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SubjectRe: [PATCH v4 1/4] mm: reduce the rcu lock duration
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On 30.05.22 13:30, Miaohe Lin wrote:
> Commit 3268c63eded4 ("mm: fix move/migrate_pages() race on task struct")
> extends the period of the rcu_read_lock until after the permissions checks
> are done to prevent the task pointed to from changing from under us. But
> the task_struct refcount is also taken at that time, the reference to task
> is guaranteed to be stable. So it's unnecessary to extend the period of
> the rcu_read_lock. Release the rcu lock after task refcount is successfully
> grabbed to reduce the rcu holding time.
>
> Reviewed-by: Muchun Song <songmuchun@bytedance.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Oscar Salvador <osalvador@suse.de>
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> Cc: Huang Ying <ying.huang@intel.com>
> Cc: David Howells <dhowells@redhat.com>
> Cc: Christoph Lameter <cl@linux.com>


Reviewed-by: David Hildenbrand <david@redhat.com>

--
Thanks,

David / dhildenb

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