From: Rusty Russell <rusty@rustcorp.com.au>
To: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>,
linux-kernel@vger.kernel.org, Mel Gorman <mel@csn.ul.ie>,
Pekka Enberg <penberg@cs.helsinki.fi>,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: Re: [this_cpu_xx V7 7/8] Module handling: Use this_cpu_xx to dynamically allocate counters
Date: Wed, 16 Dec 2009 09:11:42 +1030 [thread overview]
Message-ID: <200912160911.43201.rusty@rustcorp.com.au> (raw)
In-Reply-To: <4B270AA6.3050307@kernel.org>
On Tue, 15 Dec 2009 02:33:50 pm Tejun Heo wrote:
> (Rusty Russell cc'd.)
>
> On 12/15/2009 07:03 AM, Christoph Lameter wrote:
> > @@ -479,15 +467,15 @@ static inline int try_module_get(struct
> > int ret = 1;
> >
> > if (module) {
> > - unsigned int cpu = get_cpu();
> > if (likely(module_is_live(module))) {
> > - local_inc(__module_ref_addr(module, cpu));
> > + preempt_disable();
> > + __this_cpu_inc(module->refptr->count);
> > trace_module_get(module, _THIS_IP_,
> > - local_read(__module_ref_addr(module, cpu)));
> > + __this_cpu_read(module->refptr->count));
> > + preempt_enable();
> > }
> > else
> > ret = 0;
> > - put_cpu();
>
> I think you need preemption disabled while checking whether
> module_is_live(). The state is protected by stop_machine or
> synchronize_sched().
Yes.
Thanks,
Rusty.
next prev parent reply other threads:[~2009-12-15 22:41 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-14 22:03 [this_cpu_xx V7 0/8] Per cpu atomics in core allocators and cleanup Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 1/8] this_cpu_ops: page allocator conversion Christoph Lameter
2009-12-15 3:53 ` Tejun Heo
2009-12-15 15:04 ` Christoph Lameter
2009-12-16 0:53 ` Tejun Heo
2009-12-16 14:55 ` Christoph Lameter
2009-12-17 0:23 ` Tejun Heo
2009-12-14 22:03 ` [this_cpu_xx V7 2/8] this_cpu ops: Remove pageset_notifier Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 3/8] Use this_cpu operations in slub Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 4/8] SLUB: Get rid of dynamic DMA kmalloc cache allocation Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 5/8] this_cpu: Remove slub kmem_cache fields Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 6/8] Make slub statistics use this_cpu_inc Christoph Lameter
2009-12-15 6:24 ` Eric Dumazet
2009-12-15 14:46 ` Christoph Lameter
2009-12-15 14:59 ` Eric Dumazet
2009-12-14 22:03 ` [this_cpu_xx V7 7/8] Module handling: Use this_cpu_xx to dynamically allocate counters Christoph Lameter
2009-12-15 4:03 ` Tejun Heo
2009-12-15 22:41 ` Rusty Russell [this message]
2009-12-16 16:10 ` Christoph Lameter
2009-12-17 0:25 ` Tejun Heo
2009-12-17 5:42 ` Rusty Russell
2009-12-14 22:03 ` [this_cpu_xx V7 8/8] Remove cpu_local_xx macros Christoph Lameter
2009-12-15 4:04 ` Tejun Heo
2009-12-15 6:37 ` [this_cpu_xx V7 0/8] Per cpu atomics in core allocators and cleanup Pekka Enberg
2009-12-15 6:47 ` Tejun Heo
2009-12-15 14:50 ` Christoph Lameter
2009-12-15 17:06 ` Mel Gorman
2009-12-16 14:44 ` Christoph Lameter
2009-12-16 21:36 ` Christoph Lameter
2009-12-15 17:43 ` Mathieu Desnoyers
2009-12-16 0:58 ` Tejun Heo
2009-12-16 1:40 ` Mathieu Desnoyers
2009-12-16 1:46 ` Tejun Heo
2009-12-17 13:39 ` Mathieu Desnoyers
2009-12-17 19:28 ` Christoph Lameter
2009-12-17 20:25 ` Mathieu Desnoyers
2009-12-17 20:43 ` Christoph Lameter
2009-12-18 0:13 ` Mathieu Desnoyers
2009-12-18 0:27 ` Christoph Lameter
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