From: Miaohe Lin <linmiaohe@huawei.com>
To: <akpm@linux-foundation.org>
Cc: <mike.kravetz@oracle.com>, <shy828301@gmail.com>,
<willy@infradead.org>, <ying.huang@intel.com>, <ziy@nvidia.com>,
<minchan@kernel.org>, <apopple@nvidia.com>,
<dave.hansen@linux.intel.com>, <o451686892@gmail.com>,
<jhubbard@nvidia.com>, <peterx@redhat.com>,
<naoya.horiguchi@nec.com>, <mhocko@suse.com>, <riel@redhat.com>,
<osalvador@suse.de>, <david@redhat.com>, <sfr@canb.auug.org.au>,
<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
<linmiaohe@huawei.com>
Subject: [PATCH 1/4] mm/migration: reduce the rcu lock duration
Date: Sat, 9 Apr 2022 15:38:43 +0800 [thread overview]
Message-ID: <20220409073846.22286-2-linmiaohe@huawei.com> (raw)
In-Reply-To: <20220409073846.22286-1-linmiaohe@huawei.com>
rcu_read_lock is required by grabbing the task refcount but it's not
needed for ptrace_may_access. So we could release the rcu lock after
task refcount is successfully grabbed to reduce the rcu holding time.
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
mm/migrate.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index a3d8c2be2631..d8aae6c75990 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1907,17 +1907,16 @@ static struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes)
return ERR_PTR(-ESRCH);
}
get_task_struct(task);
+ rcu_read_unlock();
/*
* Check if this process has the right to modify the specified
* process. Use the regular "ptrace_may_access()" checks.
*/
if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
- rcu_read_unlock();
mm = ERR_PTR(-EPERM);
goto out;
}
- rcu_read_unlock();
mm = ERR_PTR(security_task_movememory(task));
if (IS_ERR(mm))
--
2.23.0
next prev parent reply other threads:[~2022-04-09 7:39 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-09 7:38 [PATCH 0/4] A few cleanup and fixup patches for migration Miaohe Lin
2022-04-09 7:38 ` Miaohe Lin [this message]
2022-04-11 14:09 ` [PATCH 1/4] mm/migration: reduce the rcu lock duration Christoph Hellwig
2022-04-12 2:07 ` ying.huang
2022-04-12 3:21 ` Miaohe Lin
2022-04-09 7:38 ` [PATCH 2/4] mm/migration: remove unneeded lock page and PageMovable check Miaohe Lin
2022-04-11 14:09 ` Christoph Hellwig
2022-04-09 7:38 ` [PATCH 3/4] mm/migration: return errno when isolate_huge_page failed Miaohe Lin
2022-04-11 14:10 ` Christoph Hellwig
2022-04-12 3:13 ` Miaohe Lin
2022-04-09 7:38 ` [PATCH 4/4] mm/migration: fix potential pte_unmap on an not mapped pte Miaohe Lin
2022-04-09 11:38 ` kernel test robot
2022-04-11 1:54 ` Miaohe Lin
2022-04-11 11:41 ` David Hildenbrand
2022-04-12 2:55 ` Miaohe Lin
2022-04-12 2:25 ` [PATCH 0/4] A few cleanup and fixup patches for migration ying.huang
2022-04-12 3:29 ` Miaohe Lin
2022-04-12 6:33 ` ying.huang
2022-04-12 8:59 ` Miaohe Lin
2022-04-12 7:00 ` ying.huang
2022-04-12 9:06 ` Miaohe Lin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220409073846.22286-2-linmiaohe@huawei.com \
--to=linmiaohe@huawei.com \
--cc=akpm@linux-foundation.org \
--cc=apopple@nvidia.com \
--cc=dave.hansen@linux.intel.com \
--cc=david@redhat.com \
--cc=jhubbard@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=mike.kravetz@oracle.com \
--cc=minchan@kernel.org \
--cc=naoya.horiguchi@nec.com \
--cc=o451686892@gmail.com \
--cc=osalvador@suse.de \
--cc=peterx@redhat.com \
--cc=riel@redhat.com \
--cc=sfr@canb.auug.org.au \
--cc=shy828301@gmail.com \
--cc=willy@infradead.org \
--cc=ying.huang@intel.com \
--cc=ziy@nvidia.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).