From c32b6b8e524d2c337767d312814484d9289550cf Mon Sep 17 00:00:00 2001 From: Ashok Raj Date: Sun, 30 Oct 2005 14:59:54 -0800 Subject: [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 Signed-off-by: Venkatesh Pallipadi Cc: Dave Jones Cc: Zwane Mwaikambo Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/cpu.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/cpu.c') 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; -- cgit v1.2.3