On 4/18/2013 2:40 AM, Thomas Gleixner wrote:
On Wed, 10 Apr 2013, Michael Bohan wrote:
When switching to a new cpu_base in switch_hrtimer_base(), we
briefly enable preemption by unlocking the cpu_base lock in two
places. During this interval it's possible for the running thread
to be swapped to a different CPU.
Consider the following example:
CPU #0 CPU #1
---- ----
hrtimer_start() ...
lock_hrtimer_base()
switch_hrtimer_base()
this_cpu = 0;
target_cpu_base = 0;
raw_spin_unlock(&cpu_base->lock)
<migrate to CPU 1>
Errm. switch_hrtimer_base() is called with interrupts disabled and
they stay disabled, so how exactly is the task going to be migrated?
My mistake - I missed that important fact. Please disregard this.
Thanks,
Mike
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