From 631953991185130a4a0fa7c643e8a8effe7f732d Mon Sep 17 00:00:00 2001
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Date: Mon, 23 Sep 2019 15:37:01 -0700
Subject: [PATCH] mm/mempolicy.c: remove unnecessary nodemask check in
kernel_migrate_pages()
References: bnc#1155780 (VM/FS functional and performance backports)
Patch-mainline: v5.4-rc1
Git-commit: 4406548ee39c2268876b61a927acad45da6f9aef
1) task_nodes = cpuset_mems_allowed(current);
-> cpuset_mems_allowed() guaranteed to return some non-empty
subset of node_states[N_MEMORY].
2) nodes_and(*new, *new, task_nodes);
-> after nodes_and(), the 'new' should be empty or appropriate
nodemask(online node and with memory).
After 1) and 2), we could remove unnecessary check whether the 'new'
AND node_states[N_MEMORY] is empty.
Link: http://lkml.kernel.org/r/20190806023634.55356-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/mempolicy.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 65e0874fce17..5ff884dd25b0 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1513,10 +1513,6 @@ static int kernel_migrate_pages(pid_t pid, unsigned long maxnode,
if (nodes_empty(*new))
goto out_put;
- nodes_and(*new, *new, node_states[N_MEMORY]);
- if (nodes_empty(*new))
- goto out_put;
-
err = security_task_movememory(task);
if (err)
goto out_put;