Message-ID: <4C5B3C65.8060703@zytor.com>
Date: Thu, 05 Aug 2010 15:34:13 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Kay Sievers <kay.sievers@vrfy.org>
CC: Greg KH <gregkh@suse.de>, john stultz <johnstul@us.ibm.com>,
        Alexander Shishkin <virtuoso@slind.org>, lkml@vger.kernel.org,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Thomas Gleixner <tglx@linutronix.de>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jon Hunter <jon-hunter@ti.com>, Ingo Molnar <mingo@elte.hu>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        David Howells <dhowells@redhat.com>, Avi Kivity <avi@redhat.com>,
        John Kacur <jkacur@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [RFC] notify userspace about time changes
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On 08/05/2010 03:22 PM, Kay Sievers wrote:
> 
> I think that's really awkward interface, to pass file descriptor
> numbers around and write them to magic sysfs files.
> 
> I would very much prefer a file that contains the current time, and
> wakes up possible users with a POLL_ERR on changes caused by some
> other process. That works very well for things like /proc/mounts, is
> easy to get, and does not need a full page of weird instructions to
> get stuff done. :)
> 

Okay, what's wrong with having a file descriptor that gets *written to*
on a notification?  Why POLL_ERR?

	-hpa
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