From: Oleg Nesterov <oleg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Davide Libenzi <davidel@xmailserver.org>,
Eric Dumazet <eric.dumazet@gmail.com>, Greg KH <greg@kroah.com>,
Jason Baron <jbaron@redhat.com>,
Roland McGrath <roland@hack.frob.com>,
Eugene Teo <eugeneteo@kernel.sg>,
Maxime Bizon <mbizon@freebox.fr>,
Denys Vlasenko <dvlasenk@redhat.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 0/2] signalfd/epoll fixes
Date: Fri, 24 Feb 2012 20:06:51 +0100 [thread overview]
Message-ID: <20120224190651.GA22287@redhat.com> (raw)
In-Reply-To: <CA+55aFyaPY9xsDGDx0QqRR2gV_z541w_xXeQbh5Uknd26cvXCw@mail.gmail.com>
On 02/23, Linus Torvalds wrote:
>
> On Thu, Feb 23, 2012 at 7:44 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> >
> > Or we can rely on the fact that sighand_cachep is SLAB_DESTROY_BY_RCU,
> > and assume that ->whead is always rcu-protected if it can go away.
> >
> > In this case we don't need 3/4 (although it makes sense to add the
> > fat comment), and 4/4 can be simplified, see below.
>
> Ok.
>
> Can you also get rid of 1/4, because quite frankly, adding that
> BUG_ON() is just annoying. Either the thing gets fixed or not, but at
> no point is it ok to say "ok, I'm going to fix it, but before I do
> I'll just make it much worse".
OK. Please see v2.
Other changes:
- some comments
- now that we rely on rcu, ep_poll_callback() can do
remove_wait_queue() outsife of ep->lock
Davide, I see the new email, but it is too late for me to reply
today. Anyway, I think it makes sense to make the "simple" fix
before anything else. IOW, I'd suggest these changes for now in
any case (unless, of course, you see some problems).
Oleg.
next prev parent reply other threads:[~2012-02-24 19:13 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20120222173326.GA7139@redhat.com>
2012-02-22 17:33 ` [PATCH 1/4] signalfd: introduce signalfd_cleanup() Oleg Nesterov
2012-02-22 17:34 ` [PATCH 2/4] epoll: introduce POLLFREE for ep_poll_callback() Oleg Nesterov
2012-02-22 17:34 ` [PATCH 3/4] signalfd: signalfd_cleanup() can race with remove_wait_queue() Oleg Nesterov
2012-02-22 17:35 ` [PATCH 4/4] epoll: ep_unregister_pollwait() can use the freed pwq->whead Oleg Nesterov
2012-02-23 15:44 ` Oleg Nesterov
2012-02-23 22:17 ` Linus Torvalds
2012-02-24 19:06 ` Oleg Nesterov [this message]
2012-02-24 19:07 ` [PATCH v2 1/2] epoll: introduce POLLFREE to flush ->signalfd_wqh before kfree() Oleg Nesterov
2012-02-29 19:57 ` Andy Lutomirski
2012-02-29 20:06 ` Oleg Nesterov
2012-02-29 20:16 ` Andrew Lutomirski
2012-03-01 19:26 ` Oleg Nesterov
2012-02-24 19:07 ` [PATCH v2 2/2] epoll: ep_unregister_pollwait() can use the freed pwq->whead Oleg Nesterov
2012-02-24 20:23 ` [PATCH v2 0/2] signalfd/epoll fixes Linus Torvalds
2012-02-24 23:14 ` Linus Torvalds
2012-02-25 16:08 ` Oleg Nesterov
2012-02-25 19:00 ` Linus Torvalds
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