On 01/29, Christoph Lameter wrote: > > On Tue, 30 Jan 2007, Oleg Nesterov wrote: > > > Now we have 2 additional events, CPU_LOCK_ACQUIRE/CPU_LOCK_RELEASE, > > so cpuup_callback() can use them to lock/unlock cache_chain_mutex, > > but this is not related. > > Then we wont need to do the mutex_lock/unlock in CPU_DOWN_XX > anymore, right? Which brings us to this form of the patch:
Yes, if CPU_LOCK_ACQUIRE takes cache_chain_mutex, we don't need to do so on CPU_DOWN_PREPARE. I didn't know cpuup_callback() was already converted, sorry for the confusion! Note: with the patch below we are doing cancel_rearming_delayed_work() under cache_chain_mutex. This is ok since cache_reap() does mutex_trylock(), so deadlock is not possible. However, this means that mutex_trylock() becomes mandatory for cache_reap(), probably a little comment will be good. > Shutdown cache_reaper when cpu goes down > > Shutdown the cache_reaper in slab.c if the cpu is brought down > and set the cache_reap.func to NULL. Otherwise hotplug shuts > down the reaper for good. > > Signed-off-by: Christoph Lameter <[EMAIL PROTECTED]> > > Index: linux-2.6.20-rc6-mm2/mm/slab.c > =================================================================== > --- linux-2.6.20-rc6-mm2.orig/mm/slab.c 2007-01-29 14:27:34.199229828 > -0600 > +++ linux-2.6.20-rc6-mm2/mm/slab.c 2007-01-29 15:47:18.293962726 -0600 > @@ -1271,6 +1271,14 @@ static int __cpuinit cpuup_callback(stru > start_cpu_timer(cpu); > break; > #ifdef CONFIG_HOTPLUG_CPU > + case CPU_DOWN_PREPARE: > + /* Shutdown cache reaper */ > + cancel_rearming_delayed_work(&per_cpu(reap_work, cpu)); > + per_cpu(reap_work, cpu).work.func = NULL; > + break; > + case CPU_DOWN_FAILED: > + start_cpu_timer(cpu); > + break; > case CPU_DEAD: > /* > * Even if all the cpus of a node are down, we don't free the - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
