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From: "tj@kernel.org" <tj@kernel.org>
To: Bart Van Assche <Bart.VanAssche@wdc.com>
Cc: "jthumshirn@suse.de" <jthumshirn@suse.de>,
	"hch@lst.de" <hch@lst.de>,
	"martin@lichtvoll.de" <martin@lichtvoll.de>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"ming.lei@redhat.com" <ming.lei@redhat.com>,
	"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"oleksandr@natalenko.name" <oleksandr@natalenko.name>,
	"hare@suse.com" <hare@suse.com>,
	"jejb@linux.vnet.ibm.com" <jejb@linux.vnet.ibm.com>
Subject: Re: [PATCH] Change synchronize_rcu() in scsi_device_quiesce() into synchronize_sched()
Date: Mon, 19 Mar 2018 09:29:21 -0700	[thread overview]
Message-ID: <20180319162921.GS2943022@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <1521476333.2776.9.camel@wdc.com>

Hello,

On Mon, Mar 19, 2018 at 04:18:54PM +0000, Bart Van Assche wrote:
> The algorithm explained above does not depend on sched-rcu. But because
> percpu_ref_tryget_live() uses sched-rcu and because we need to add an RCU lock
> around that call we are forced to use sched-rcu. I hope this makes it clear.

This could be me being slow but can you explain how what
percpu_ref_tryget_live() uses internally affects whether we can use
regular RCU around it?

Thanks.

-- 
tejun

  reply	other threads:[~2018-03-19 16:29 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-16 17:35 [PATCH] Change synchronize_rcu() in scsi_device_quiesce() into synchronize_sched() Bart Van Assche
2018-03-16 21:42 ` Martin Steigerwald
2018-03-16 21:42   ` Martin Steigerwald
2018-03-16 21:51   ` Bart Van Assche
2018-03-19  9:02     ` Martin Steigerwald
2018-03-19 14:31 ` Tejun Heo
2018-03-19 15:16   ` Bart Van Assche
2018-03-19 15:21     ` tj
2018-03-19 16:18       ` Bart Van Assche
2018-03-19 16:29         ` tj [this message]
2018-03-19 16:57           ` Bart Van Assche
2018-03-19 17:02             ` tj
2018-03-19 20:19               ` Bart Van Assche
2018-03-19 20:19                 ` Bart Van Assche

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