[PATCH 1/9] mm: rcu read lock for getting reference on pages in migration_entry_wait()
From: Michel Lespinasse <hidden>
Date: 2011-08-19 07:48:56
Also in:
lkml
Subsystem:
memory management, memory management - memory policy and migration, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
migration_entry_wait() needs to take the rcu read lock so that page counts can be guaranteed to be stable after one rcu grace period. Signed-off-by: Michel Lespinasse <redacted> --- mm/migrate.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index 666e4e6..6f3b5db 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c@@ -193,6 +193,7 @@ void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, struct page *page; ptep = pte_offset_map_lock(mm, pmd, address, &ptl); + rcu_read_lock(); pte = *ptep; if (!is_swap_pte(pte)) goto out;
@@ -212,11 +213,13 @@ void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, */ if (!get_page_unless_zero(page)) goto out; + rcu_read_unlock(); pte_unmap_unlock(ptep, ptl); wait_on_page_locked(page); put_page(page); return; out: + rcu_read_unlock(); pte_unmap_unlock(ptep, ptl); }
--
1.7.3.1
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