Messages in this thread | | | Date | Tue, 29 May 2012 13:32:09 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: [RFC PATCH 00/10] Cleanup ipi_call_lock[_irq]()/ipi_call_unlock[_irq]() |
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On 05/29/2012 12:45 PM, Yong Zhang wrote:
> As discussed with Srivatsa [1], it seems there is no need to keep > ipi_call_[un]lock_irq() when cpu bring-up/down. Because: > > 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. > > In short it's more likely that keeping ipi_call_[un]lock() is leftover > before we introduce generic smp helper. This patchset is just to clean > things up. > > [1] http://marc.info/?l=linux-kernel&m=133766786814484&w=2 > > Yong Zhang (10): > hexagon: smp: remove call to ipi_call_lock()/ipi_call_unlock() > mn10300: smp: remove call to ipi_call_lock()/ipi_call_unlock() > parisc: smp: remove call to ipi_call_lock()/ipi_call_unlock() > S390: smp: remove call to ipi_call_lock()/ipi_call_unlock() > tile: smp: remove call to ipi_call_lock()/ipi_call_unlock() > x86: smp: remove call to ipi_call_lock()/ipi_call_unlock() > ia64: smp: remove call to ipi_call_lock_irq()/ipi_call_unlock_irq() > SPARC: smp: remove call to ipi_call_lock_irq()/ipi_call_unlock_irq() > POWERPC: smp: remove call to ipi_call_lock()/ipi_call_unlock() > smp: remove ipi_call_lock[_irq]()/ipi_call_unlock[_irq]() >
All patches except the sparc one look good. Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Regards, Srivatsa S. Bhat
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