Messages in this thread | | | Date | Fri, 22 Feb 2008 17:20:53 -0500 | From | Gregory Haskins <> | Subject | Re: [PATCH [RT] 11/14] optimize the !printk fastpath through the lock acquisition |
| |
Pavel Machek wrote: > Hi! > >> Decorate the printk path with an "unlikely()" >> >> Signed-off-by: Gregory Haskins <ghaskins@novell.com> >> --- >> >> kernel/rtmutex.c | 8 ++++---- >> 1 files changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c >> index 122f143..ebdaa17 100644 >> --- a/kernel/rtmutex.c >> +++ b/kernel/rtmutex.c >> @@ -660,12 +660,12 @@ rt_spin_lock_fastlock(struct rt_mutex *lock, >> void fastcall (*slowfn)(struct rt_mutex *lock)) >> { >> /* Temporary HACK! */ >> - if (!current->in_printk) >> - might_sleep(); >> - else if (in_atomic() || irqs_disabled()) >> + if (unlikely(current->in_printk) && (in_atomic() || irqs_disabled())) >> /* don't grab locks for printk in atomic */ >> return; >> >> + might_sleep(); > > I think you changed the code here... you call might_sleep() in > different cases afaict.
Agreed, but it's still correct afaict. I added an extra might_sleep() to a path that really might sleep. I should have mentioned that in the header.
In any case, its moot. Andi indicated this patch is probably a no-op so I was considering dropping it on the v2 pass.
Regards, -Greg
| |