lkml.org 
[lkml]   [2012]   [May]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Subject[RFC PATCH 00/10] Cleanup ipi_call_lock[_irq]()/ipi_call_unlock[_irq]()
Date
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]()

arch/hexagon/kernel/smp.c | 2 --
arch/ia64/kernel/smpboot.c | 2 --
arch/mn10300/kernel/smp.c | 2 --
arch/parisc/kernel/smp.c | 2 --
arch/powerpc/kernel/smp.c | 2 --
arch/s390/kernel/smp.c | 2 --
arch/sparc/kernel/smp_64.c | 6 ++----
arch/tile/kernel/smpboot.c | 10 ----------
arch/x86/kernel/smpboot.c | 9 ---------
arch/x86/xen/smp.c | 2 --
include/linux/smp.h | 4 ----
kernel/smp.c | 20 --------------------
12 files changed, 2 insertions(+), 61 deletions(-)
--
1.7.5.4



\
 
 \ /
  Last update: 2012-05-29 10:01    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site