From: Tejun Heo <tj@kernel.org>
To: Jeff Layton <jlayton@redhat.com>
Cc: rjw@sisk.pl, linux-nfs@vger.kernel.org, linux-pm@vger.kernel.org,
john@calva.com, trond.myklebust@netapp.com
Subject: Re: [PATCH 1/2] sunrpc: make rpc_wait_bit_killable handle freeze events
Date: Mon, 21 Nov 2011 12:41:41 -0800 [thread overview]
Message-ID: <20111121204141.GD25776@google.com> (raw)
In-Reply-To: <20111121153615.7e876801@corrin.poochiereds.net>
Hello, Jeff.
On Mon, Nov 21, 2011 at 03:36:15PM -0500, Jeff Layton wrote:
> I suppose you're suggesting something like this?
>
> freezer_do_not_count();
> if (!try_to_freeze())
> schedule();
> freezer_count();
No,
freezer_do_not_count();
schedule();
freezer_count();
try_to_freeze();
freezer_count() may make %current eligible for freezing again, so it
has to check whether freezing condition is pending afterwards.
> The freezer is not really my forte', but I have to say that the whole
> do_not_count scheme seems "sketchy". Would we not be better off with
> something closer to the original method that I proposed, along with a
> new TASK_WAKEFREEZE state bit? Processes that are sleeping in
> uninterruptible sleep that are able to deal with freezer events could
> set that bit and fake_signal_wake_up could be changed to also wake
> processes with that bit set.
AFAICS, the above should be race-free w/ the pending freezer update.
http://git.kernel.org/?p=linux/kernel/git/tj/misc.git;a=shortlog;h=refs/heads/pm-freezer
Thank you.
--
tejun
next prev parent reply other threads:[~2011-11-21 20:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-21 17:40 [PATCH 0/2] nfs/sunrpc: allow freezing of tasks with NFS calls in flight Jeff Layton
2011-11-21 17:40 ` [PATCH 1/2] sunrpc: make rpc_wait_bit_killable handle freeze events Jeff Layton
2011-11-21 17:56 ` Tejun Heo
2011-11-21 20:36 ` Jeff Layton
2011-11-21 20:41 ` Tejun Heo [this message]
2011-11-21 20:42 ` Tejun Heo
2011-11-21 20:46 ` Tejun Heo
2011-11-21 20:57 ` Jeff Layton
2011-11-21 17:40 ` [PATCH 2/2] nfs: make TASK_KILLABLE sleeps attempt to freeze Jeff Layton
-- strict thread matches above, loose matches on Subject: below --
2011-10-28 6:08 [PATCH 1/2] sunrpc: make rpc_wait_bit_killable handle freeze events Jeff Layton
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