From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f70.google.com (mail-oi0-f70.google.com [209.85.218.70]) by kanga.kvack.org (Postfix) with ESMTP id 289C16B0292 for ; Fri, 1 Sep 2017 01:00:31 -0400 (EDT) Received: by mail-oi0-f70.google.com with SMTP id b184so3820586oih.3 for ; Thu, 31 Aug 2017 22:00:31 -0700 (PDT) Received: from smtp.codeaurora.org (smtp.codeaurora.org. [198.145.29.96]) by mx.google.com with ESMTPS id b143si1113433oii.529.2017.08.31.22.00.29 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 31 Aug 2017 22:00:29 -0700 (PDT) Subject: Re: [PATCH 2/2] mm, page_owner: Skip unnecessary stack_trace entries References: <1504078343-28754-1-git-send-email-guptap@codeaurora.org> <1504078343-28754-2-git-send-email-guptap@codeaurora.org> <82346e0c-176a-dc11-c535-47d023f237a8@suse.cz> From: Prakash Gupta Message-ID: Date: Fri, 1 Sep 2017 10:30:23 +0530 MIME-Version: 1.0 In-Reply-To: <82346e0c-176a-dc11-c535-47d023f237a8@suse.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka , akpm@linux-foundation.org, mhocko@suse.com, will.deacon@arm.com, catalin.marinas@arm.com, iamjoonsoo.kim@lge.com, rmk+kernel@arm.linux.org.uk, linux-kernel@vger.kernel.org, linux-mm@kvack.org On 8/31/2017 1:04 PM, Vlastimil Babka wrote: > On 08/30/2017 09:32 AM, Prakash Gupta wrote: >> The page_owner stacktrace always begin as follows: >> >> [] save_stack+0x40/0xc8 >> [] __set_page_owner+0x3c/0x6c > > Hmm, on x86_64 it looks like this: > > save_stack_trace+0x16/0x20 > save_stack+0x43/0xe0 > __set_page_owner+0x24/0x50 > > So after your patch there's still __set_page_owner. Seems x86 needs > something similar to your arm64 patch 1/2? Yes, that's correct. > >> These two entries do not provide any useful information and limits the >> available stacktrace depth. The page_owner stacktrace was skipping caller >> function from stack entries but this was missed with commit f2ca0b557107 >> ("mm/page_owner: use stackdepot to store stacktrace") >> >> Example page_owner entry after the patch: >> >> Page allocated via order 0, mask 0x8(ffffff80085fb714) >> PFN 654411 type Movable Block 639 type CMA Flags 0x0(ffffffbe5c7f12c0) >> [] post_alloc_hook+0x70/0x80 >> ... >> [] msm_comm_try_state+0x5f8/0x14f4 >> [] msm_vidc_open+0x5e4/0x7d0 >> [] msm_v4l2_open+0xa8/0x224 >> >> Fixes: f2ca0b557107 ("mm/page_owner: use stackdepot to store stacktrace") >> Signed-off-by: Prakash Gupta > > The patch itself improves the output regardless of whether we fix the > x86 internals, so: > > Acked-by: Vlastimil Babka Thanks. > >> --- >> mm/page_owner.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/mm/page_owner.c b/mm/page_owner.c >> index 10d16fc45bd9..75b7c39bf1df 100644 >> --- a/mm/page_owner.c >> +++ b/mm/page_owner.c >> @@ -139,7 +139,7 @@ static noinline depot_stack_handle_t save_stack(gfp_t flags) >> .nr_entries = 0, >> .entries = entries, >> .max_entries = PAGE_OWNER_STACK_DEPTH, >> - .skip = 0 >> + .skip = 2 >> }; >> depot_stack_handle_t handle; >> >> > -- 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