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author | 2005-10-30 14:59:54 -0800 | |
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committer | 2005-10-30 17:37:14 -0800 | |
commit | c32b6b8e524d2c337767d312814484d9289550cf (patch) | |
tree | 02e634b0b48db6eccc8774369366daa1893921ea /kernel/cpu.c | |
parent | [PATCH] Remove cpu_sys_devices in cpufreq subsystem. (diff) | |
download | linux-c32b6b8e524d2c337767d312814484d9289550cf.tar.gz linux-c32b6b8e524d2c337767d312814484d9289550cf.tar.bz2 linux-c32b6b8e524d2c337767d312814484d9289550cf.zip |
[PATCH] create and destroy cpufreq sysfs entries based on cpu notifiers
cpufreq entries in sysfs should only be populated when CPU is online state.
When we either boot with maxcpus=x and then boot the other cpus by echoing
to sysfs online file, these entries should be created and destroyed when
CPU_DEAD is notified. Same treatement as cache entries under sysfs.
We place the processor in the lowest frequency, so hw managed P-State
transitions can still work on the other threads to save power.
Primary goal was to just make these directories appear/disapper dynamically.
There is one in this patch i had to do, which i really dont like myself but
probably best if someone handling the cpufreq infrastructure could give
this code right treatment if this is not acceptable. I guess its probably
good for the first cut.
- Converting lock_cpu_hotplug()/unlock_cpu_hotplug() to disable/enable preempt.
The locking was smack in the middle of the notification path, when the
hotplug is already holding the lock. I tried another solution to avoid this
so avoid taking locks if we know we are from notification path. The solution
was getting very ugly and i decided this was probably good for this iteration
until someone who understands cpufreq could do a better job than me.
(akpm: export cpucontrol to GPL modules: drivers/cpufreq/cpufreq_stats.c now
does lock_cpu_hotplug())
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Dave Jones <davej@codemonkey.org.uk>
Cc: Zwane Mwaikambo <zwane@holomorphy.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r-- | kernel/cpu.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 53d8263ae12e..3619e939182e 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -17,6 +17,7 @@ /* This protects CPUs going up and down... */ DECLARE_MUTEX(cpucontrol); +EXPORT_SYMBOL_GPL(cpucontrol); static struct notifier_block *cpu_chain; |