From patchwork Wed May 8 09:47:22 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Byungchul Park X-Patchwork-Id: 13658410 Received: from invmail4.hynix.com (exvmail4.skhynix.com [166.125.252.92]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6D8817E794; Wed, 8 May 2024 10:02:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=166.125.252.92 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715162584; cv=none; b=ryyxGPiCIr3mkH72mIbuqI5UBHprYgEVTwV0jSgOdl6X7bWWQ5IHXjTx8cDpAqNfyxZh7LVxIJRVzQZeOc1O/atS7QPFUQLxM0ILalmsGaS0u3vcV+Xhx4TrkKsugb8IvAEdbDoAkhmHBJK7B0ZJ3QorsUdWw/bwo5HusvNBwuA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715162584; c=relaxed/simple; bh=cVjts9SZXZ4NmM7fBk0URrytFXU4oROO3YR0wv1o+Nc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=Scj2Eq9yFOTMu+zM0x/q1NiQybbPmtcAsrC99J3WEZFDJhJQVEEp/7lB7ghk6QKnbRKg071cElc4/ri96rsYo3PEQlMPUezqcLDUV0OS8Clk7vwXJzjNNPfzbPTvfkL8nA39B2PW3RwgUaZoIp6+/749Ef3qobFMULbLeW7kzOE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com; spf=pass smtp.mailfrom=sk.com; arc=none smtp.client-ip=166.125.252.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sk.com X-AuditID: a67dfc5b-d85ff70000001748-a9-663b4a3b9061 From: Byungchul Park To: linux-kernel@vger.kernel.org Cc: kernel_team@skhynix.com, torvalds@linux-foundation.org, damien.lemoal@opensource.wdc.com, linux-ide@vger.kernel.org, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, mingo@redhat.com, peterz@infradead.org, will@kernel.org, tglx@linutronix.de, rostedt@goodmis.org, joel@joelfernandes.org, sashal@kernel.org, daniel.vetter@ffwll.ch, duyuyang@gmail.com, johannes.berg@intel.com, tj@kernel.org, tytso@mit.edu, willy@infradead.org, david@fromorbit.com, amir73il@gmail.com, gregkh@linuxfoundation.org, kernel-team@lge.com, linux-mm@kvack.org, akpm@linux-foundation.org, mhocko@kernel.org, minchan@kernel.org, hannes@cmpxchg.org, vdavydov.dev@gmail.com, sj@kernel.org, jglisse@redhat.com, dennis@kernel.org, cl@linux.com, penberg@kernel.org, rientjes@google.com, vbabka@suse.cz, ngupta@vflare.org, linux-block@vger.kernel.org, josef@toxicpanda.com, linux-fsdevel@vger.kernel.org, jack@suse.cz, jlayton@kernel.org, dan.j.williams@intel.com, hch@infradead.org, djwong@kernel.org, dri-devel@lists.freedesktop.org, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, 42.hyeyoo@gmail.com, chris.p.wilson@intel.com, gwan-gyeong.mun@intel.com, max.byungchul.park@gmail.com, boqun.feng@gmail.com, longman@redhat.com, hdanton@sina.com, her0gyugyu@gmail.com Subject: [PATCH v14 25/28] cpu/hotplug: Use a weaker annotation in AP thread Date: Wed, 8 May 2024 18:47:22 +0900 Message-Id: <20240508094726.35754-26-byungchul@sk.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20240508094726.35754-1-byungchul@sk.com> References: <20240508094726.35754-1-byungchul@sk.com> X-Brightmail-Tracker: H4sIAAAAAAAAAzWSbVBMYRTHPc+9e+/dtWvurEy3fMBizHjXiEMGX+RhNON1zPCBHd20VMyW khmjN7VKiKklTWplrUrYXeOtzVpKiYRFmoQySG2Z2J2ykW3x5cxv/ud/fp8ORymvS4I5TVyC qI1Tx6gYGS1zyUtnha0Oi5r70rQY8o7OBfcPHQ1FVyoZaK6qQFBpTcXQVbsSXnt6EHifPKVA n9+MoPTDWwqsde0IbKY0Bl58HANOdx8DDfk5DKSfv8LAs+4hDG0FJzFUmCOg8YQBg33wMw36 LgbO6tOxb3zBMGgsZ8GYMhU6TIUsDH2YBw3tryRga50BZ4rbGKi2NdBQd7MDw4vbRQy0Vw5L oLGunobmvFwJXO41MNDtMVJgdPex8NxeguFqhk+U+f23BB7m2jFkll3D4HxzB0GN7j0Gc+Ur Bu67ezBYzPkU/LxYi6DjmIuFw0cHWTibegxBzuECGjLaQsE7UMQsX0Tu9/RRJMOSRGyeEpo8 MgjkVuFblmTUtLKkxLyPWEzTyfnqLkxK+90SYi4/whBz/0mWZLucmPQ2NbGk/rSXJh+derw2 eItsSaQYo0kUtXOWbpdF92e1or3vpPtrsr1MChpms5GUE/j5Qn3LKeo/N146hUaY4acJLS2D /jyAnyhYcj9JRpjie2RCWVP4CI/l1wjv2nP8HpqfKngv3fV3FPwCoawz759/glBx1e73SH35 m8+9fr+SDxXupBf6OjJfZ4ATfgwU4L8HQcI9Uwt9AilK0KhypNTEJcaqNTHzZ0cnx2n2z96x J9aMfM9kPDi09Sbqb97gQDyHVHKFPXBxlFKiToxPjnUggaNUAYrarIVRSkWkOvmAqN2zTbsv Rox3oPEcrQpUhHiSIpX8TnWCuFsU94ra/1vMSYNT0KbOtI0/6YigZSG24tDGzOGIx8/bdiyX V+mWrV8S2ek1GF0PP1kLNsPT0bppRn3qzO5zo29/zc3TVWfJJ4WseuzkHNvXSNOG17mORyGT Y8r1RRsm6wOO5BgsF60bEw5FVNmsqlhj+AUi/3ZuV4D9WfiKcb/GesKSxqzfeSMwiMx8oKLj o9XzplPaePUf16XCT0gDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAAzWSfUzMcRzHfX+P183Zbyf8ls3DbQ0ZahyfqWGz6TvP/irm6dIv3XSn3ZFi tnKXhx5MqCPVrgcndZE7DymllYs0OYpIRYmkuibu5tyRavzz2Wvvz+f9+usjIqUG2k+kVB8S NGpFjIwRU+LNwbpFweuDowILC/whIy0QnD9OU5Bz08yA/UYpAvPtJAL6baHQ5hpE4Hn2nARD ph1BfncnCbcbuhBUF59goKV3CrQ6hxlozExlQFd4k4EXA14COrLOE1Bq2QRN5woIqHX3UWDo Z+CKQUeMjS8EuE0lLJgS/aGnOJsFb3cQNHa9pqE+t5GG6vaFcDmvg4EH1Y0UNFT0ENBSmcNA l3mUhqaGJxTYM9JpKHMUMDDgMpFgcg6z8LLWSEC5fsx28vsfGh6n1xJwsugWAa1vqxDUnP5A gMX8moF65yABVksmCb+u2RD0nB1iITnNzcKVpLMIUpOzKNB3yMHzM4dZsxLXDw6TWG89gqtd Rgo/LeDx/exOFutr2llstBzG1uIAXPign8D5I04aW0rOMNgycp7FKUOtBHY0N7P4ySUPhXtb DcTWmTvEIZFCjDJO0CxZtVccPXKqHcW+94mvSfEwiWiUTUE+Ip5bxjddv4DGmeHm8W/euMlx 9uXm8Nb0z/Q4k9ygmC9qXjfOU7mN/Puu1IkuxfnznusPJ24k3HK+6GPGP+dsvrS8dsLjM5a/ 7XNM+KWcnK/SZbPnkNiIJpUgX6U6TqVQxsgXaw9EJ6iV8Yv3HVRZ0Ni7mI57MyrQj5bQOsSJ kGyyxM4ER0lpRZw2QVWHeBEp85XYTq2IkkoiFQlHBc3BPZrDMYK2Ds0UUbIZkvVhwl4pt19x SDggCLGC5v+WEPn4JaLNtPrODoelpMN/+86HLvfa+S+Kpya1lc+aMVT6bbXqq6NnabL1ovnu usextmnJ21TxfRt0fZ2fbtizwjRTorfkelPyNzyafsxbl51XdiQifJJ0ztVl99ZWBNhGExdE yObqYp2B8ULQu4FXvyvDQR4S1l/W5qKLIhSRlN6+y7NbjmWUNloRFEBqtIq/MqLSeSoDAAA= X-CFilter-Loop: Reflected Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: cb92173d1f0 ("locking/lockdep, cpu/hotplug: Annotate AP thread") was introduced to make lockdep_assert_cpus_held() work in AP thread. However, the annotation is too strong for that purpose. We don't have to use more than try lock annotation for that. rwsem_acquire() implies: 1. might be a waiter on contention of the lock. 2. enter to the critical section of the lock. All we need in here is to act 2, not 1. So trylock version of annotation is sufficient for that purpose. Now that dept partially relies on lockdep annotaions, dept interpets rwsem_acquire() as a potential wait and might report a deadlock by the wait. So replaced it with trylock version of annotation. Signed-off-by: Byungchul Park --- kernel/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index 63447eb85dab..da969f7269b5 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -534,7 +534,7 @@ int lockdep_is_cpus_held(void) static void lockdep_acquire_cpus_lock(void) { - rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_); + rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 1, _THIS_IP_); } static void lockdep_release_cpus_lock(void)