Re: [PATCH RESEND v4] sched: fix llc shared map unreleased during cpu hotplug

[Mike Galbraith <umgwanakikbuti@gmail.com>]

Hm, this patchlet seems to be having trouble taking wing.

(tosses it up in the air.. flap yer little wings patchlet)

I thought you had changed the title to..

x86,cpu-hotplug: clear llc_shared_mask at CPU hotplug

..due to Peter saying sched is only a consumer, but v4 somehow reverted
back to being a sched patch.

On Mon, 2014-08-25 at 13:49 +0800, Wanpeng Li wrote: 
> [  220.262245] Call Trace:
> [  220.262252]  [<ffffffff810e8396>] load_balance+0x156/0x980
> [  220.262259]  [<ffffffff816eeffe>] ? _raw_spin_unlock_irqrestore+0x2e/0xa0
> [  220.262266]  [<ffffffff810e9aa3>] idle_balance+0xe3/0x150
> [  220.262270]  [<ffffffff816ec4e7>] __schedule+0x797/0x8d0
> [  220.262277]  [<ffffffff816ec934>] schedule+0x24/0x70
> [  220.262283]  [<ffffffff816e9cd9>] schedule_timeout+0x119/0x1f0
> [  220.262294]  [<ffffffff810bb6e0>] ? lock_timer_base+0x70/0x70
> [  220.262301]  [<ffffffff816e9dc9>] schedule_timeout_uninterruptible+0x19/0x20
> [  220.262308]  [<ffffffff810bd3e8>] msleep+0x18/0x20
> [  220.262317]  [<ffffffff813aa11a>] lock_device_hotplug_sysfs+0x2a/0x50
> [  220.262323]  [<ffffffff813aa16e>] online_store+0x2e/0x80
> [  220.262358]  [<ffffffff813a873b>] dev_attr_store+0x1b/0x20
> 
> Last level cache shared map is built during cpu up and build sched domain 
> routine takes advantage of it to setup sched domain cpu topology, however, 
> llc shared map is unreleased during cpu disable which lead to invalid sched 
> domain cpu topology. This patch fix it by release llc shared map correctly
> during cpu disable.
> 
> Reviewed-by: Toshi Kani <toshi.kani@hp.com>
> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
> Tested-by: Linn Crosetto <linn@hp.com>
> Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
> ---
> v3 -> v4:
>  * simplify backtrace
> v2 -> v3:
>  * simplify backtrace 
> v1 -> v2:
>  * fix subject line
> 
>  arch/x86/kernel/smpboot.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 5492798..0134ec7 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -1292,6 +1292,9 @@ static void remove_siblinginfo(int cpu)
>  
>  	for_each_cpu(sibling, cpu_sibling_mask(cpu))
>  		cpumask_clear_cpu(cpu, cpu_sibling_mask(sibling));
> +	for_each_cpu(sibling, cpu_llc_shared_mask(cpu))
> +		cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling));
> +	cpumask_clear(cpu_llc_shared_mask(cpu));
>  	cpumask_clear(cpu_sibling_mask(cpu));
>  	cpumask_clear(cpu_core_mask(cpu));
>  	c->phys_proc_id = 0;