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:59475 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754021AbZHKXdj (ORCPT ); Tue, 11 Aug 2009 19:33:39 -0400 Date: Wed, 12 Aug 2009 08:31:02 +0900 (JST) X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Mel Gorman Subject: Re: [PATCH 1/6] tracing, page-allocator: Add trace events for page allocation and page freeing Cc: kosaki.motohiro@jp.fujitsu.com, Larry Woodman , Ingo Molnar , Andrew Morton , riel@redhat.com, Peter Zijlstra , Li Ming Chun , LKML , linux-mm@kvack.org In-Reply-To: <1249918915-16061-2-git-send-email-mel@csn.ul.ie> References: <1249918915-16061-1-git-send-email-mel@csn.ul.ie> <1249918915-16061-2-git-send-email-mel@csn.ul.ie> Message-Id: <20090811163939.9ADF.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > This patch adds trace events for the allocation and freeing of pages, > including the freeing of pagevecs. Using the events, it will be known what > struct page and pfns are being allocated and freed and what the call site > was in many cases. > > The page alloc tracepoints be used as an indicator as to whether the workload > was heavily dependant on the page allocator or not. You can make a guess based > on vmstat but you can't get a per-process breakdown. Depending on the call > path, the call_site for page allocation may be __get_free_pages() instead > of a useful callsite. Instead of passing down a return address similar to > slab debugging, the user should enable the stacktrace and seg-addr options > to get a proper stack trace. > > The pagevec free tracepoint has a different usecase. It can be used to get > a idea of how many pages are being dumped off the LRU and whether it is > kswapd doing the work or a process doing direct reclaim. Looks good to me. Reviewed-by: KOSAKI Motohiro