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From: Oleg Nesterov <oleg@redhat.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: "Linus Torvalds" <torvalds@linux-foundation.org>,
	"Eric Dumazet" <eric.dumazet@gmail.com>,
	"Al Viro" <viro@zeniv.linux.org.uk>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Maciej Żenczykowski" <maze@google.com>
Subject: Re: [PATCH] task_work: remove fifo ordering guarantee
Date: Sat, 29 Aug 2015 14:54:21 +0200	[thread overview]
Message-ID: <20150829125421.GB14973@redhat.com> (raw)
In-Reply-To: <20150829092219.GA8916@gmail.com>

On 08/29, Ingo Molnar wrote:
>
> So I'm wondering, is there any strong reason why we couldn't use a double linked
> list and still do FIFO and remove that silly linear list walking hack?

This will obviously enlarge callback_head, and it is often embedded.
But this is minor.

If we use a double linked list we can't do task_work_add() lockless.
So we will need another spinlock_t in task_struct. We can't use pi_lock.

Oleg.


  reply	other threads:[~2015-08-29 12:56 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-29  2:42 [PATCH] task_work: remove fifo ordering guarantee Eric Dumazet
2015-08-29  3:19 ` Linus Torvalds
2015-08-29  9:22   ` Ingo Molnar
2015-08-29 12:54     ` Oleg Nesterov [this message]
2015-08-31  6:02       ` Ingo Molnar
2015-08-31 12:51         ` Oleg Nesterov
2015-08-29 12:49 ` Oleg Nesterov
2015-08-29 13:57   ` Eric Dumazet
2015-08-29 14:11     ` Eric Dumazet
2015-08-29 17:08       ` Linus Torvalds
2015-08-31  5:22         ` yalin wang
2015-09-05  5:19           ` Al Viro
2015-08-31 12:44         ` Oleg Nesterov
2015-09-05  5:12         ` Al Viro
2015-09-05  5:42           ` Al Viro
2015-09-05 20:46             ` Linus Torvalds
2015-08-31 12:05     ` change filp_close() to use __fput_sync() ? (Was: [PATCH] task_work: remove fifo ordering guarantee) Oleg Nesterov
2015-09-05  5:35   ` [PATCH] task_work: remove fifo ordering guarantee Al Viro
2015-09-07 12:27     ` [PATCH?] fput: don't abuse task_work_add() too much Oleg Nesterov
2015-09-07 13:49       ` [PATCH? v2] " Oleg Nesterov
  -- strict thread matches above, loose matches on Subject: below --
2015-08-29 21:08 [PATCH] task_work: remove fifo ordering guarantee George Spelvin
2015-08-31 13:22 ` Oleg Nesterov
2015-08-31 15:21   ` George Spelvin

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