From: Peter Zijlstra <peterz@infradead.org>
To: "Reshetova, Elena" <elena.reshetova@intel.com>
Cc: David Windsor <dwindsor@gmail.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Kees Cook <keescook@chromium.org>,
Greg KH <gregkh@linuxfoundation.org>,
Will Deacon <will.deacon@arm.com>, Arnd Bergmann <arnd@arndb.de>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
LKML <linux-kernel@vger.kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Subject: Re: [RFC][PATCH 2/7] kref: Add kref_read()
Date: Mon, 21 Nov 2016 17:00:59 +0100 [thread overview]
Message-ID: <20161121160059.GB3174@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20161121154915.GB3124@twins.programming.kicks-ass.net>
On Mon, Nov 21, 2016 at 04:49:15PM +0100, Peter Zijlstra wrote:
> > Speaking of non-fitting patterns. This one is quite common in
> > networking code for refcounters:
> >
> > if (atomic_cmpxchg(&cur->refcnt, 1, 0) == 1) {} This is from
> > net/netfilter/nfnetlink_acct.c, but there are similar ones in other
> > places.
>
> Cute, but weird it doesn't actually decrement if not 1.
Hurgh.. creative refcounting that. The question is how much of that do
we want to support? It really must not decrement there.
next prev parent reply other threads:[~2016-11-21 16:01 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-16 20:08 Alexei Starovoitov
2016-11-17 8:53 ` Peter Zijlstra
2016-11-17 16:19 ` Alexei Starovoitov
2016-11-17 16:34 ` Thomas Gleixner
2016-11-18 17:33 ` Reshetova, Elena
2016-11-19 3:47 ` Alexei Starovoitov
2016-11-21 8:18 ` Reshetova, Elena
2016-11-21 12:47 ` David Windsor
2016-11-21 15:39 ` Reshetova, Elena
2016-11-21 15:49 ` Peter Zijlstra
2016-11-21 16:00 ` Peter Zijlstra [this message]
2016-11-21 19:27 ` Reshetova, Elena
2016-11-21 20:12 ` David Windsor
2016-11-22 10:37 ` Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2016-11-14 17:39 [RFC][PATCH 0/7] kref improvements Peter Zijlstra
2016-11-14 17:39 ` [RFC][PATCH 2/7] kref: Add kref_read() Peter Zijlstra
2016-11-14 18:16 ` Christoph Hellwig
2016-11-15 7:28 ` Greg KH
2016-11-15 7:47 ` Peter Zijlstra
2016-11-15 7:33 ` Greg KH
2016-11-15 8:03 ` Peter Zijlstra
2016-11-15 20:53 ` Kees Cook
2016-11-16 8:21 ` Greg KH
2016-11-16 10:10 ` Peter Zijlstra
2016-11-16 10:18 ` Greg KH
2016-11-16 10:11 ` Daniel Borkmann
2016-11-16 10:19 ` Greg KH
2016-11-16 10:09 ` Peter Zijlstra
2016-11-16 18:58 ` Kees Cook
2016-11-17 8:34 ` Peter Zijlstra
2016-11-17 12:30 ` David Windsor
2016-11-17 12:43 ` Peter Zijlstra
2016-11-17 13:01 ` Reshetova, Elena
2016-11-17 13:22 ` Peter Zijlstra
2016-11-17 15:42 ` Reshetova, Elena
2016-11-17 18:02 ` Reshetova, Elena
2016-11-17 19:10 ` Peter Zijlstra
2016-11-17 19:29 ` Peter Zijlstra
2016-11-17 19:34 ` Kees Cook
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