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From: Peter Zijlstra <peterz@infradead.org>
To: Huang Ying <ying.huang@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [PATCH -mm 1/2] irq_work, Use llist in irq_work
Date: Thu, 01 Sep 2011 11:57:15 +0200	[thread overview]
Message-ID: <1314871035.7945.14.camel@twins> (raw)
In-Reply-To: <4E5F48D1.801@intel.com>

On Thu, 2011-09-01 at 16:56 +0800, Huang Ying wrote:
> Something as follow with llist_empty() seems not work.
> 
>   empty = llist_empty(irq_work_list);
>   llist_add(&work->llnode, irq_work_list);
>   if (empty)
>           arch_irq_work_raise();
> 
> Because irq_work IRQ handler or timer IRQ handler may be executed just
> before "llist_add(&work->llnode, irq_work_list)", so that, although
> "empty == false", arch_irq_work_raise() still should be executed.

Right, I was thinking:

	llist_add(&work->llist, irq_work_list);
	if (llist_empty(&work->llist))
		arch_irq_work_raise();

And then ran into the difference between llist_node and llist_head. Now
we could sort that by introducing llist_next() and write it like:

	if (!llist_next(&work->list))
		arch_irq_work_raise();



  reply	other threads:[~2011-09-01  9:57 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-30  5:16 [PATCH -mm 0/2] Use llist in irq_work and xlist Huang Ying
2011-08-30  5:16 ` [PATCH -mm 1/2] irq_work, Use llist in irq_work Huang Ying
2011-08-31 10:10   ` Peter Zijlstra
2011-09-01  1:46     ` Huang Ying
2011-09-01  3:20       ` Huang Ying
2011-09-01  7:58         ` Peter Zijlstra
2011-09-01  8:56           ` Huang Ying
2011-09-01  9:57             ` Peter Zijlstra [this message]
2011-09-02  1:14               ` Huang Ying
2011-09-03 17:35                 ` Mathieu Desnoyers
2011-09-01 12:51             ` Mathieu Desnoyers
2011-09-01 13:00               ` Mathieu Desnoyers
2011-09-02  1:08               ` Huang Ying
2011-09-03 16:33                 ` Mathieu Desnoyers
2011-09-01  7:57       ` Peter Zijlstra
2011-09-01  8:44         ` Huang Ying
2011-09-01 10:00           ` Peter Zijlstra
2011-09-02  1:18             ` Huang Ying
2011-09-02 13:26               ` Peter Zijlstra
2011-08-30  5:16 ` [PATCH -mm 2/2] net, rds, Replace xlist in net/rds/xlist.h with llist Huang Ying

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