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From: Peter Zijlstra <peterz@infradead.org>
To: Jan Engelhardt <jengelh@medozas.de>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org, mingo@elte.hu,
	laijs@cn.fujitsu.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
	josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
	rostedt@goodmis.org, Valdis.Kletnieks@vt.edu,
	dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com,
	fweisbec@gmail.com, patches@linaro.org
Subject: Re: [PATCH RFC tip/core/rcu 5/6] rcu: Make __kfree_rcu() less dependent on compiler choices
Date: Thu, 26 Apr 2012 15:50:45 +0200	[thread overview]
Message-ID: <1335448245.13683.50.camel@twins> (raw)
In-Reply-To: <alpine.LNX.2.01.1204261526080.31482@frira.zrqbmnf.qr>

On Thu, 2012-04-26 at 15:29 +0200, Jan Engelhardt wrote:
> On Thursday 2012-04-26 14:48, Peter Zijlstra wrote:
> >On Mon, 2012-04-23 at 09:42 -0700, Paul E. McKenney wrote:
> >> Currently, __kfree_rcu() is implemented as an inline function, and
> >> contains a BUILD_BUG_ON() that malfunctions if __kfree_rcu() is compiled
> >> as an out-of-line function.  Unfortunately, there are compiler settings
> >> (e.g., -O0) that can result in __kfree_rcu() being compiled out of line,
> >> resulting in annoying build breakage.  This commit therefore converts
> >> both __kfree_rcu() and __is_kfree_rcu_offset() from inline functions to
> >> macros to prevent such misbehavior on the part of the compiler.
> >
> >The kernel very explicitly doesn't support being compiled with -O0, so
> >this is a non-issue, I think you can make it work if you add
> >-finline-functions.
> >
> >I'd drop this, either make the entire kernel compile or don't bother.
> 
> It was not originally meant to make the entire kernel compile with -O0,
> but only select modules/.c files.

Same problem, who cares about select modules/.c files? Why should they
have different rules?

> That, or __always_inline just does not always inline.

It does indeed not without -finline-functions.

  reply	other threads:[~2012-04-26 13:51 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-23 16:41 [PATCH RFC 0/6] Miscellaneous RCU fixes for 3.5 Paul E. McKenney
2012-04-23 16:42 ` [PATCH RFC tip/core/rcu 1/6] rcu: Stabilize use of num_online_cpus() for GP short circuit Paul E. McKenney
2012-04-23 16:42   ` [PATCH RFC tip/core/rcu 2/6] rcu: List-debug variants of rcu list routines Paul E. McKenney
2012-04-23 16:42   ` [PATCH RFC tip/core/rcu 3/6] rcu: Replace list_first_entry_rcu() with list_first_or_null_rcu() Paul E. McKenney
2012-04-23 16:42   ` [PATCH RFC tip/core/rcu 4/6] rcu: Clarify help text for RCU_BOOST_PRIO Paul E. McKenney
2012-04-26 12:46     ` Peter Zijlstra
2012-04-26 17:28       ` Paul E. McKenney
2012-04-23 16:42   ` [PATCH RFC tip/core/rcu 5/6] rcu: Make __kfree_rcu() less dependent on compiler choices Paul E. McKenney
2012-04-26 12:48     ` Peter Zijlstra
2012-04-26 13:29       ` Jan Engelhardt
2012-04-26 13:50         ` Peter Zijlstra [this message]
2012-04-23 16:42   ` [PATCH RFC tip/core/rcu 6/6] rcu: Reduce cache-miss initialization latencies for large systems Paul E. McKenney
2012-04-26 12:51     ` Peter Zijlstra
2012-04-26 14:12       ` Paul E. McKenney
2012-04-26 15:28         ` Peter Zijlstra
2012-04-26 16:15           ` Paul E. McKenney
2012-04-26 19:41             ` Peter Zijlstra
2012-04-26 19:47               ` Peter Zijlstra
2012-04-26 20:29                 ` Paul E. McKenney
2012-04-26 22:04                   ` Peter Zijlstra
2012-04-26 20:28               ` Paul E. McKenney
2012-04-26 22:01                 ` Peter Zijlstra
2012-04-27 14:17                   ` Paul E. McKenney
2012-04-27  4:36     ` Mike Galbraith
2012-04-27 15:15       ` Paul E. McKenney
2012-04-28  4:42         ` Mike Galbraith
2012-04-28 17:21           ` Paul E. McKenney
2012-04-29  3:54             ` Mike Galbraith
2012-04-24 15:35   ` [PATCH RFC tip/core/rcu 1/6] rcu: Stabilize use of num_online_cpus() for GP short circuit Srivatsa S. Bhat
2012-04-24 16:50     ` Paul E. McKenney
2012-04-24 17:46       ` Srivatsa S. Bhat
2012-05-07  3:47       ` Rusty Russell

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