diff options
author | Ashok Raj <ashok.raj@intel.com> | 2005-10-30 14:59:54 -0800 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-30 17:37:14 -0800 |
commit | c32b6b8e524d2c337767d312814484d9289550cf (patch) | |
tree | 02e634b0b48db6eccc8774369366daa1893921ea /drivers/cpufreq/cpufreq_stats.c | |
parent | d434fca737bee0862625c2377b987a7713b6b487 (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 'drivers/cpufreq/cpufreq_stats.c')
-rw-r--r-- | drivers/cpufreq/cpufreq_stats.c | 42 |
1 files changed, 38 insertions, 4 deletions
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c index 741b6b191e6a..3597f25d5efa 100644 --- a/drivers/cpufreq/cpufreq_stats.c +++ b/drivers/cpufreq/cpufreq_stats.c @@ -19,6 +19,7 @@ #include <linux/percpu.h> #include <linux/kobject.h> #include <linux/spinlock.h> +#include <linux/notifier.h> #include <asm/cputime.h> static spinlock_t cpufreq_stats_lock; @@ -298,6 +299,27 @@ cpufreq_stat_notifier_trans (struct notifier_block *nb, unsigned long val, return 0; } +static int __cpuinit cpufreq_stat_cpu_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) +{ + unsigned int cpu = (unsigned long)hcpu; + + switch (action) { + case CPU_ONLINE: + cpufreq_update_policy(cpu); + break; + case CPU_DEAD: + cpufreq_stats_free_table(cpu); + break; + } + return NOTIFY_OK; +} + +static struct notifier_block cpufreq_stat_cpu_notifier = +{ + .notifier_call = cpufreq_stat_cpu_callback, +}; + static struct notifier_block notifier_policy_block = { .notifier_call = cpufreq_stat_notifier_policy }; @@ -311,6 +333,7 @@ __init cpufreq_stats_init(void) { int ret; unsigned int cpu; + spin_lock_init(&cpufreq_stats_lock); if ((ret = cpufreq_register_notifier(¬ifier_policy_block, CPUFREQ_POLICY_NOTIFIER))) @@ -323,20 +346,31 @@ __init cpufreq_stats_init(void) return ret; } - for_each_cpu(cpu) - cpufreq_update_policy(cpu); + register_cpu_notifier(&cpufreq_stat_cpu_notifier); + lock_cpu_hotplug(); + for_each_online_cpu(cpu) { + cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_ONLINE, + (void *)(long)cpu); + } + unlock_cpu_hotplug(); return 0; } static void __exit cpufreq_stats_exit(void) { unsigned int cpu; + cpufreq_unregister_notifier(¬ifier_policy_block, CPUFREQ_POLICY_NOTIFIER); cpufreq_unregister_notifier(¬ifier_trans_block, CPUFREQ_TRANSITION_NOTIFIER); - for_each_cpu(cpu) - cpufreq_stats_free_table(cpu); + unregister_cpu_notifier(&cpufreq_stat_cpu_notifier); + lock_cpu_hotplug(); + for_each_online_cpu(cpu) { + cpufreq_stat_cpu_callback(&cpufreq_stat_cpu_notifier, CPU_DEAD, + (void *)(long)cpu); + } + unlock_cpu_hotplug(); } MODULE_AUTHOR ("Zou Nan hai <nanhai.zou@intel.com>"); |