From: Tejun Heo <tj@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Jeff Layton <jlayton@redhat.com>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
Steve French <sfrench@samba.org>,
linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
linux-cifs@vger.kernel.org,
"J. Bruce Fields" <bfields@fieldses.org>,
Neil Brown <neilb@suse.de>,
trond.myklebust@netapp.com, linux-nfs@vger.kernel.org
Subject: Re: [RFC PATCH] freezer: revert 27920651fe "PM / Freezer: Make fake_signal_wake_up() wake TASK_KILLABLE tasks too"
Date: Tue, 1 Nov 2011 11:06:01 -0700 [thread overview]
Message-ID: <20111101180601.GV18855@google.com> (raw)
In-Reply-To: <20111101175953.GB5358@redhat.com>
On Tue, Nov 01, 2011 at 06:59:53PM +0100, Oleg Nesterov wrote:
> > #define wait_event_freezekillable(wq, condition) \
> > do { \
> > DEFINE_WAIT(__wait); \
> > for (;;) { \
> > prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \
> > if (condition || fatal_signal_pending(current)) \
> > break; \
> > schedule(); \
>
> No, this can't work, afaics.
>
> Once the caller recieves a non-fatal signal (gets TIF_SIGPENDING),
> schedule() won't block in TASK_INTERRUPTIBLE state.
>
> IOW, wait_event_freezekillable() becomes a busy-wait loop.
Yeah yeah, Trond already pointed it out. I forgot about the
sigpending special case in schedule(), which I think is rather odd, oh
well. Any better ideas?
--
tejun
next prev parent reply other threads:[~2011-11-01 18:06 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20111031221743.GA18855@google.com>
[not found] ` <201111010024.16659.rjw@sisk.pl>
[not found] ` <20111031233059.GI18855@google.com>
[not found] ` <20111101005505.GO18855@google.com>
2011-11-01 8:13 ` [RFC PATCH] freezer: revert 27920651fe "PM / Freezer: Make fake_signal_wake_up() wake TASK_KILLABLE tasks too" Jeff Layton
2011-11-01 10:59 ` Jeff Layton
2011-11-01 16:30 ` Tejun Heo
2011-11-01 16:49 ` Trond Myklebust
2011-11-01 16:55 ` Tejun Heo
2011-11-01 17:59 ` Oleg Nesterov
2011-11-01 18:06 ` Tejun Heo [this message]
2011-11-01 18:13 ` Oleg Nesterov
2011-11-01 18:27 ` Tejun Heo
2011-11-01 19:39 ` Oleg Nesterov
2011-11-01 19:46 ` Oleg Nesterov
2011-11-01 21:57 ` Tejun Heo
2011-11-02 11:42 ` Jeff Layton
2011-11-02 15:13 ` Oleg Nesterov
2011-11-02 16:23 ` Oleg Nesterov
2011-11-02 23:11 ` Rafael J. Wysocki
2011-11-03 11:15 ` Jeff Layton
2011-11-03 15:10 ` Oleg Nesterov
2011-11-02 17:53 ` [PATCH] wait_event_freezekillable: use freezer_do_not_count/freezer_count Oleg Nesterov
2011-11-03 10:42 ` Jeff Layton
2011-11-03 14:13 ` Tejun Heo
2011-11-03 15:27 ` Jeff Layton
2011-11-03 15:30 ` Tejun Heo
2011-11-01 18:26 ` [RFC PATCH] freezer: revert 27920651fe "PM / Freezer: Make fake_signal_wake_up() wake TASK_KILLABLE tasks too" Jeff Layton
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