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| author | Wei Yang <richard.weiyang@gmail.com> | 2018-12-28 00:37:10 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-28 12:11:49 -0800 |
| commit | fa004ab7365ffa1e17e6b267d64798afccb94946 (patch) | |
| tree | a0b1c60eac4511b3c4813da3865f683e82eaa7c4 /mm/memory_hotplug.c | |
| parent | 4e0d2e7ef14d9e1c900dac909db45263822b824f (diff) | |
| download | linux-fa004ab7365ffa1e17e6b267d64798afccb94946.tar.gz | |
mm, hotplug: move init_currently_empty_zone() under zone_span_lock protection
During online_pages phase, pgdat->nr_zones will be updated in case this zone is empty. Currently the online_pages phase is protected by the global locks (device_device_hotplug_lock and mem_hotplug_lock), which ensures there is no contention during the update of nr_zones. These global locks introduces scalability issues (especially the second one), which slow down code relying on get_online_mems(). This is also a preparation for not having to rely on get_online_mems() but instead some more fine grained locks. The patch moves init_currently_empty_zone under both zone_span_writelock and pgdat_resize_lock because both the pgdat state is changed (nr_zones) and the zone's start_pfn. Also this patch changes the documentation of node_size_lock to include the protection of nr_zones. Link: http://lkml.kernel.org/r/20181203205016.14123-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory_hotplug.c')
| -rw-r--r-- | mm/memory_hotplug.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 5f15f9c04c4a..c2b34ec602ee 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -743,14 +743,13 @@ void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, int nid = pgdat->node_id; unsigned long flags; - if (zone_is_empty(zone)) - init_currently_empty_zone(zone, start_pfn, nr_pages); - clear_zone_contiguous(zone); /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */ pgdat_resize_lock(pgdat, &flags); zone_span_writelock(zone); + if (zone_is_empty(zone)) + init_currently_empty_zone(zone, start_pfn, nr_pages); resize_zone_range(zone, start_pfn, nr_pages); zone_span_writeunlock(zone); resize_pgdat_range(pgdat, start_pfn, nr_pages); |