linux/arch/x86/kernel/cpu
Linus Torvalds ea34f43a07 acpi-cpufreq: fix 'smp_call_function_many()' confusion
It turns out that 'smp_call_function_many()' doesn't work at all like
'smp_call_function_single()', and my change to Andrew's patch to use it
rather than a loop over all CPU's acpi-cpufreq doesn't work.

My bad.

'smp_call_function_many()' has two "features" (aka "documented bugs"):

 (a) it needs to be called with preemption disabled, because it uses
     smp_processor_id() without guarding the CPU lookup with 'get_cpu()'
     and 'put_cpu()' like the 'single' variant does.

 (b) even if the current CPU is part of the CPU mask, it won't do the
     call on that CPU.

Still, we're better off trying to use 'smp_call_function_many()' than
looping over CPU's, since it at least in theory allows us to use a
broadcast IPI and do it all in parallel.  So let's just work around the
silly semantic bugs in that function.

Reported-and-tested-by: Ali Gholami Rudi <ali@rudi.ir>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-15 08:41:16 -07:00
..
cpufreq acpi-cpufreq: fix 'smp_call_function_many()' confusion 2009-04-15 08:41:16 -07:00
mcheck Merge branch 'linus' into cpumask-for-linus 2009-03-30 23:53:32 +02:00
mtrr x86, mtrr: remove debug message 2009-04-04 00:31:02 +02:00
.gitignore Update .gitignore files for generated targets 2008-10-20 11:24:31 -07:00
addon_cpuid_features.c x86 ACPI: Add support for Always Running APIC timer 2009-04-07 18:17:51 -04:00
amd.c x86: move various CPU initialization objects into .cpuinit.rodata 2009-03-12 13:13:07 +01:00
bugs_64.c x86: move bugs_64.c to cpu/bugs_64.c 2008-06-03 14:43:00 -07:00
bugs.c x86: fdiv bug detection fix 2008-07-31 23:56:27 +02:00
centaur.c x86/centaur: merge 32 & 64 bit version 2009-03-14 16:27:29 +01:00
cmpxchg.c x86: move cmpxchg fallbacks to a generic place 2008-08-18 16:05:47 +02:00
common.c Merge branch 'linus' into cpumask-for-linus 2009-03-30 23:53:32 +02:00
cpu_debug.c x86: cpu_debug remove execute permission 2009-04-09 06:34:02 +02:00
cpu.h x86: cpu/cpu.h cleanup 2009-03-23 02:06:51 +05:30
cyrix.c x86: move various CPU initialization objects into .cpuinit.rodata 2009-03-12 13:13:07 +01:00
hypervisor.c x86: hypervisor - fix sparse warnings 2008-11-23 11:11:52 +01:00
intel_cacheinfo.c Merge branch 'linus' into cpumask-for-linus 2009-03-30 23:53:32 +02:00
intel.c Merge branch 'linus' into x86/core 2009-03-28 22:27:45 +01:00
Makefile x86/centaur: merge 32 & 64 bit version 2009-03-14 16:27:29 +01:00
mkcapflags.pl x86: generate names for /proc/cpuinfo from <asm/cpufeature.h> 2008-08-27 19:23:22 -07:00
perfctr-watchdog.c x86: fold apic_ops into genapic 2009-02-17 12:22:20 +01:00
powerflags.c x86: generate names for /proc/cpuinfo from <asm/cpufeature.h> 2008-08-27 19:23:22 -07:00
proc.c cpumask: use new cpumask functions throughout x86 2009-03-13 14:49:54 +10:30
transmeta.c x86: move various CPU initialization objects into .cpuinit.rodata 2009-03-12 13:13:07 +01:00
umc.c x86: move various CPU initialization objects into .cpuinit.rodata 2009-03-12 13:13:07 +01:00
vmware.c x86: vmware - fix sparse warnings 2008-11-23 11:02:36 +01:00