Messages in this thread | | | Date | Fri, 12 Dec 2003 03:37:23 +1100 | From | Nick Piggin <> | Subject | Re: [CFT][RFC] HT scheduler |
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William Lee Irwin III wrote:
>William Lee Irwin III wrote: > >>>There is a spinloop in __up_read(), which is probably it. >>> > >On Fri, Dec 12, 2003 at 02:51:32AM +1100, Nick Piggin wrote: > >>Oh I see - in rwsem_wake? >> > >Even before that: > >static inline void __up_read(struct rw_semaphore *sem) >{ > __s32 tmp = -RWSEM_ACTIVE_READ_BIAS; > __asm__ __volatile__( > "# beginning __up_read\n\t" >LOCK_PREFIX " xadd %%edx,(%%eax)\n\t" /* subtracts 1, returns the old value */ > " js 2f\n\t" /* jump if the lock is being waited upon */ > "1:\n\t" > LOCK_SECTION_START("") > "2:\n\t" > " decw %%dx\n\t" /* do nothing if still outstanding active readers > */ > " jnz 1b\n\t" > " pushl %%ecx\n\t" > " call rwsem_wake\n\t" > " popl %%ecx\n\t" > " jmp 1b\n" > LOCK_SECTION_END >
I think there shouldn't be a loop - remember the lock section.
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