From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id 85F8A8E0001 for ; Tue, 18 Dec 2018 06:28:25 -0500 (EST) Received: by mail-ed1-f69.google.com with SMTP id 39so3573091edq.13 for ; Tue, 18 Dec 2018 03:28:25 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id y33si1115537eda.109.2018.12.18.03.28.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Dec 2018 03:28:24 -0800 (PST) Date: Tue, 18 Dec 2018 12:28:22 +0100 From: Michal Hocko Subject: Re: [PATCH] mm: do not report isolation failures for CMA pages Message-ID: <20181218112822.GG30879@dhcp22.suse.cz> References: <20181218092802.31429-1-mhocko@kernel.org> <20181218101831.ma3j5llxcsthibop@d104.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181218101831.ma3j5llxcsthibop@d104.suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Oscar Salvador Cc: Andrew Morton , Oscar Salvador , Anshuman Khandual , Heiko Carstens , linux-mm@kvack.org, LKML On Tue 18-12-18 11:18:35, Oscar Salvador wrote: > On Tue, Dec 18, 2018 at 10:28:02AM +0100, Michal Hocko wrote: > > From: Michal Hocko > > > > Heiko has complained that his log is swamped by warnings from has_unmovable_pages > > [ 20.536664] page dumped because: has_unmovable_pages > > [ 20.536792] page:000003d081ff4080 count:1 mapcount:0 mapping:000000008ff88600 index:0x0 compound_mapcount: 0 > > [ 20.536794] flags: 0x3fffe0000010200(slab|head) > > [ 20.536795] raw: 03fffe0000010200 0000000000000100 0000000000000200 000000008ff88600 > > [ 20.536796] raw: 0000000000000000 0020004100000000 ffffffff00000001 0000000000000000 > > [ 20.536797] page dumped because: has_unmovable_pages > > [ 20.536814] page:000003d0823b0000 count:1 mapcount:0 mapping:0000000000000000 index:0x0 > > [ 20.536815] flags: 0x7fffe0000000000() > > [ 20.536817] raw: 07fffe0000000000 0000000000000100 0000000000000200 0000000000000000 > > [ 20.536818] raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000 > > > > which are not triggered by the memory hotplug but rather CMA allocator. > > The original idea behind dumping the page state for all call paths was > > that these messages will be helpful debugging failures. From the above > > it seems that this is not the case for the CMA path because we are > > lacking much more context. E.g the second reported page might be a CMA > > allocated page. It is still interesting to see a slab page in the CMA > > area but it is hard to tell whether this is bug from the above output > > alone. > > > > Address this issue by dumping the page state only on request. Both > > start_isolate_page_range and has_unmovable_pages already have an > > argument to ignore hwpoison pages so make this argument more generic and > > turn it into flags and allow callers to combine non-default modes into a > > mask. While we are at it, has_unmovable_pages call from is_pageblock_removable_nolock > > (sysfs removable file) is questionable to report the failure so drop it > > from there as well. > > > > Reported-by: Heiko Carstens > > Signed-off-by: Michal Hocko > > Looks good to me, and it makes sense to not spam other users. > > Just one thing: > > AFAICS alloc_contig_range() can also be called from hugetlb code. > Do we weant to specify that in the changelog too? > And possibly change the patch title to: Well, I haven't seen any reports about hugetlb pages so I didn't bother to mention it. Is this really important to note? > "Only report isolation failures from memhotplug code" ? only report isolation failures when offlining memory > Although is_pageblock_removable_nolock will not report the failures > now, so I am not sure. > > Reviewed-by: Oscar Salvador Thanks! -- Michal Hocko SUSE Labs