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authorAndrew Morton <akpm@linux-foundation.org>2018-02-22 01:45:17 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-02-22 02:35:42 +0300
commitd34bc48f8275b6ce0da44f639d68344891268ee9 (patch)
tree4004ff5aceb19f3bbfb5c395e9a5df0f13a7f376 /include
parent7ed1c1901fe52e6c5828deb155920b44b0adabb1 (diff)
downloadlinux-d34bc48f8275b6ce0da44f639d68344891268ee9.tar.xz
include/linux/sched/mm.h: re-inline mmdrop()
As Peter points out, Doing a CALL+RET for just the decrement is a bit silly. Fixes: d70f2a14b72a4bc ("include/linux/sched/mm.h: uninline mmdrop_async(), etc") Acked-by: Peter Zijlstra (Intel) <peterz@infraded.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/sched/mm.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index 1149533aa2fa..9806184bb3d5 100644
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -36,7 +36,18 @@ static inline void mmgrab(struct mm_struct *mm)
atomic_inc(&mm->mm_count);
}
-extern void mmdrop(struct mm_struct *mm);
+extern void __mmdrop(struct mm_struct *mm);
+
+static inline void mmdrop(struct mm_struct *mm)
+{
+ /*
+ * The implicit full barrier implied by atomic_dec_and_test() is
+ * required by the membarrier system call before returning to
+ * user-space, after storing to rq->curr.
+ */
+ if (unlikely(atomic_dec_and_test(&mm->mm_count)))
+ __mmdrop(mm);
+}
/**
* mmget() - Pin the address space associated with a &struct mm_struct.