From: David Rientjes <rientjes@google.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
mgorman@techsingularity.net, Vlastimil Babka <vbabka@suse.cz>,
ying.huang@intel.com, s.priebe@profihost.ag,
Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
alex.williamson@redhat.com, lkp@01.org, kirill@shutemov.name,
Andrew Morton <akpm@linux-foundation.org>,
zi.yan@cs.rutgers.edu
Subject: Re: MADV_HUGEPAGE vs. NUMA semantic (was: Re: [LKP] [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression)
Date: Thu, 6 Dec 2018 15:49:04 -0800 (PST) [thread overview]
Message-ID: <alpine.DEB.2.21.1812061544360.162675@chino.kir.corp.google.com> (raw)
In-Reply-To: <20181206091405.GD1286@dhcp22.suse.cz>
On Thu, 6 Dec 2018, Michal Hocko wrote:
> MADV_HUGEPAGE changes the picture because the caller expressed a need
> for THP and is willing to go extra mile to get it. That involves
> allocation latency and as of now also a potential remote access. We do
> not have complete agreement on the later but the prevailing argument is
> that any strong NUMA locality is just reinventing node-reclaim story
> again or makes THP success rate down the toilet (to quote Mel). I agree
> that we do not want to fallback to a remote node overeagerly. I believe
> that something like the below would be sensible
> 1) THP on a local node with compaction not giving up too early
> 2) THP on a remote node in NOWAIT mode - so no direct
> compaction/reclaim (trigger kswapd/kcompactd only for
> defrag=defer+madvise)
> 3) fallback to the base page allocation
>
I disagree that MADV_HUGEPAGE should take on any new semantic that
overrides the preference of node local memory for a hugepage, which is the
nearly four year behavior. The order of MADV_HUGEPAGE preferences listed
above would cause current users to regress who rely on local small page
fallback rather than remote hugepages because the access latency is much
better. I think the preference of remote hugepages over local small pages
needs to be expressed differently to prevent regression.
next prev parent reply other threads:[~2018-12-06 23:49 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-27 6:25 [LKP] [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression kernel test robot
2018-11-27 17:08 ` Linus Torvalds
2018-11-27 18:17 ` Michal Hocko
2018-11-27 18:21 ` Michal Hocko
2018-11-27 19:05 ` Vlastimil Babka
2018-11-27 19:16 ` Vlastimil Babka
2018-11-27 20:57 ` Andrea Arcangeli
2018-11-27 22:50 ` Linus Torvalds
2018-11-28 6:30 ` Michal Hocko
2018-11-28 3:20 ` Huang, Ying
2018-11-28 16:48 ` Linus Torvalds
2018-11-28 18:39 ` Andrea Arcangeli
2018-11-28 23:10 ` David Rientjes
2018-12-03 18:01 ` Linus Torvalds
2018-12-03 18:14 ` Michal Hocko
2018-12-03 18:19 ` Linus Torvalds
2018-12-03 18:30 ` Michal Hocko
2018-12-03 18:45 ` Linus Torvalds
2018-12-03 18:59 ` Michal Hocko
2018-12-03 19:23 ` Andrea Arcangeli
2018-12-03 20:26 ` David Rientjes
2018-12-03 19:28 ` Linus Torvalds
2018-12-03 20:12 ` Andrea Arcangeli
2018-12-03 20:36 ` David Rientjes
2018-12-03 22:04 ` Linus Torvalds
2018-12-03 22:27 ` Linus Torvalds
2018-12-03 22:57 ` David Rientjes
2018-12-04 9:22 ` Vlastimil Babka
2018-12-04 10:45 ` Mel Gorman
2018-12-05 0:47 ` David Rientjes
2018-12-05 9:08 ` Michal Hocko
2018-12-05 10:43 ` Mel Gorman
2018-12-05 11:43 ` Michal Hocko
2018-12-05 10:06 ` Mel Gorman
2018-12-05 20:40 ` Andrea Arcangeli
2018-12-05 21:59 ` David Rientjes
2018-12-06 0:00 ` Andrea Arcangeli
2018-12-05 22:03 ` Linus Torvalds
2018-12-05 22:12 ` David Rientjes
2018-12-05 23:36 ` Andrea Arcangeli
2018-12-05 23:51 ` Linus Torvalds
2018-12-06 0:58 ` Linus Torvalds
2018-12-06 9:14 ` MADV_HUGEPAGE vs. NUMA semantic (was: Re: [LKP] [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression) Michal Hocko
2018-12-06 23:49 ` David Rientjes [this message]
2018-12-07 7:34 ` Michal Hocko
2018-12-07 4:31 ` Linus Torvalds
2018-12-07 7:49 ` Michal Hocko
2018-12-07 9:06 ` Vlastimil Babka
2018-12-07 23:15 ` David Rientjes
2018-12-06 23:43 ` [LKP] [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression David Rientjes
2018-12-07 4:01 ` Linus Torvalds
2018-12-10 0:29 ` David Rientjes
2018-12-10 4:49 ` Andrea Arcangeli
2018-12-12 0:37 ` David Rientjes
2018-12-12 9:50 ` Michal Hocko
2018-12-12 17:00 ` Andrea Arcangeli
2018-12-14 11:32 ` Michal Hocko
2018-12-12 10:14 ` Vlastimil Babka
2018-12-14 21:04 ` David Rientjes
2018-12-14 21:33 ` Vlastimil Babka
2018-12-21 22:18 ` David Rientjes
2018-12-22 12:08 ` Mel Gorman
2018-12-14 23:11 ` Mel Gorman
2018-12-21 22:15 ` David Rientjes
2018-12-12 10:44 ` Andrea Arcangeli
2019-04-15 11:48 ` Michal Hocko
2018-12-06 0:18 ` David Rientjes
2018-12-06 0:54 ` Andrea Arcangeli
2018-12-06 9:23 ` Vlastimil Babka
2018-12-03 20:39 ` David Rientjes
2018-12-03 21:25 ` Michal Hocko
2018-12-03 21:53 ` David Rientjes
2018-12-04 8:48 ` Michal Hocko
2018-12-05 0:07 ` David Rientjes
2018-12-05 10:18 ` Michal Hocko
2018-12-05 19:16 ` David Rientjes
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