On Mon, 2011-12-12 at 17:10 +0800, Tiejun Chen wrote:
> -#else /* !CONFIG_PREEMPT */
> ld r3,_MSR(r1) /* Returning to user mode? */
> andi. r3,r3,MSR_PR
> - beq restore /* if not, just restore regs and return */
> + bne test_work_user
>
> + clrrdi r9,r1,THREAD_SHIFT /* current_thread_info() */
> + li r0,_TIF_USER_WORK_MASK
You meant _TIF_KERNEL_WORK_MASK ?
> +#ifdef CONFIG_PREEMPT
> + ori r0,r0,_TIF_NEED_RESCHED
> +#endif
No, include that in _TIF_KERNEL_WORK_MASK when CONFIG_PREEMPT, ie,
modify the definition of _TIF_KERNEL_WORK_MASK to include it
> + ld r4,TI_FLAGS(r9)
> + and. r0,r4,r0 /* check NEED_RESCHED and maybe
> _TIF_USER_WORK_MASK */
Comment is wrong after the above
> + bne do_kernel_work
> + b restore /* if so, just restore regs and return */
> +
> +test_work_user:
> /* Check current_thread_info()->flags */
> clrrdi r9,r1,THREAD_SHIFT
> ld r4,TI_FLAGS(r9)
For better scheduling, couldn't you have preloaded the TIF flags, then
checked for PR ?
Looks like this (also replaces do_work)
IE. ld r3,_MSR(r1)
clrrdi r9,r1,THREAD_SHIFT
ld r4,TI_FLAGS(r9)
andi. r3,r3,MSR_PR
bne test_work_user
test_work_kernel:
andi. r0,r4,_TIF_KERNEL_WORK_MASK
beq+ restore
#ifdef CONFIG_PREEMPT
/* Check if we need to preempt */
andi. r0,r4,_TIF_NEED_RESCHED
beq+ 2f
lwz r8,TI_PREEMPT(r9)
cmpwi cr1,r8,0
ld r0,SOFTE(r1)
cmpdi r0,0
crandc eq,cr1*4+eq,eq
bne 1f
/* ... copy comment about preempt here ... */
li r0,0
stb r0,PACASOFTIRQEN(r13)
stb r0,PACAHARDIRQEN(r13)
TRACE_DISABLE_INTS
1: bl .preempt_schedule_irq
/* preempt may have re-enabled and then disabled interrupts,
* so we may come here as soft-disabled & hard-enabled, but
* we really want hard disabled.
*/
#ifdef CONFIG_PPC_BOOK3E
wrteei 0
#else
mfmsr r10
rldicl r10,r10,48,1
rotldi r10,r10,16
mtmsrd r10,1
#endif
li r0,0
stb r0,PACAHARDIRQEN(r13)
/* Re-check if we need to preempt again */
clrrdi r9,r1,THREAD_SHIFT
ld r4,TI_FLAGS(r9)
andi. r0,r4,_TIF_NEED_RESCHED
bne 1b
2:
#endif /* CONFIG_PREEMPT */
andi. r0,r4,_TIF_OUR_NEW_FLAG
beq+ restore
... handle our new flag here
b restore
test_work_user:
andi. r0,r4,_TIF_USER_WORK_MASK
beq+ restore
/* ... move user_work here ... */
> andi. r0,r4,_TIF_USER_WORK_MASK
> - bne do_work
> -#endif
> + bne do_user_work
>
> restore:
> BEGIN_FW_FTR_SECTION
> @@ -693,10 +692,8 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
> b .ret_from_except_lite /* loop back and handle more */
> #endif
>
> -do_work:
> +do_kernel_work:
> #ifdef CONFIG_PREEMPT
> - andi. r0,r3,MSR_PR /* Returning to user mode? */
> - bne user_work
> /* Check that preempt_count() == 0 and interrupts are enabled */
> lwz r8,TI_PREEMPT(r9)
> cmpwi cr1,r8,0
> @@ -738,9 +735,9 @@ do_work:
> bne 1b
> b restore
>
> -user_work:
> #endif /* CONFIG_PREEMPT */
>
> +do_user_work:
> /* Enable interrupts */
> #ifdef CONFIG_PPC_BOOK3E
> wrteei 1
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