From: David Rientjes <rientjes@google.com> To: Mel Gorman <mgorman@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>, Vlastimil Babka <vbabka@suse.cz>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Greg Thelen <gthelen@google.com>, Hugh Dickins <hughd@google.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [patch v2 4/4] mm, thp: do not perform sync compaction on pagefault Date: Fri, 2 May 2014 13:29:33 -0700 (PDT) [thread overview] Message-ID: <alpine.DEB.2.02.1405021319350.24195@chino.kir.corp.google.com> (raw) In-Reply-To: <20140502115834.GR23991@suse.de> On Fri, 2 May 2014, Mel Gorman wrote: > > The page locks I'm referring to is the lock_page() in __unmap_and_move() > > that gets called for sync compaction after the migrate_pages() iteration > > makes a few passes and unsuccessfully grabs it. This becomes a forced > > migration since __unmap_and_move() returns -EAGAIN when the trylock fails. > > > > Can that be fixed then instead of disabling it entirely? > We could return -EAGAIN when the trylock_page() fails for MIGRATE_SYNC_LIGHT. It would become a forced migration but we ignore that currently for MIGRATE_ASYNC, and I could extend it to be ignored for MIGRATE_SYNC_LIGHT as well. > > We have perf profiles from one workload in particular that shows > > contention on i_mmap_mutex (anon isn't interesting since the vast majority > > of memory on this workload [120GB on a 128GB machine] is has a gup pin and > > doesn't get isolated because of 119d6d59dcc0 ("mm, compaction: avoid > > isolating pinned pages")) between cpus all doing memory compaction trying > > to fault thp memory. > > > > Abort SYNC_LIGHT compaction if the mutex is contended. > Yeah, I have patches for that as well but we're waiting to see if they are actually needed when sync compaction is disabled for thp. If we aren't actually going to disable it entirely, then I can revive those patches if the contention becomes such an issue. > > That's one example that we've seen, but the fact remains that at times > > sync compaction will iterate the entire 128GB machine and not allow an > > order-9 page to be allocated and there's nothing to preempt it like the > > need_resched() or lock contention checks that async compaction has. > > Make compact_control->sync the same enum field and check for contention > on the async/sync_light case but leave it for sync if compacting via the > proc interface? > Ok, that certainly can be done, I wasn't sure you would be happy with such a change. I'm not sure there's so much of a difference between the new compact_control->sync == MIGRATE_ASYNC and == MIGRATE_SYNC_LIGHT now, though. Would it make sense to remove MIGRATE_SYNC_LIGHT entirely from the page allocator, i.e. remove sync_migration entirely, and just retry with a second call to compaction before failing instead?
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From: David Rientjes <rientjes@google.com> To: Mel Gorman <mgorman@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org>, Rik van Riel <riel@redhat.com>, Vlastimil Babka <vbabka@suse.cz>, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Greg Thelen <gthelen@google.com>, Hugh Dickins <hughd@google.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [patch v2 4/4] mm, thp: do not perform sync compaction on pagefault Date: Fri, 2 May 2014 13:29:33 -0700 (PDT) [thread overview] Message-ID: <alpine.DEB.2.02.1405021319350.24195@chino.kir.corp.google.com> (raw) In-Reply-To: <20140502115834.GR23991@suse.de> On Fri, 2 May 2014, Mel Gorman wrote: > > The page locks I'm referring to is the lock_page() in __unmap_and_move() > > that gets called for sync compaction after the migrate_pages() iteration > > makes a few passes and unsuccessfully grabs it. This becomes a forced > > migration since __unmap_and_move() returns -EAGAIN when the trylock fails. > > > > Can that be fixed then instead of disabling it entirely? > We could return -EAGAIN when the trylock_page() fails for MIGRATE_SYNC_LIGHT. It would become a forced migration but we ignore that currently for MIGRATE_ASYNC, and I could extend it to be ignored for MIGRATE_SYNC_LIGHT as well. > > We have perf profiles from one workload in particular that shows > > contention on i_mmap_mutex (anon isn't interesting since the vast majority > > of memory on this workload [120GB on a 128GB machine] is has a gup pin and > > doesn't get isolated because of 119d6d59dcc0 ("mm, compaction: avoid > > isolating pinned pages")) between cpus all doing memory compaction trying > > to fault thp memory. > > > > Abort SYNC_LIGHT compaction if the mutex is contended. > Yeah, I have patches for that as well but we're waiting to see if they are actually needed when sync compaction is disabled for thp. If we aren't actually going to disable it entirely, then I can revive those patches if the contention becomes such an issue. > > That's one example that we've seen, but the fact remains that at times > > sync compaction will iterate the entire 128GB machine and not allow an > > order-9 page to be allocated and there's nothing to preempt it like the > > need_resched() or lock contention checks that async compaction has. > > Make compact_control->sync the same enum field and check for contention > on the async/sync_light case but leave it for sync if compacting via the > proc interface? > Ok, that certainly can be done, I wasn't sure you would be happy with such a change. I'm not sure there's so much of a difference between the new compact_control->sync == MIGRATE_ASYNC and == MIGRATE_SYNC_LIGHT now, though. Would it make sense to remove MIGRATE_SYNC_LIGHT entirely from the page allocator, i.e. remove sync_migration entirely, and just retry with a second call to compaction before failing instead? -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2014-05-02 20:29 UTC|newest] Thread overview: 267+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-05-01 0:45 [patch 1/2] mm, migration: add destination page freeing callback David Rientjes 2014-05-01 0:45 ` David Rientjes 2014-05-01 0:45 ` [patch 2/2] mm, compaction: return failed migration target pages back to freelist David Rientjes 2014-05-01 0:45 ` David Rientjes 2014-05-01 5:10 ` Naoya Horiguchi 2014-05-01 21:02 ` David Rientjes 2014-05-01 21:02 ` David Rientjes 2014-05-01 5:08 ` [patch 1/2] mm, migration: add destination page freeing callback Naoya Horiguchi [not found] ` <5361d71e.236ec20a.1b3d.ffffc8aeSMTPIN_ADDED_BROKEN@mx.google.com> 2014-05-01 21:02 ` David Rientjes 2014-05-01 21:02 ` David Rientjes 2014-05-01 21:35 ` [patch v2 1/4] " David Rientjes 2014-05-01 21:35 ` David Rientjes 2014-05-01 21:35 ` [patch v2 2/4] mm, compaction: return failed migration target pages back to freelist David Rientjes 2014-05-01 21:35 ` David Rientjes 2014-05-02 10:11 ` Mel Gorman 2014-05-02 10:11 ` Mel Gorman 2014-05-02 15:23 ` Vlastimil Babka 2014-05-02 15:23 ` Vlastimil Babka 2014-05-02 15:26 ` [PATCH] mm/compaction: do not count migratepages when unnecessary Vlastimil Babka 2014-05-06 21:18 ` Naoya Horiguchi [not found] ` <1399411134-k43fsr0p@n-horiguchi@ah.jp.nec.com> 2014-05-07 9:33 ` Vlastimil Babka 2014-05-07 9:33 ` Vlastimil Babka 2014-05-02 15:27 ` [PATCH 2/2] mm/compaction: avoid rescanning pageblocks in isolate_freepages Vlastimil Babka 2014-05-02 15:27 ` Vlastimil Babka 2014-05-06 22:19 ` Naoya Horiguchi [not found] ` <1399414778-xakujfb3@n-horiguchi@ah.jp.nec.com> 2014-05-07 9:22 ` Vlastimil Babka 2014-05-07 9:22 ` Vlastimil Babka 2014-05-02 15:29 ` [PATCH 1/2] mm/compaction: do not count migratepages when unnecessary Vlastimil Babka 2014-05-02 15:29 ` Vlastimil Babka 2014-05-01 21:35 ` [patch v2 3/4] mm, compaction: add per-zone migration pfn cache for async compaction David Rientjes 2014-05-01 21:35 ` David Rientjes 2014-05-05 9:34 ` Vlastimil Babka 2014-05-05 9:34 ` Vlastimil Babka 2014-05-05 9:51 ` David Rientjes 2014-05-05 9:51 ` David Rientjes 2014-05-05 14:24 ` Vlastimil Babka 2014-05-05 14:24 ` Vlastimil Babka 2014-05-06 0:29 ` David Rientjes 2014-05-06 0:29 ` David Rientjes 2014-05-06 11:52 ` Vlastimil Babka 2014-05-06 11:52 ` Vlastimil Babka 2014-05-01 21:35 ` [patch v2 4/4] mm, thp: do not perform sync compaction on pagefault David Rientjes 2014-05-01 21:35 ` David Rientjes 2014-05-02 10:22 ` Mel Gorman 2014-05-02 10:22 ` Mel Gorman 2014-05-02 11:22 ` David Rientjes 2014-05-02 11:22 ` David Rientjes 2014-05-02 11:58 ` Mel Gorman 2014-05-02 20:29 ` David Rientjes [this message] 2014-05-02 20:29 ` David Rientjes 2014-05-05 14:48 ` Vlastimil Babka 2014-05-05 14:48 ` Vlastimil Babka 2014-05-06 8:55 ` Mel Gorman 2014-05-06 8:55 ` Mel Gorman 2014-05-06 15:05 ` Vlastimil Babka 2014-05-06 15:05 ` Vlastimil Babka 2014-05-02 10:10 ` [patch v2 1/4] mm, migration: add destination page freeing callback Mel Gorman 2014-05-07 2:22 ` [patch v3 1/6] " David Rientjes 2014-05-07 2:22 ` David Rientjes 2014-05-07 2:22 ` [patch v3 2/6] mm, compaction: return failed migration target pages back to freelist David Rientjes 2014-05-07 2:22 ` David Rientjes 2014-05-07 14:14 ` Naoya Horiguchi 2014-05-07 21:15 ` Andrew Morton 2014-05-07 21:15 ` Andrew Morton 2014-05-07 21:21 ` David Rientjes 2014-05-07 21:21 ` David Rientjes 2014-05-12 8:35 ` Vlastimil Babka 2014-05-12 8:35 ` Vlastimil Babka 2014-05-07 21:39 ` Greg Thelen 2014-05-07 21:39 ` Greg Thelen 2014-05-12 8:37 ` Vlastimil Babka 2014-05-12 8:37 ` Vlastimil Babka 2014-05-07 2:22 ` [patch v3 3/6] mm, compaction: add per-zone migration pfn cache for async compaction David Rientjes 2014-05-07 2:22 ` David Rientjes 2014-05-07 9:34 ` Vlastimil Babka 2014-05-07 9:34 ` Vlastimil Babka 2014-05-07 20:56 ` Naoya Horiguchi 2014-05-07 2:22 ` [patch v3 4/6] mm, compaction: embed migration mode in compact_control David Rientjes 2014-05-07 2:22 ` David Rientjes 2014-05-07 9:55 ` Vlastimil Babka 2014-05-07 9:55 ` Vlastimil Babka 2014-05-07 10:36 ` [patch v4 " David Rientjes 2014-05-07 10:36 ` David Rientjes 2014-05-09 22:03 ` Andrew Morton 2014-05-09 22:03 ` Andrew Morton 2014-05-07 2:22 ` [patch v3 5/6] mm, thp: avoid excessive compaction latency during fault David Rientjes 2014-05-07 2:22 ` David Rientjes 2014-05-07 9:39 ` Mel Gorman 2014-05-07 9:39 ` Mel Gorman 2014-05-08 5:30 ` [patch -mm] mm, thp: avoid excessive compaction latency during fault fix David Rientjes 2014-05-08 5:30 ` David Rientjes 2014-05-13 10:00 ` Vlastimil Babka 2014-05-13 10:00 ` Vlastimil Babka 2014-05-22 2:49 ` David Rientjes 2014-05-22 2:49 ` David Rientjes 2014-05-22 8:43 ` Vlastimil Babka 2014-05-22 8:43 ` Vlastimil Babka 2014-05-07 2:22 ` [patch v3 6/6] mm, compaction: terminate async compaction when rescheduling David Rientjes 2014-05-07 2:22 ` David Rientjes 2014-05-07 9:41 ` Mel Gorman 2014-05-07 9:41 ` Mel Gorman 2014-05-07 12:09 ` [PATCH v2 1/2] mm/compaction: do not count migratepages when unnecessary Vlastimil Babka 2014-05-07 12:09 ` Vlastimil Babka 2014-05-07 12:09 ` [PATCH v2 2/2] mm/compaction: avoid rescanning pageblocks in isolate_freepages Vlastimil Babka 2014-05-07 12:09 ` Vlastimil Babka 2014-05-07 21:47 ` David Rientjes 2014-05-07 21:47 ` David Rientjes 2014-05-07 22:06 ` Naoya Horiguchi 2014-05-08 5:28 ` Joonsoo Kim 2014-05-08 5:28 ` Joonsoo Kim 2014-05-12 9:09 ` Vlastimil Babka 2014-05-12 9:09 ` Vlastimil Babka 2014-05-13 1:15 ` Joonsoo Kim 2014-05-13 1:15 ` Joonsoo Kim 2014-05-09 15:49 ` Michal Nazarewicz 2014-05-09 15:49 ` Michal Nazarewicz 2014-05-19 10:14 ` Vlastimil Babka 2014-05-19 10:14 ` Vlastimil Babka 2014-05-22 2:51 ` David Rientjes 2014-05-22 2:51 ` David Rientjes 2014-05-07 21:44 ` [PATCH v2 1/2] mm/compaction: do not count migratepages when unnecessary David Rientjes 2014-05-07 21:44 ` David Rientjes 2014-05-09 15:48 ` Michal Nazarewicz 2014-05-09 15:48 ` Michal Nazarewicz 2014-05-12 9:51 ` Vlastimil Babka 2014-05-12 9:51 ` Vlastimil Babka 2014-05-07 12:10 ` [patch v3 6/6] mm, compaction: terminate async compaction when rescheduling Vlastimil Babka 2014-05-07 12:10 ` Vlastimil Babka 2014-05-07 21:20 ` Andrew Morton 2014-05-07 21:20 ` Andrew Morton 2014-05-07 21:28 ` David Rientjes 2014-05-07 21:28 ` David Rientjes 2014-05-08 5:17 ` Joonsoo Kim 2014-05-08 5:17 ` Joonsoo Kim 2014-05-12 14:15 ` [PATCH] mm, compaction: properly signal and act upon lock and need_sched() contention Vlastimil Babka 2014-05-12 14:15 ` Vlastimil Babka 2014-05-12 15:34 ` Naoya Horiguchi [not found] ` <1399908847-ouuxeneo@n-horiguchi@ah.jp.nec.com> 2014-05-12 15:45 ` Vlastimil Babka 2014-05-12 15:45 ` Vlastimil Babka 2014-05-12 15:53 ` Naoya Horiguchi 2014-05-12 20:28 ` David Rientjes 2014-05-12 20:28 ` David Rientjes 2014-05-13 8:50 ` Vlastimil Babka 2014-05-13 8:50 ` Vlastimil Babka 2014-05-13 0:44 ` Joonsoo Kim 2014-05-13 0:44 ` Joonsoo Kim 2014-05-13 8:54 ` Vlastimil Babka 2014-05-13 8:54 ` Vlastimil Babka 2014-05-15 2:21 ` Joonsoo Kim 2014-05-15 2:21 ` Joonsoo Kim 2014-05-16 9:47 ` [PATCH v2] " Vlastimil Babka 2014-05-16 9:47 ` Vlastimil Babka 2014-05-16 17:33 ` Michal Nazarewicz 2014-05-16 17:33 ` Michal Nazarewicz 2014-05-19 23:37 ` Andrew Morton 2014-05-19 23:37 ` Andrew Morton 2014-05-21 14:13 ` Vlastimil Babka 2014-05-21 14:13 ` Vlastimil Babka 2014-05-21 20:11 ` Andrew Morton 2014-05-21 20:11 ` Andrew Morton 2014-05-22 3:20 ` compaction is still too expensive for thp (was: [PATCH v2] mm, compaction: properly signal and act upon lock and need_sched() contention) David Rientjes 2014-05-22 3:20 ` David Rientjes 2014-05-22 8:10 ` compaction is still too expensive for thp Vlastimil Babka 2014-05-22 8:10 ` Vlastimil Babka 2014-05-22 8:55 ` David Rientjes 2014-05-22 8:55 ` David Rientjes 2014-05-22 12:03 ` Vlastimil Babka 2014-05-22 12:03 ` Vlastimil Babka 2014-06-04 0:29 ` [patch -mm 1/3] mm: rename allocflags_to_migratetype for clarity David Rientjes 2014-06-04 0:29 ` David Rientjes 2014-06-04 0:29 ` [patch -mm 2/3] mm, compaction: pass gfp mask to compact_control David Rientjes 2014-06-04 0:29 ` David Rientjes 2014-06-04 0:30 ` [patch -mm 3/3] mm, compaction: avoid compacting memory for thp if pageblock cannot become free David Rientjes 2014-06-04 0:30 ` David Rientjes 2014-06-04 11:04 ` Mel Gorman 2014-06-04 11:04 ` Mel Gorman 2014-06-04 22:02 ` David Rientjes 2014-06-04 22:02 ` David Rientjes 2014-06-04 16:07 ` Vlastimil Babka 2014-06-04 16:07 ` Vlastimil Babka 2014-06-04 16:11 ` [RFC PATCH 1/6] mm, compaction: periodically drop lock and restore IRQs in scanners Vlastimil Babka 2014-06-04 16:11 ` Vlastimil Babka 2014-06-04 16:11 ` [RFC PATCH 2/6] mm, compaction: skip rechecks when lock was already held Vlastimil Babka 2014-06-04 16:11 ` Vlastimil Babka 2014-06-04 23:46 ` David Rientjes 2014-06-04 23:46 ` David Rientjes 2014-06-04 16:11 ` [RFC PATCH 3/6] mm, compaction: remember position within pageblock in free pages scanner Vlastimil Babka 2014-06-04 16:11 ` Vlastimil Babka 2014-06-04 16:11 ` [RFC PATCH 4/6] mm, compaction: skip buddy pages by their order in the migrate scanner Vlastimil Babka 2014-06-04 16:11 ` Vlastimil Babka 2014-06-05 0:02 ` David Rientjes 2014-06-05 0:02 ` David Rientjes 2014-06-05 9:24 ` Vlastimil Babka 2014-06-05 9:24 ` Vlastimil Babka 2014-06-05 21:30 ` David Rientjes 2014-06-05 21:30 ` David Rientjes 2014-06-06 7:20 ` Vlastimil Babka 2014-06-06 7:20 ` Vlastimil Babka 2014-06-09 9:09 ` David Rientjes 2014-06-09 9:09 ` David Rientjes 2014-06-09 11:35 ` Vlastimil Babka 2014-06-09 11:35 ` Vlastimil Babka 2014-06-09 22:25 ` David Rientjes 2014-06-09 22:25 ` David Rientjes 2014-06-10 7:26 ` Vlastimil Babka 2014-06-10 7:26 ` Vlastimil Babka 2014-06-10 23:54 ` David Rientjes 2014-06-10 23:54 ` David Rientjes 2014-06-11 12:18 ` Vlastimil Babka 2014-06-11 12:18 ` Vlastimil Babka 2014-06-12 0:21 ` David Rientjes 2014-06-12 0:21 ` David Rientjes 2014-06-12 11:56 ` Vlastimil Babka 2014-06-12 11:56 ` Vlastimil Babka 2014-06-12 21:48 ` David Rientjes 2014-06-12 21:48 ` David Rientjes 2014-06-04 16:11 ` [RFC PATCH 5/6] mm, compaction: try to capture the just-created high-order freepage Vlastimil Babka 2014-06-04 16:11 ` Vlastimil Babka 2014-06-04 16:11 ` [RFC PATCH 6/6] mm, compaction: don't migrate in blocks that cannot be fully compacted in async direct compaction Vlastimil Babka 2014-06-04 16:11 ` Vlastimil Babka 2014-06-05 0:08 ` David Rientjes 2014-06-05 0:08 ` David Rientjes 2014-06-05 15:38 ` Vlastimil Babka 2014-06-05 15:38 ` Vlastimil Babka 2014-06-05 21:38 ` David Rientjes 2014-06-05 21:38 ` David Rientjes 2014-06-06 7:33 ` Vlastimil Babka 2014-06-06 7:33 ` Vlastimil Babka 2014-06-09 9:06 ` David Rientjes 2014-06-09 9:06 ` David Rientjes 2014-06-12 12:18 ` Vlastimil Babka 2014-06-12 12:18 ` Vlastimil Babka 2014-06-04 23:39 ` [RFC PATCH 1/6] mm, compaction: periodically drop lock and restore IRQs in scanners David Rientjes 2014-06-04 23:39 ` David Rientjes 2014-06-05 9:05 ` Vlastimil Babka 2014-06-05 9:05 ` Vlastimil Babka 2014-05-22 23:49 ` [PATCH v2] mm, compaction: properly signal and act upon lock and need_sched() contention Kevin Hilman 2014-05-22 23:49 ` Kevin Hilman 2014-05-23 2:48 ` Shawn Guo 2014-05-23 2:48 ` Shawn Guo 2014-05-23 2:48 ` Shawn Guo 2014-05-23 8:34 ` Vlastimil Babka 2014-05-23 8:34 ` Vlastimil Babka 2014-05-23 8:34 ` Vlastimil Babka 2014-05-23 10:49 ` Shawn Guo 2014-05-23 10:49 ` Shawn Guo 2014-05-23 10:49 ` Shawn Guo 2014-05-23 15:07 ` Kevin Hilman 2014-05-23 15:07 ` Kevin Hilman 2014-05-23 15:07 ` Kevin Hilman 2014-05-30 16:59 ` Stephen Warren 2014-05-30 16:59 ` Stephen Warren 2014-05-30 16:59 ` Stephen Warren 2014-06-02 13:35 ` Fabio Estevam 2014-06-02 13:35 ` Fabio Estevam 2014-06-02 13:35 ` Fabio Estevam 2014-06-02 14:33 ` [PATCH -mm] mm, compaction: properly signal and act upon lock and need_sched() contention - fix Vlastimil Babka 2014-06-02 14:33 ` Vlastimil Babka 2014-06-02 14:33 ` Vlastimil Babka 2014-06-02 15:18 ` Fabio Estevam 2014-06-02 15:18 ` Fabio Estevam 2014-06-02 15:18 ` Fabio Estevam 2014-06-02 20:09 ` David Rientjes 2014-06-02 20:09 ` David Rientjes 2014-06-02 20:09 ` David Rientjes 2014-05-02 13:16 ` [patch 1/2] mm, migration: add destination page freeing callback Vlastimil Babka 2014-05-02 13:16 ` Vlastimil Babka
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