From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754229AbbIETZE (ORCPT ); Sat, 5 Sep 2015 15:25:04 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:38739 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754140AbbIETYy (ORCPT ); Sat, 5 Sep 2015 15:24:54 -0400 Date: Sat, 5 Sep 2015 22:24:48 +0300 From: Ebru Akagunduz To: Rik van Riel , Vlastimil Babka Cc: akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com, aarcange@redhat.com, iamjoonsoo.kim@lge.com, xiexiuqi@huawei.com, gorcunov@openvz.org, linux-kernel@vger.kernel.org, mgorman@suse.de, rientjes@google.com, aneesh.kumar@linux.vnet.ibm.com, hughd@google.com, hannes@cmpxchg.org, mhocko@suse.cz, boaz@plexistor.com, raindel@mellanox.com, linux-mm@kvack.org Subject: Re: [RESEND RFC v4 1/3] mm: add tracepoint for scanning pages Message-ID: <20150905192448.GA3933@debian> References: <1441313508-4276-1-git-send-email-ebru.akagunduz@gmail.com> <1441313508-4276-2-git-send-email-ebru.akagunduz@gmail.com> <55E9C1AA.4010908@suse.cz> <55E9CA8B.7090004@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55E9CA8B.7090004@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 04, 2015 at 12:44:59PM -0400, Rik van Riel wrote: > On 09/04/2015 12:07 PM, Vlastimil Babka wrote: > > On 09/03/2015 10:51 PM, Ebru Akagunduz wrote: > >> Using static tracepoints, data of functions is recorded. > >> It is good to automatize debugging without doing a lot > >> of changes in the source code. > >> > >> This patch adds tracepoint for khugepaged_scan_pmd, > >> collapse_huge_page and __collapse_huge_page_isolate. > >> > >> Signed-off-by: Ebru Akagunduz > >> Acked-by: Kirill A. Shutemov > >> Acked-by: Rik van Riel > >> --- > >> Changes in v2: > >> - Nothing changed > >> > >> Changes in v3: > >> - Print page address instead of vm_start (Vlastimil Babka) > >> - Define constants to specify exact tracepoint result (Vlastimil Babka) > >> > >> Changes in v4: > >> - Change the constant prefix with SCAN_ instead of MM_ (Vlastimil Babka) > >> - Move the constants into the enum (Vlastimil Babka) > >> - Move the constants from mm.h to huge_memory.c > >> (because only will be used in huge_memory.c) (Vlastimil Babka) > >> - Print pfn in tracepoints (Vlastimil Babka) > >> - Print scan result as string in tracepoint (Vlastimil Babka) > >> (I tried to make same things to print string like mm/compaction.c. > >> My patch does not print string, I skip something but could not see why) > > > > How do you print the trace? Do you cat /sys/kernel/debug/tracing/trace_pipe > > or use some tool such as trace-cmd? I have just recently realized that tools > > don't print strings in the compaction tracepoints, which lead to a patch [1]. > > You could convert this patch in the same way and then it should work with > > tracing tools. Sorry for previously suggesting a wrong example to follow. > > > > [1] https://lkml.org/lkml/2015/8/27/373 I use perf tool to test changes. > > Well that explains why doing the same thing as compaction.c > resulted in the strings not being printed! Ebru and I got > confused over that for quite a while :) > > Thanks for pointing us to the fix. > > Ebru, can you use tracepoint macros like in Vlastimil's patch > above, so your tracepoints work? > I did similar changes with Vlastimil's patch. It works! Thanks, Ebru