Messages in this thread | | | Date | Tue, 3 Jan 2006 16:42:44 +0100 | From | Ingo Molnar <> | Subject | Re: [patch 08/19] mutex subsystem, core |
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* Linus Torvalds <torvalds@osdl.org> wrote:
> On Tue, 3 Jan 2006, Ingo Molnar wrote: > > > > > > Is this an interrupt deadlock, or do you not allow interrupt contexts > > > to even trylock a mutex? > > > > correct, no irq contexts are allowed. This is also checked for if > > CONFIG_DEBUG_MUTEXES is enabled. > > Note that semaphores are definitely used from interrupt context, and > as such you can't replace them with mutexes if you do this. > > The prime example is the console semaphore. See kernel/printk.c, look > for "down_trylock()", and realize that they are all about interrupts.
yeah, i know - and i'm not trying to replace _all_ semaphore uses. down_trylock() is used only 54 times in drivers/*, while down() is used 2986 times. And even of those 54 cases, only a small minority does it from an IRQ context.
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