From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f50.google.com (mail-pa0-f50.google.com [209.85.220.50]) by kanga.kvack.org (Postfix) with ESMTP id 46377828DF for ; Tue, 12 Jan 2016 15:00:57 -0500 (EST) Received: by mail-pa0-f50.google.com with SMTP id cy9so344886319pac.0 for ; Tue, 12 Jan 2016 12:00:57 -0800 (PST) Received: from mail-pa0-x231.google.com (mail-pa0-x231.google.com. [2607:f8b0:400e:c03::231]) by mx.google.com with ESMTPS id bw10si26820068pab.22.2016.01.12.12.00.56 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Jan 2016 12:00:56 -0800 (PST) Received: by mail-pa0-x231.google.com with SMTP id uo6so328475096pac.1 for ; Tue, 12 Jan 2016 12:00:56 -0800 (PST) Subject: Re: [RFC V5] Add gup trace points support References: <1449696151-4195-1-git-send-email-yang.shi@linaro.org> From: "Shi, Yang" Message-ID: <56955B76.2060503@linaro.org> Date: Tue, 12 Jan 2016 12:00:54 -0800 MIME-Version: 1.0 In-Reply-To: <1449696151-4195-1-git-send-email-yang.shi@linaro.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, rostedt@goodmis.org, mingo@redhat.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linaro-kernel@lists.linaro.org Hi Steven, Any more comments on this series? How should I proceed it? Thanks, Yang On 12/9/2015 1:22 PM, Yang Shi wrote: > v5: > * Fixed a typo introduced by v4 rebase > * Removed redundant "#define CREATE_TRACE_POINTS" from architecture specifc > gup.c > > v4: > * Adopted Steven's suggestion to use "unsigned int" for nr_pages to save > space in ring buffer since it is unlikely to have more than 0xffffffff > pages are touched by gup in one invoke > * Remove unnecessray type cast > > v3: > * Adopted suggestion from Dave Hansen to move the gup header include to the last > * Adopted comments from Steven: > - Use DECLARE_EVENT_CLASS and DEFINE_EVENT > - Just keep necessary TP_ARGS > * Moved archtichture specific fall-backable fast version trace point after the > do while loop since it may jump to the slow version. > * Not implement recording return value since Steven plans to have it in generic > tracing code > > v2: > * Adopted commetns from Steven > - remove all reference to tsk->comm since it is unnecessary for non-sched > trace points > - reduce arguments for __get_user_pages trace point and update mm/gup.c > accordingly > * Added Ralf's acked-by for patch 4/7. > > > Some background about why I think this might be useful. > > When I was profiling some hugetlb related program, I got page-faults event > doubled when hugetlb is enabled. When I looked into the code, I found page-faults > come from two places, do_page_fault and gup. So, I tried to figure out which > play a role (or both) in my use case. But I can't find existing finer tracing > event for sub page-faults in current mainline kernel. > > So, I added the gup trace points support to have finer tracing events for > page-faults. The below events are added: > > __get_user_pages > __get_user_pages_fast > fixup_user_fault > > Both __get_user_pages and fixup_user_fault call handle_mm_fault. > > Just added trace points to raw version __get_user_pages since all variants > will call it finally to do real work. > > Although __get_user_pages_fast doesn't call handle_mm_fault, it might be useful > to have it to distinguish between slow and fast version. > -- 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