diff options
author | Ashok Raj <ashok.raj@intel.com> | 2005-11-28 21:43:46 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-28 22:42:23 (GMT) |
commit | a9d9baa1e819b2f92f9cfa5240f766c535e636a6 (patch) | |
tree | 0ae15e5b1071b395affa0ac9abf6fd746ad60b0e /drivers | |
parent | e0f39591cc178026607fcbbe9a53be435fe8285d (diff) | |
download | linux-fsl-qoriq-a9d9baa1e819b2f92f9cfa5240f766c535e636a6.tar.xz |
[PATCH] clean up lock_cpu_hotplug() in cpufreq
There are some callers in cpufreq hotplug notify path that the lowest
function calls lock_cpu_hotplug(). The lock is already held during
cpu_up() and cpu_down() calls when the notify calls are broadcast to
registered clients.
Ideally if possible, we could disable_preempt() at the highest caller and
make sure we dont sleep in the path down in cpufreq->driver_target() calls
but the calls are so intertwined and cumbersome to cleanup.
Hence we consistently use lock_cpu_hotplug() and unlock_cpu_hotplug() in
all places.
- Removed export of cpucontrol semaphore and made it static.
- removed explicit uses of up/down with lock_cpu_hotplug()
so we can keep track of the the callers in same thread context and
just keep refcounts without calling a down() that causes a deadlock.
- Removed current_in_hotplug() uses
- Removed PF_HOTPLUG_CPU in sched.h introduced for the current_in_hotplug()
temporary workaround.
Tested with insmod of cpufreq_stat.ko, and logical online/offline
to make sure we dont have any hang situations.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Cc: Zwane Mwaikambo <zwane@linuxpower.ca>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/cpufreq/cpufreq.c | 12 |
1 files changed, 2 insertions, 10 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 1c0f62d..815902c 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -1113,21 +1113,13 @@ int __cpufreq_driver_target(struct cpufreq_policy *policy, { int retval = -EINVAL; - /* - * If we are already in context of hotplug thread, we dont need to - * acquire the hotplug lock. Otherwise acquire cpucontrol to prevent - * hotplug from removing this cpu that we are working on. - */ - if (!current_in_cpu_hotplug()) - lock_cpu_hotplug(); - + lock_cpu_hotplug(); dprintk("target for CPU %u: %u kHz, relation %u\n", policy->cpu, target_freq, relation); if (cpu_online(policy->cpu) && cpufreq_driver->target) retval = cpufreq_driver->target(policy, target_freq, relation); - if (!current_in_cpu_hotplug()) - unlock_cpu_hotplug(); + unlock_cpu_hotplug(); return retval; } |