From: Ming Lei <ming.lei@redhat.com>
To: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"hch@infradead.org" <hch@infradead.org>,
"jejb@linux.vnet.ibm.com" <jejb@linux.vnet.ibm.com>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"axboe@fb.com" <axboe@fb.com>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"jthumshirn@suse.de" <jthumshirn@suse.de>,
"martin@lichtvoll.de" <martin@lichtvoll.de>,
"oleksandr@natalenko.name" <oleksandr@natalenko.name>,
"hare@suse.com" <hare@suse.com>, "tj@kernel.org" <tj@kernel.org>,
"cavery@redhat.com" <cavery@redhat.com>
Subject: Re: [PATCH V8 5/8] percpu-refcount: introduce __percpu_ref_tryget_live
Date: Wed, 4 Oct 2017 03:24:13 +0800 [thread overview]
Message-ID: <20171003192412.GC5362@ming.t460p> (raw)
In-Reply-To: <1507056023.2567.1.camel@wdc.com>
On Tue, Oct 03, 2017 at 06:40:24PM +0000, Bart Van Assche wrote:
> On Tue, 2017-10-03 at 22:04 +0800, Ming Lei wrote:
> > Block layer need to call this function after holding
> > rcu lock in a real hot path, so introduce this helper.
>
> Since it is allowed to nest rcu_read_lock_sched() calls I don't think
> that this patch is necessary.
Yeah, I know that, with this patch, we can avoid the nest RCU lock.
As I mentioned, it is a real hot path, so maybe better to not
introduce the extra RCU read lock/unlock.
If you guys doesn't care the little cost, I can remove that.
--
Ming
next prev parent reply other threads:[~2017-10-03 19:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-03 14:03 [PATCH V8 0/8] block/scsi: safe SCSI quiescing Ming Lei
2017-10-03 14:03 ` [PATCH V8 1/8] blk-mq: only run hw queues for blk-mq Ming Lei
2017-10-03 14:04 ` [PATCH V8 2/8] block: tracking request allocation with q_usage_counter Ming Lei
2017-10-03 14:04 ` [PATCH V8 3/8] block: Convert RQF_PREEMPT into REQ_PREEMPT Ming Lei
2017-10-03 14:04 ` [PATCH V8 4/8] block: pass 'op' to blk_queue_enter() Ming Lei
2017-10-03 14:04 ` [PATCH V8 5/8] percpu-refcount: introduce __percpu_ref_tryget_live Ming Lei
2017-10-03 14:14 ` Tejun Heo
2017-10-03 19:20 ` Ming Lei
2017-10-03 19:31 ` Tejun Heo
2017-10-03 18:40 ` Bart Van Assche
2017-10-03 19:24 ` Ming Lei [this message]
2017-10-03 14:04 ` [PATCH V8 6/8] blk-mq: return if queue is frozen via current blk_freeze_queue_start Ming Lei
2017-10-03 14:04 ` [PATCH V8 7/8] block: support PREEMPT_ONLY Ming Lei
2017-10-03 14:04 ` [PATCH V8 8/8] SCSI: set block queue at preempt only when SCSI device is put into quiesce Ming Lei
2017-10-03 18:27 ` [PATCH V8 0/8] block/scsi: safe SCSI quiescing Oleksandr Natalenko
2017-11-07 12:32 ` Oleksandr Natalenko
2017-11-07 13:17 ` Ming Lei
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