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authorAshok Raj <ashok.raj@intel.com>2005-11-28 13:43:46 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-28 14:42:23 -0800
commita9d9baa1e819b2f92f9cfa5240f766c535e636a6 (patch)
tree0ae15e5b1071b395affa0ac9abf6fd746ad60b0e /include/linux
parente0f39591cc178026607fcbbe9a53be435fe8285d (diff)
[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 'include/linux')
-rw-r--r--include/linux/cpu.h7
-rw-r--r--include/linux/sched.h1
2 files changed, 3 insertions, 5 deletions
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
index 43c44530ef9..0ed1d4853c6 100644
--- a/include/linux/cpu.h
+++ b/include/linux/cpu.h
@@ -65,10 +65,9 @@ extern struct sysdev_class cpu_sysdev_class;
#ifdef CONFIG_HOTPLUG_CPU
/* Stop CPUs going up and down. */
-extern struct semaphore cpucontrol;
-#define lock_cpu_hotplug() down(&cpucontrol)
-#define unlock_cpu_hotplug() up(&cpucontrol)
-#define lock_cpu_hotplug_interruptible() down_interruptible(&cpucontrol)
+extern void lock_cpu_hotplug(void);
+extern void unlock_cpu_hotplug(void);
+extern int lock_cpu_hotplug_interruptible(void);
#define hotcpu_notifier(fn, pri) { \
static struct notifier_block fn##_nb = \
{ .notifier_call = fn, .priority = pri }; \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2038bd27b04..b0ad6f30679 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -908,7 +908,6 @@ do { if (atomic_dec_and_test(&(tsk)->usage)) __put_task_struct(tsk); } while(0)
#define PF_SYNCWRITE 0x00200000 /* I am doing a sync write */
#define PF_BORROWED_MM 0x00400000 /* I am a kthread doing use_mm */
#define PF_RANDOMIZE 0x00800000 /* randomize virtual address space */
-#define PF_HOTPLUG_CPU 0x01000000 /* Currently performing CPU hotplug */
/*
* Only the _current_ task can read/write to tsk->flags, but other