From: Vlastimil Babka <vbabka@suse.cz>
To: Michal Hocko <mhocko@kernel.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>,
David Rientjes <rientjes@google.com>,
Andrea Argangeli <andrea@kernel.org>,
Zi Yan <zi.yan@cs.rutgers.edu>,
Stefan Priebe - Profihost AG <s.priebe@profihost.ag>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask
Date: Mon, 22 Oct 2018 15:35:24 +0200 [thread overview]
Message-ID: <18476b0b-7300-f340-5845-9de0a019c65c@suse.cz> (raw)
In-Reply-To: <20181022133058.GE18839@dhcp22.suse.cz>
On 10/22/18 3:30 PM, Michal Hocko wrote:
> On Mon 22-10-18 15:15:38, Vlastimil Babka wrote:
>>> Forgot to add. One notable exception would be that the previous code
>>> would allow to hit
>>> WARN_ON_ONCE(policy->mode == MPOL_BIND && (gfp & __GFP_THISNODE));
>>> in policy_node if the requested node (e.g. cpu local one) was outside of
>>> the mbind nodemask. This is not possible now. We haven't heard about any
>>> such warning yet so it is unlikely that it happens though.
>>
>> I don't think the previous code could hit the warning, as the hugepage
>> path that would add __GFP_THISNODE didn't call policy_node() (containing
>> the warning) at all. IIRC early of your patch did hit the warning
>> though, which is why you added the MPOL_BIND policy check.
>
> Are you sure? What prevents node_isset(node, policy_nodemask()) == F and
> fallback to the !huge allocation path?
That can indeed happen, but then the code also skipped the "gfp |=
__GFP_THISNODE" part, right? So the warning wouldn't trigger.
> alloc_pages_vma is usually called
> with the local node and processes shouldn't run off their bounded num
> mask but is that guaranteed? Moreover do_huge_pmd_wp_page_fallback uses
> the former numa binding and that might be outside of the policy mask.
>
> In any case, as I've said this is highly unlikely to hit which is
> underlined by the lack of reports.
>
next prev parent reply other threads:[~2018-10-22 13:35 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 12:03 [PATCH 0/2] thp nodereclaim fixes Michal Hocko
2018-09-25 12:03 ` [PATCH 1/2] mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings Michal Hocko
2018-09-25 12:20 ` Mel Gorman
2018-09-25 12:30 ` Michal Hocko
2018-10-04 20:16 ` David Rientjes
2018-10-04 21:10 ` Andrea Arcangeli
2018-10-04 23:05 ` David Rientjes
2018-10-06 3:19 ` Andrea Arcangeli
2018-10-05 7:38 ` Mel Gorman
2018-10-05 20:35 ` David Rientjes
2018-10-05 23:21 ` Andrea Arcangeli
2018-10-08 20:41 ` David Rientjes
2018-10-09 9:48 ` Mel Gorman
2018-10-09 12:27 ` Michal Hocko
2018-10-09 13:00 ` Mel Gorman
2018-10-09 14:25 ` Michal Hocko
2018-10-09 15:16 ` Mel Gorman
2018-10-09 23:03 ` Andrea Arcangeli
2018-10-10 21:19 ` David Rientjes
2018-10-15 22:30 ` David Rientjes
2018-10-15 22:44 ` Andrew Morton
2018-10-15 23:19 ` Andrea Arcangeli
2018-10-22 20:54 ` David Rientjes
2018-10-16 7:46 ` Mel Gorman
2018-10-16 22:37 ` Andrew Morton
2018-10-16 23:11 ` Andrea Arcangeli
2018-10-16 23:16 ` Andrew Morton
2018-10-17 7:08 ` Michal Hocko
2018-10-17 9:00 ` Mel Gorman
2018-10-22 21:04 ` David Rientjes
2018-10-23 1:27 ` Zi Yan
2018-10-28 21:45 ` David Rientjes
2018-10-23 7:57 ` Mel Gorman
2018-10-23 8:38 ` Mel Gorman
2018-10-15 22:57 ` Andrea Arcangeli
2018-10-22 20:45 ` David Rientjes
2018-10-09 22:17 ` David Rientjes
2018-10-09 22:51 ` Andrea Arcangeli
2018-10-10 7:54 ` Vlastimil Babka
2018-10-10 21:00 ` David Rientjes
2018-10-09 13:08 ` Vlastimil Babka
2018-10-09 22:21 ` Andrea Arcangeli
2018-10-29 5:17 ` Balbir Singh
2018-10-29 9:00 ` Michal Hocko
2018-10-29 9:42 ` Balbir Singh
2018-10-29 10:08 ` Michal Hocko
2018-10-29 10:56 ` Andrea Arcangeli
2018-09-25 12:03 ` [PATCH 2/2] mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask Michal Hocko
2018-09-26 13:30 ` Kirill A. Shutemov
2018-09-26 14:17 ` Michal Hocko
2018-09-26 14:22 ` Michal Hocko
2018-10-19 2:11 ` Andrew Morton
2018-10-19 8:06 ` Michal Hocko
2018-10-22 13:27 ` Vlastimil Babka
2018-10-24 23:17 ` Andrew Morton
2018-10-25 4:56 ` Vlastimil Babka
2018-10-25 16:14 ` Michal Hocko
2018-10-25 16:18 ` Andrew Morton
2018-10-25 16:45 ` Michal Hocko
2018-10-22 13:15 ` Vlastimil Babka
2018-10-22 13:30 ` Michal Hocko
2018-10-22 13:35 ` Vlastimil Babka [this message]
2018-10-22 13:46 ` Michal Hocko
2018-10-22 13:53 ` Vlastimil Babka
2018-10-04 20:17 ` David Rientjes
2018-10-04 21:49 ` Zi Yan
2018-10-09 12:36 ` Michal Hocko
2018-09-26 13:08 ` linux-mm@ archive on lore.kernel.org (Was: [PATCH 0/2] thp nodereclaim fixes) Kirill A. Shutemov
2018-09-26 13:14 ` Michal Hocko
2018-09-26 22:22 ` Andrew Morton
2018-09-26 23:08 ` Mel Gorman
2018-09-27 0:47 ` Konstantin Ryabitsev
2018-09-26 15:25 ` Konstantin Ryabitsev
2018-09-27 11:30 ` Kirill A. Shutemov
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