From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f171.google.com (mail-ig0-f171.google.com [209.85.213.171]) by kanga.kvack.org (Postfix) with ESMTP id 7E4156B0255 for ; Fri, 4 Sep 2015 12:45:06 -0400 (EDT) Received: by igcpb10 with SMTP id pb10so20752271igc.1 for ; Fri, 04 Sep 2015 09:45:06 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id lw2si5174224pdb.44.2015.09.04.09.45.05 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 04 Sep 2015 09:45:05 -0700 (PDT) Message-ID: <55E9CA8B.7090004@redhat.com> Date: Fri, 04 Sep 2015 12:44:59 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [RESEND RFC v4 1/3] mm: add tracepoint for scanning pages 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> In-Reply-To: <55E9C1AA.4010908@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka , Ebru Akagunduz , linux-mm@kvack.org 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 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 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? -- All rights reversed -- 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