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From: Mel Gorman <mgorman@suse.de>
To: Michal Hocko <mhocko@kernel.org>
Cc: David Rientjes <rientjes@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Andrea Argangeli <andrea@kernel.org>,
	Zi Yan <zi.yan@cs.rutgers.edu>,
	Stefan Priebe - Profihost AG <s.priebe@profihost.ag>,
	"Kirill A. Shutemov" <kirill@shutemov.name>,
	linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
	Stable tree <stable@vger.kernel.org>
Subject: Re: [PATCH 1/2] mm: thp:  relax __GFP_THISNODE for MADV_HUGEPAGE mappings
Date: Tue, 9 Oct 2018 14:00:34 +0100
Message-ID: <20181009130034.GD6931@suse.de> (raw)
In-Reply-To: <20181009122745.GN8528@dhcp22.suse.cz>

On Tue, Oct 09, 2018 at 02:27:45PM +0200, Michal Hocko wrote:
> [Sorry for being slow in responding but I was mostly offline last few
>  days]
> 
> On Tue 09-10-18 10:48:25, Mel Gorman wrote:
> [...]
> > This goes back to my point that the MADV_HUGEPAGE hint should not make
> > promises about locality and that introducing MADV_LOCAL for specialised
> > libraries may be more appropriate with the initial semantic being how it
> > treats MADV_HUGEPAGE regions.
> 
> I agree with your other points and not going to repeat them. I am not
> sure madvise s the best API for the purpose though. We are talking about
> memory policy here and there is an existing api for that so I would
> _prefer_ to reuse it for this purpose.
> 

I flip-flopped on that one in my head multiple times on the basis of
how strict it should be. Memory policies tend to be black or white --
bind here, interleave there, etc. It wasn't clear to me what the best
policy would be to describe "allocate local as best as you can but allow
fallbacks if necessary". Hence, I started leaning towards advise as it is
really about advice that the kernel can ignore if necessary. That said,
I don't feel as strongly about the "how" as I do about the fact that
applications and libraries should not depend on side-effects of the
MADV_HUGEPAGE implementation that relate to locality.

-- 
Mel Gorman
SUSE Labs

  reply index

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 [this message]
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
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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