kernel_optimize_test/arch/powerpc
Gautham R Shenoy 51badebdcf powerpc/pseries: Serialize cpu hotplug operations during deactivate Vs deallocate
Currently the cpu-allocation/deallocation process comprises of two steps:
- Set the indicators and to update the device tree with DLPAR node
  information.

- Online/offline the allocated/deallocated CPU.

This is achieved by writing to the sysfs tunables "probe" during allocation
and "release" during deallocation.

At the sametime, the userspace can independently online/offline the CPUs of
the system using the sysfs tunable "online".

It is quite possible that when a userspace tool offlines a CPU
for the purpose of deallocation and is in the process of updating the device
tree, some other userspace tool could bring the CPU back online by writing to
the "online" sysfs tunable thereby causing the deallocate process to fail.

The solution to this is to serialize writes to the "probe/release" sysfs
tunable with the writes to the "online" sysfs tunable.

This patch employs a mutex to provide this serialization, which is a no-op on
all architectures except PPC_PSERIES

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Acked-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-12-09 17:09:36 +11:00
..
boot Merge commit 'origin/master' into next 2009-11-24 17:16:30 +11:00
configs powerpc/86xx: Support for NVRAM on GE Fanuc's PPC9A 2009-11-20 16:45:37 -06:00
include/asm sysfs/cpu: Add probe/release files 2009-12-09 17:09:33 +11:00
kernel powerpc: stop_this_cpu: remove the cpu from the online map. 2009-12-09 17:09:34 +11:00
kvm powerpc/kvm: Sync guest visible MMU state 2009-12-08 16:02:50 +11:00
lib powerpc: Add configurable -Werror for arch/powerpc 2009-06-16 14:15:45 +10:00
math-emu
mm powerpc/mm: Fix pgtable cache cleanup with CONFIG_PPC_SUBPAGE_PROT 2009-12-08 15:59:33 +11:00
oprofile powerpc: Remove unnecessary semicolons 2009-07-08 13:50:21 +10:00
platforms powerpc/pseries: Serialize cpu hotplug operations during deactivate Vs deallocate 2009-12-09 17:09:36 +11:00
sysdev powerpc: Fixup last users of irq_chip->typename 2009-11-24 14:32:45 +11:00
xmon powerpc/pseries: Add extended_cede_processor() helper function. 2009-11-24 14:33:03 +11:00
Kconfig sysfs/cpu: Add probe/release files 2009-12-09 17:09:33 +11:00
Kconfig.debug powerpc: Add configurable -Werror for arch/powerpc 2009-06-16 14:15:45 +10:00
Makefile powerpc: Check for unsupported relocs when using CONFIG_RELOCATABLE 2009-09-24 15:31:40 +10:00
relocs_check.pl powerpc: Check for unsupported relocs when using CONFIG_RELOCATABLE 2009-09-24 15:31:40 +10:00