Messages in this thread | | | Date | Wed, 7 Jun 2023 00:07:13 +0200 | From | Frederic Weisbecker <> | Subject | Re: Loongson (and other $ARCHs?) idle VS timer enqueue |
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On Tue, Apr 25, 2023 at 01:49:37PM +0200, Peter Zijlstra wrote: > Would not something like the below be a more compact form? > That is; afaict there is no reason to keep it 32 bytes, we can easily go > 16 and drop 4 nops. > > Additionally, instead of truncating to the start, increase to the end by > doing: > > ip |= 0xf; > ip++; > > Also; I added a wee comment. > > > diff --git a/arch/loongarch/kernel/genex.S b/arch/loongarch/kernel/genex.S > index 44ff1ff64260..3c8a6bab98fe 100644 > --- a/arch/loongarch/kernel/genex.S > +++ b/arch/loongarch/kernel/genex.S > @@ -18,27 +18,31 @@ > > .align 5 > SYM_FUNC_START(__arch_cpu_idle) > - /* start of rollback region */ > - LONG_L t0, tp, TI_FLAGS > - nop > - andi t0, t0, _TIF_NEED_RESCHED > - bnez t0, 1f > - nop > - nop > - nop > + /* start of idle interrupt region */ > + move t0, CSR_CRMD_IE > + csrxchg t0, t0, LOONGARCH_CSR_CRMD > + /* > + * If an interrupt lands here; between enabling interrupts above and > + * going idle on the next instruction, we must *NOT* go idle since the > + * interrupt could have set TIF_NEED_RESCHED or caused an timer to need > + * reprogramming. Fall through -- see handle_vint() below -- and have > + * the idle loop take care of things. > + */ > idle 0 > - /* end of rollback region */ > -1: jr ra > + nop > + /* end of idle interrupt region */ > +SYM_INNER_LBEL(__arch_cpu_idle_exit, SYM_L_LOCAL) > + jr ra > SYM_FUNC_END(__arch_cpu_idle) > > SYM_FUNC_START(handle_vint) > BACKUP_T0T1 > SAVE_ALL > - la_abs t1, __arch_cpu_idle > + la_abs t1, __arch_cpu_idle_exit > LONG_L t0, sp, PT_ERA > - /* 32 byte rollback region */ > - ori t0, t0, 0x1f > - xori t0, t0, 0x1f > + /* 16 byte idle interrupt region */ > + ori t0, t0, 0x0f > + addi.d t0, t0, 1 > bne t0, t1, 1f > LONG_S t0, sp, PT_ERA > 1: move a0, sp > diff --git a/arch/loongarch/kernel/idle.c b/arch/loongarch/kernel/idle.c > index 0b5dd2faeb90..5ba72d229920 100644 > --- a/arch/loongarch/kernel/idle.c > +++ b/arch/loongarch/kernel/idle.c > @@ -11,7 +11,6 @@ > > void __cpuidle arch_cpu_idle(void) > { > - raw_local_irq_enable(); > __arch_cpu_idle(); /* idle instruction needs irq enabled */ > raw_local_irq_disable(); > }
What is the status of this? Is someone from loongarch going to take it?
Thanks.
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