Messages in this thread | | | Date | Mon, 21 May 2012 13:59:24 -0700 | From | Frank Rowand <> | Subject | Re: [PATCH RT 2/2] fix printk flush of messages |
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On 05/21/12 13:10, Venkat Subbiah wrote: > On 05/16/2012 06:09 PM, Frank Rowand wrote: >> Updates console-make-rt-friendly.patch >> >> #ifdef CONFIG_PREEMPT_RT_FULL, printk() output is never flushed by >> printk() because: > So this is an issue for printk() itself and is not just for early_printk()? > > > # some liberties taken in this pseudo-code to make it easier to follow > printk() > vprintk() > raw_spin_lock(&logbuf_lock) > # increment preempt_count(): > preempt_disable() > result = console_trylock_for_printk() > > As I read it console_trylock_for_printk() is called from printk() but in > code it is called from vprintk()
Yes, I goofed on the indentation, starting at console_trylock_for_printk(). It should have been:
# some liberties taken in this pseudo-code to make it easier to follow printk() vprintk() raw_spin_lock(&logbuf_lock) # increment preempt_count(): preempt_disable() result = console_trylock_for_printk() retval = 0 # lock will always be false, because preempt_count() will be >= 1 lock = ... && !preempt_count() if (lock) retval = 1 return retval # result will always be false since lock will always be false if (result) console_unlock() # this is where the printk() output would be flushed
Thanks,
Frank
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