| Message ID | 20120529082732.GA4250@zhy |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
On 05/29/2012 01:57 PM, Yong Zhang wrote: > On Tue, May 29, 2012 at 01:31:54PM +0530, Srivatsa S. Bhat wrote: >> This looks odd. IRQs must not have been enabled at this point. >> Just remove the call to local_irq_enable() that is found a few lines above >> this line and then you won't have to add this call to local_irq_disable(). > > Yeah, have thought about it. But because I was not sure there is > special need to enalbe irq that early (don't know much about sparc), > I decided to make minor change :) > > Since we have gotten confirmation from David, I'm sending out the > new version. Please check it. > > Thanks, > Yong > > --- > From: Yong Zhang <yong.zhang@windriver.com> > Date: Tue, 29 May 2012 12:56:08 +0800 > Subject: [UPDATED] [RFC PATCH 8/10] SPARC: smp: remove call to > ipi_call_lock_irq()/ipi_call_unlock_irq() > > 1) call_function.lock used in smp_call_function_many() is just to protect > call_function.queue and &data->refs, cpu_online_mask is outside of the > lock. And it's not necessary to protect cpu_online_mask, > because data->cpumask is pre-calculate and even if a cpu is brougt up > when calling arch_send_call_function_ipi_mask(), it's harmless because > validation test in generic_smp_call_function_interrupt() will take care > of it. > > 2) For cpu down issue, stop_machine() will guarantee that no concurrent > smp_call_fuction() is processing. > > And also delay irq enable to after set_cpu_online(). > > Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> > Cc: "David S. Miller" <davem@davemloft.net> > Cc: sparclinux@vger.kernel.org > --- Looks good. Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> > arch/sparc/kernel/smp_64.c | 7 +------ > 1 files changed, 1 insertions(+), 6 deletions(-) > > diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c > index f591598..781bcb1 100644 > --- a/arch/sparc/kernel/smp_64.c > +++ b/arch/sparc/kernel/smp_64.c > @@ -103,8 +103,6 @@ void __cpuinit smp_callin(void) > if (cheetah_pcache_forced_on) > cheetah_enable_pcache(); > > - local_irq_enable(); > - > callin_flag = 1; > __asm__ __volatile__("membar #Sync\n\t" > "flush %%g6" : : : "memory"); > @@ -124,9 +122,8 @@ void __cpuinit smp_callin(void) > while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) > rmb(); > > - ipi_call_lock_irq(); > set_cpu_online(cpuid, true); > - ipi_call_unlock_irq(); > + local_irq_enable(); > > /* idle thread is expected to have preempt disabled */ > preempt_disable(); > @@ -1308,9 +1305,7 @@ int __cpu_disable(void) > mdelay(1); > local_irq_disable(); > > - ipi_call_lock(); > set_cpu_online(cpu, false); > - ipi_call_unlock(); > > cpu_map_rebuild(); > -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
From: Yong Zhang <yong.zhang0@gmail.com> Date: Tue, 29 May 2012 16:27:33 +0800 > From: Yong Zhang <yong.zhang@windriver.com> > Date: Tue, 29 May 2012 12:56:08 +0800 > Subject: [UPDATED] [RFC PATCH 8/10] SPARC: smp: remove call to > ipi_call_lock_irq()/ipi_call_unlock_irq() > > 1) call_function.lock used in smp_call_function_many() is just to protect > call_function.queue and &data->refs, cpu_online_mask is outside of the > lock. And it's not necessary to protect cpu_online_mask, > because data->cpumask is pre-calculate and even if a cpu is brougt up > when calling arch_send_call_function_ipi_mask(), it's harmless because > validation test in generic_smp_call_function_interrupt() will take care > of it. > > 2) For cpu down issue, stop_machine() will guarantee that no concurrent > smp_call_fuction() is processing. > > And also delay irq enable to after set_cpu_online(). > > Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c index f591598..781bcb1 100644 --- a/arch/sparc/kernel/smp_64.c +++ b/arch/sparc/kernel/smp_64.c @@ -103,8 +103,6 @@ void __cpuinit smp_callin(void) if (cheetah_pcache_forced_on) cheetah_enable_pcache(); - local_irq_enable(); - callin_flag = 1; __asm__ __volatile__("membar #Sync\n\t" "flush %%g6" : : : "memory"); @@ -124,9 +122,8 @@ void __cpuinit smp_callin(void) while (!cpumask_test_cpu(cpuid, &smp_commenced_mask)) rmb(); - ipi_call_lock_irq(); set_cpu_online(cpuid, true); - ipi_call_unlock_irq(); + local_irq_enable(); /* idle thread is expected to have preempt disabled */ preempt_disable(); @@ -1308,9 +1305,7 @@ int __cpu_disable(void) mdelay(1); local_irq_disable(); - ipi_call_lock(); set_cpu_online(cpu, false); - ipi_call_unlock(); cpu_map_rebuild();