From: Abel Wu <wuyun.abel@bytedance.com>
To: akpm@linux-foundation.org, lizefan.x@bytedance.com,
tj@kernel.org, hannes@cmpxchg.org, corbet@lwn.net
Cc: cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
Abel Wu <wuyun.abel@bytedance.com>
Subject: [PATCH 1/3] mm/mempolicy: apply cpuset limits to tasks using default policy
Date: Mon, 26 Apr 2021 14:59:44 +0800 [thread overview]
Message-ID: <20210426065946.40491-2-wuyun.abel@bytedance.com> (raw)
In-Reply-To: <20210426065946.40491-1-wuyun.abel@bytedance.com>
The nodemasks of non-default policies (pol->v) are calculated within
the restriction of task->mems_allowed, while default policies are not.
This may lead to improper results of mpol_misplaced(), since it can
return a target node outside of current->mems_allowed for tasks using
default policies. Although this is not a bug because migrating pages
to that out-of-cpuset node will fail eventually due to sanity checks
in page allocation, it still would be better to avoid such useless
efforts.
This patch also changes the behavior of autoNUMA a bit by showing
a tendency to move pages inside mems_allowed for tasks using default
policies, which is good for memory isolation.
Signed-off-by: Abel Wu <wuyun.abel@bytedance.com>
---
mm/mempolicy.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d79fa299b70c..e0ae6997bbfb 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2516,7 +2516,10 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
/* Migrate the page towards the node whose CPU is referencing it */
if (pol->flags & MPOL_F_MORON) {
- polnid = thisnid;
+ if (node_isset(thisnid, cpuset_current_mems_allowed))
+ polnid = thisnid;
+ else
+ polnid = node_random(&cpuset_current_mems_allowed);
if (!should_numa_migrate_memory(current, page, curnid, thiscpu))
goto out;
--
2.31.1
next prev parent reply other threads:[~2021-04-26 7:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-26 6:59 [PATCH 0/3] cgroup2: introduce cpuset.mems.migration Abel Wu
2021-04-26 6:59 ` Abel Wu [this message]
2021-04-26 6:59 ` [PATCH 2/3] cgroup/cpuset: " Abel Wu
2021-04-27 14:43 ` Tejun Heo
2021-04-28 7:24 ` Abel Wu
2021-05-05 5:06 ` [Phishing Risk] [External] " Abel Wu
2021-05-05 22:30 ` Johannes Weiner
2021-04-26 6:59 ` [PATCH 3/3] docs/admin-guide/cgroup-v2: add cpuset.mems.migration Abel Wu
-- strict thread matches above, loose matches on Subject: below --
2021-04-22 9:06 [PATCH 0/3] cgroup2: introduce cpuset.mems.migration Abel Wu
2021-04-22 9:06 ` [PATCH 1/3] mm/mempolicy: apply cpuset limits to tasks using default policy Abel Wu
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