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| author | Arun KS <arunks@codeaurora.org> | 2018-12-28 00:34:24 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-28 12:11:47 -0800 |
| commit | 9705bea5f833f4fc21d5bef5fce7348427f76ea4 (patch) | |
| tree | 37604aa5b680736eb176283f970e1c1d7d27bbf3 /mm/memblock.c | |
| parent | 3d6357de8aa09e1966770dc1171c72679946464f (diff) | |
| download | lwn-9705bea5f833f4fc21d5bef5fce7348427f76ea4.tar.gz lwn-9705bea5f833f4fc21d5bef5fce7348427f76ea4.zip | |
mm: convert zone->managed_pages to atomic variable
totalram_pages, zone->managed_pages and totalhigh_pages updates are
protected by managed_page_count_lock, but readers never care about it.
Convert these variables to atomic to avoid readers potentially seeing a
store tear.
This patch converts zone->managed_pages. Subsequent patches will convert
totalram_panges, totalhigh_pages and eventually managed_page_count_lock
will be removed.
Main motivation was that managed_page_count_lock handling was complicating
things. It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes
better to remove the lock and convert variables to atomic, with preventing
poteintial store-to-read tearing as a bonus.
Link: http://lkml.kernel.org/r/1542090790-21750-3-git-send-email-arunks@codeaurora.org
Signed-off-by: Arun KS <arunks@codeaurora.org>
Suggested-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memblock.c')
| -rw-r--r-- | mm/memblock.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/memblock.c b/mm/memblock.c index 81ae63ca78d0..0068f87af1e8 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1950,7 +1950,7 @@ void reset_node_managed_pages(pg_data_t *pgdat) struct zone *z; for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) - z->managed_pages = 0; + atomic_long_set(&z->managed_pages, 0); } void __init reset_all_zones_managed_pages(void) |