Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH v0] add nano semaphore in kernel | Date | Wed, 29 Dec 2010 12:47:27 +0100 |
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On Tuesday 28 December 2010 16:51:30 Daniel Walker wrote: > We for sure don't want new semaphores, or new semaphore usage in the > kernel ..
Yes. I once even tried unifying the semaphore and rwsem implementation, but gave up on that for a number of reasons.
> It should also be noted that the rtmutex (kernel/rtmutex.c) already has > this capability. Although I don't think you can use an rtmutex from > inside the kernel.
I wasn't aware we had already grown another one ;-)
AFAICT, you can only use it inside of the kernel, but it's very specific and I wouldn't recommend using it unless a regular mutex cannot be used for some reason. The only user besides the futex code seems to be the i2c layer at this moment.
> If you really want this you should look into the rtmutex, and the > regular mutex API's .
If Hillf relies on counting semaphores, that won't work, but very few such users exist in code outside of textbooks.
Arnd
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