diff mbox series

[159/181] mm/mempolicy: remove or narrow the lock on current

Message ID 20201013235708.jAS0Gx_Zg%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [001/181] compiler-clang: add build check for clang 10.0.1 | expand

Commit Message

Andrew Morton Oct. 13, 2020, 11:57 p.m. UTC 
From: Wei Yang <richard.weiyang@linux.alibaba.com>
Subject: mm/mempolicy: remove or narrow the lock on current

It is not necessary to hold the lock of current when setting nodemask of
a new policy.

Link: https://lkml.kernel.org/r/20200921040416.86185-1-richard.weiyang@linux.alibaba.com
Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mempolicy.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)
diff mbox series

Patch

--- a/mm/mempolicy.c~mm-mempolicy-remove-or-narrow-the-lock-on-current
+++ a/mm/mempolicy.c
@@ -875,13 +875,12 @@  static long do_set_mempolicy(unsigned sh
 		goto out;
 	}
 
-	task_lock(current);
 	ret = mpol_set_nodemask(new, nodes, scratch);
 	if (ret) {
-		task_unlock(current);
 		mpol_put(new);
 		goto out;
 	}
+	task_lock(current);
 	old = current->mempolicy;
 	current->mempolicy = new;
 	if (new && new->mode == MPOL_INTERLEAVE)
@@ -1324,9 +1323,7 @@  static long do_mbind(unsigned long start
 		NODEMASK_SCRATCH(scratch);
 		if (scratch) {
 			mmap_write_lock(mm);
-			task_lock(current);
 			err = mpol_set_nodemask(new, nmask, scratch);
-			task_unlock(current);
 			if (err)
 				mmap_write_unlock(mm);
 		} else