linux-kernel - [PATCH v2 0/4] sched/wait: fix and then kill abort_exclusive

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Message-ID: <20160906140013.GA6139@redhat.com>
Date:   Tue, 6 Sep 2016 16:00:13 +0200
From:   Oleg Nesterov <oleg@...hat.com>
To:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Al Viro <viro@...IV.linux.org.uk>,
        Bart Van Assche <bvanassche@....org>,
        Johannes Weiner <hannes@...xchg.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Neil Brown <neilb@...e.de>, linux-kernel@...r.kernel.org
Subject: [PATCH v2 0/4] sched/wait: fix and then kill abort_exclusive_wait()

On 09/02, Peter Zijlstra wrote:
>
> On Fri, Sep 02, 2016 at 02:06:43PM +0200, Oleg Nesterov wrote:
>
> > And, if you agree with this change I will try to change __wait_event()
> > as well and kill abort_exclusive_wait().
>
> Yeah, I think this'll work. Please send a new series with 'enhanced'
> changelog so that when we have to look at this again in a few
> weeks/months time we won't be cursing at ourselves for how the heck it
> was supposed to work.

OK, thanks, please see V2.

I think it makes sense to change ___wait_event() first, this simplifies the
documentation in __wait_on_bit_lock().

See also 4/4, it is new and simple. From the changelog

	In particular we are ready to remove the signal_pending_state()
	checks from wait_bit_action_f helpers and change __wait_on_bit_lock()
	to use prepare_to_wait_event().

Yes. The necessary change is trivial. But this probably needs a separate
discussion/testing because we need to re-investigate the problem which was
somehow fixed by 68985633bccb60 "sched/wait: Fix signal handling in bit wait
helpers".

Oleg.

 include/linux/wait.h |  17 ++-------
 kernel/sched/wait.c  | 101 ++++++++++++++++++++++++---------------------------
 2 files changed, 52 insertions(+), 66 deletions(-)