diff options
| 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 | |
| parent | 4e0d2e7ef14d9e1c900dac909db45263822b824f (diff) | |
| download | linux-fa004ab7365ffa1e17e6b267d64798afccb94946.tar.bz2 | |
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>
| -rw-r--r-- | include/linux/mmzone.h | 4 | ||||
| -rw-r--r-- | mm/memory_hotplug.c | 5 |
2 files changed, 4 insertions, 5 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index fc4b5cdb6c2d..cc4a507d7ca4 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -636,8 +636,8 @@ typedef struct pglist_data { #endif #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT) /* - * Must be held any time you expect node_start_pfn, node_present_pages - * or node_spanned_pages stay constant. + * Must be held any time you expect node_start_pfn, + * node_present_pages, node_spanned_pages or nr_zones to stay constant. * * pgdat_resize_lock() and pgdat_resize_unlock() are provided to * manipulate node_size_lock without checking for CONFIG_MEMORY_HOTPLUG 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); |