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authorArun KS <arunks@codeaurora.org>2018-12-28 08:34:24 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-28 20:11:47 (GMT)
commit9705bea5f833f4fc21d5bef5fce7348427f76ea4 (patch)
tree37604aa5b680736eb176283f970e1c1d7d27bbf3 /lib
parent3d6357de8aa09e1966770dc1171c72679946464f (diff)
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 'lib')
-rw-r--r--lib/show_mem.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/show_mem.c b/lib/show_mem.c
index 0beaa1d..eefe67d 100644
--- a/lib/show_mem.c
+++ b/lib/show_mem.c
@@ -28,7 +28,7 @@ void show_mem(unsigned int filter, nodemask_t *nodemask)
continue;
total += zone->present_pages;
- reserved += zone->present_pages - zone->managed_pages;
+ reserved += zone->present_pages - zone_managed_pages(zone);
if (is_highmem_idx(zoneid))
highmem += zone->present_pages;

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