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authorAlexey Dobriyan <adobriyan@openvz.org>2007-02-16 04:48:11 -0500
committerDave Jones <davej@redhat.com>2007-02-20 14:23:43 -0500
commitb077ffb3b767c3efb44d00b998385a9cb127255c (patch)
tree160369b5541142afedc20a97a9c89718550cf2a3 /arch/x86_64/lib
parent22f7bb0329a506f2fd61c14ce3c8bc632e08c732 (diff)
rdmsr_on_cpu, wrmsr_on_cpu
There was OpenVZ specific bug rendering some cpufreq drivers unusable on SMP. In short, when cpufreq code thinks it confined itself to needed cpu by means of set_cpus_allowed() to execute rdmsr, some "virtual cpu" feature can migrate process to anywhere. This triggers bugons and does wrong things in general. This got fixed by introducing rdmsr_on_cpu and wrmsr_on_cpu executing rdmsr and wrmsr on given physical cpu by means of smp_call_function_single(). Dave Jones mentioned cpufreq might be not only user of rdmsr_on_cpu() and wrmsr_on_cpu(), so I'm putting them into arch/{i386,x86_64}/lib/ . Signed-off-by: Alexey Dobriyan <adobriyan@openvz.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'arch/x86_64/lib')
-rw-r--r--arch/x86_64/lib/Makefile2
-rw-r--r--arch/x86_64/lib/msr-on-cpu.c1
2 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86_64/lib/Makefile b/arch/x86_64/lib/Makefile
index b78d4170fce2..0a43f07b0290 100644
--- a/arch/x86_64/lib/Makefile
+++ b/arch/x86_64/lib/Makefile
@@ -4,7 +4,7 @@
4 4
5CFLAGS_csum-partial.o := -funroll-loops 5CFLAGS_csum-partial.o := -funroll-loops
6 6
7obj-y := io.o iomap_copy.o 7obj-y := io.o iomap_copy.o msr-on-cpu.o
8 8
9lib-y := csum-partial.o csum-copy.o csum-wrappers.o delay.o \ 9lib-y := csum-partial.o csum-copy.o csum-wrappers.o delay.o \
10 usercopy.o getuser.o putuser.o \ 10 usercopy.o getuser.o putuser.o \
diff --git a/arch/x86_64/lib/msr-on-cpu.c b/arch/x86_64/lib/msr-on-cpu.c
new file mode 100644
index 000000000000..47e0ec47c376
--- /dev/null
+++ b/arch/x86_64/lib/msr-on-cpu.c
@@ -0,0 +1 @@
#include "../../i386/lib/msr-on-cpu.c"