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| author | Ashok Raj <ashok.raj@intel.com> | 2005-11-08 21:34:24 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-09 07:55:50 -0800 |
| commit | 90d45d17f3e68608ac7ba8fc3d7acce022a19c8e (patch) | |
| tree | 615b2f21c3e02e0ec901febd180014fed64a6a01 /include/linux/sched.h | |
| parent | 330d57fb98a916fa8e1363846540dd420e99499a (diff) | |
| download | linux-3.10-90d45d17f3e68608ac7ba8fc3d7acce022a19c8e.tar.gz linux-3.10-90d45d17f3e68608ac7ba8fc3d7acce022a19c8e.tar.bz2 linux-3.10-90d45d17f3e68608ac7ba8fc3d7acce022a19c8e.zip | |
[PATCH] cpu hotplug: fix locking in cpufreq drivers
When calling target drivers to set frequency, we take cpucontrol lock.
When we modified the code to accomodate CPU hotplug, there was an attempt
to take a double lock of cpucontrol leading to a deadlock. Since the
current thread context is already holding the cpucontrol lock, we dont need
to make another attempt to acquire it.
Now we leave a trace in current->flags indicating current thread already is
under cpucontrol lock held, so we dont attempt to do this another time.
Thanks to Andrew Morton for the beating:-)
From: Brice Goglin <Brice.Goglin@ens-lyon.org>
Build fix
(akpm: this patch is still unpleasant. Ashok continues to look for a cleaner
solution, doesn't he? ;))
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Brice Goglin <Brice.Goglin@ens-lyon.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 03b68a7b4b8..2bbf968b23d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -909,6 +909,7 @@ 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 |