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Subject: Re: [PATCH -v4] generic-ipi: remove kmalloc()
From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Nick Piggin <npiggin@suse.de>, Jens Axboe <jens.axboe@oracle.com>,
       "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
       Ingo Molnar <mingo@elte.hu>, Rusty Russell <rusty@rustcorp.com.au>,
       Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org
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Date: Tue, 17 Feb 2009 21:11:52 +0100
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On Tue, 2009-02-17 at 21:02 +0100, Oleg Nesterov wrote:

> Argh! Sorry-sorry-sorry. I managed to confused myself and you.
> 
> Please return to the previous version. With this patch we do:
> 
> 		func(info);
> 
> 		if (!refs && wait)
> 			csd_complete();
> 
> but we can't do csd_complete(), we can not be sure other CPUs
> has already passed this function call.
> 
> Of course we can add another counter, but I don't think this
> worth the trouble.

Eek, you're right.

> As for the previous version. I am almost sure I missed something
> again, but do we really need both CSD_FLAG_WAIT and CSD_FLAG_LOCK
> flags? smp_call_function_many(wait => 1) can just wait for
> !CSD_FLAG_LOCK.

I suppose we can.