* Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > On Wed, 2011-06-08 at 21:17 +0200, Ingo Molnar wrote: > > Hm, the no-wakeup aspect seems rather useful. > > > > Could we perhaps remove console_sem and replace it with a mutex and > > do something like this with a mutex and its ->wait_lock? > > > > We'd have two happy side effects: > > > > - we'd thus remove one of the last core kernel semaphore users > > - we'd gain lockdep coverage for console locking as a bonus ... > > The mutex thing is more complex due to the mutex fast path, the > advantage of the semaphore is its simple implementation that always > takes the internal lock. > > I guess I can make it happen, but its a tad more tricky. Hm, i thought it would be possible to only express it via the slowpath: if mutex_trylock() succeeds then *all* execution goes into the slowpath so we don't have to take all the fastpaths into account. If that's notpossible then i think you and Linus are right that it's not worth creating all the per arch fastpath special cases for something like this. The non-removal of the console_sem is sad though. Sniff. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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