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Date: Mon, 3 May 2010 14:26:59 -0700
Message-ID: <m2yd6200be21005031426n87ea43a0k968fd5898ce0b873@mail.gmail.com>
Subject: Re: [PATCH 2/8] PM: suspend_block: Add driver to access suspend 
	blockers from user-space
From: =?ISO-8859-1?Q?Arve_Hj=F8nnev=E5g?= <arve@android.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Alan Stern <stern@rowland.harvard.edu>,
       Linux-pm mailing list <linux-pm@lists.linux-foundation.org>,
       Kernel development list <linux-kernel@vger.kernel.org>,
       Tejun Heo <tj@kernel.org>, Oleg Nesterov <oleg@redhat.com>,
       Randy Dunlap <rdunlap@xenotime.net>,
       Andrew Morton <akpm@linux-foundation.org>,
       Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>,
       Jim Collar <jim.collar@eqware.net>, Greg Kroah-Hartman <gregkh@suse.de>,
       Avi Kivity <avi@redhat.com>, Len Brown <len.brown@intel.com>,
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       Nigel Cunningham <nigel@tuxonice.net>, linux-doc@vger.kernel.org
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On Mon, May 3, 2010 at 8:03 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> On Sunday 02 May 2010, Alan Stern wrote:
>> On Sun, 2 May 2010, Rafael J. Wysocki wrote:
>>
>> > Hmm.  It doesn't seem to be possible to create two different suspend blockers
>> > using the same file handle.  So, what exactly is a process supposed to do to
>> > use two suspend blockers at the same time?
>>
>> Open the file twice, thereby obtaining two file handles.
>
> Well, that's what I thought.
>
> I must admit I'm not really comfortable with this interface.  IMO it would
> be better if _open() created the suspend blocker giving it a name based on
> the name of the process that called it.  Something like
> "<process name>_<timestamp>" might work at first sight.
>
> Alternatively, "<process_name><number>", where <number> is 0 for the first
> suspend blocker created by the given process, 1 for the second one etc., also
> seems to be doable.

I think it is important to let user-space specify the name. If a
process uses multiple suspend blockers, it is impossible to tell what
each one is used for if they are automatically named.

-- 
Arve Hjønnevåg