From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f175.google.com (mail-pf0-f175.google.com [209.85.192.175]) by kanga.kvack.org (Postfix) with ESMTP id 0C2DE6B0038 for ; Wed, 9 Dec 2015 16:42:22 -0500 (EST) Received: by pfdd184 with SMTP id d184so36142149pfd.3 for ; Wed, 09 Dec 2015 13:42:21 -0800 (PST) Received: from mail-pa0-x229.google.com (mail-pa0-x229.google.com. [2607:f8b0:400e:c03::229]) by mx.google.com with ESMTPS id d3si15104082pas.116.2015.12.09.13.42.21 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Dec 2015 13:42:21 -0800 (PST) Received: by pacdm15 with SMTP id dm15so35951790pac.3 for ; Wed, 09 Dec 2015 13:42:21 -0800 (PST) From: Yang Shi Subject: [RFC V5] Add gup trace points support Date: Wed, 9 Dec 2015 13:22:24 -0800 Message-Id: <1449696151-4195-1-git-send-email-yang.shi@linaro.org> 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, yang.shi@linaro.org 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