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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-01-15 16:53:07 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-15 17:56:32 -0800
commit3ac808fdd2b835547af81de75c813cf7ba2ab58f (patch)
tree0c3becb6bc03ab26490c937fe8031419dad91b1e /mm/memcontrol.c
parentksm: prepare to new THP semantics (diff)
downloadlinux-dev-3ac808fdd2b835547af81de75c813cf7ba2ab58f.tar.xz
linux-dev-3ac808fdd2b835547af81de75c813cf7ba2ab58f.zip
mm, thp: remove compound_lock()
We are going to use migration entries to stabilize page counts. It means we don't need compound_lock() for that. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c11
1 files changed, 3 insertions, 8 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 311fd2b71bae..db2a5d9ad886 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2433,9 +2433,7 @@ void __memcg_kmem_uncharge(struct page *page, int order)
/*
* Because tail pages are not marked as "used", set it. We're under
- * zone->lru_lock, 'splitting on pmd' and compound_lock.
- * charge/uncharge will be never happen and move_account() is done under
- * compound_lock(), so we don't have to take care of races.
+ * zone->lru_lock and migration entries setup in all page mappings.
*/
void mem_cgroup_split_huge_fixup(struct page *head)
{
@@ -4507,9 +4505,7 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
* @from: mem_cgroup which the page is moved from.
* @to: mem_cgroup which the page is moved to. @from != @to.
*
- * The caller must confirm following.
- * - page is not on LRU (isolate_page() is useful.)
- * - compound_lock is held when nr_pages > 1
+ * The caller must make sure the page is not on LRU (isolate_page() is useful.)
*
* This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
* from old cgroup.
@@ -4868,8 +4864,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
struct page *page;
/*
- * We don't take compound_lock() here but no race with splitting thp
- * happens because:
+ * No race with splitting thp happens because:
* - if pmd_trans_huge_lock() returns 1, the relevant thp is not
* under splitting, which means there's no concurrent thp split,
* - if another thread runs into split_huge_page() just after we