2006-12-03 18:16:51

by Oleg Nesterov

Subject: [PATCH] i386/kernel/smp.c: don't use set_irq_regs()

We don't need to setup _irq_regs in smp_xxx_interrupt (except apic timer).
These handlers run with irqs disabled and do not call functions which need
"struct pt_regs".

Signed-off-by: Oleg Nesterov <[email protected]>

--- 19-rc6/arch/i386/kernel/smp.c~regs 2006-11-17 19:42:22.000000000 +0300
+++ 19-rc6/arch/i386/kernel/smp.c 2006-12-03 20:51:41.000000000 +0300
@@ -321,7 +321,6 @@ static inline void leave_mm (unsigned lo

fastcall void smp_invalidate_interrupt(struct pt_regs *regs)
{
- struct pt_regs *old_regs = set_irq_regs(regs);
unsigned long cpu;

cpu = get_cpu();
@@ -352,7 +351,6 @@ fastcall void smp_invalidate_interrupt(s
smp_mb__after_clear_bit();
out:
put_cpu_no_resched();
- set_irq_regs(old_regs);
}

static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
@@ -607,14 +605,11 @@ void smp_send_stop(void)
*/
fastcall void smp_reschedule_interrupt(struct pt_regs *regs)
{
- struct pt_regs *old_regs = set_irq_regs(regs);
ack_APIC_irq();
- set_irq_regs(old_regs);
}

fastcall void smp_call_function_interrupt(struct pt_regs *regs)
{
- struct pt_regs *old_regs = set_irq_regs(regs);
void (*func) (void *info) = call_data->func;
void *info = call_data->info;
int wait = call_data->wait;
@@ -637,7 +632,6 @@ fastcall void smp_call_function_interrup
mb();
atomic_inc(&call_data->finished);
}
- set_irq_regs(old_regs);
}

/*

2006-12-04 09:49:09

by Ingo Molnar

Subject: Re: [PATCH] i386/kernel/smp.c: don't use set_irq_regs()

* Oleg Nesterov <[email protected]> wrote:

> We don't need to setup _irq_regs in smp_xxx_interrupt (except apic
> timer). These handlers run with irqs disabled and do not call
> functions which need "struct pt_regs".
>
> Signed-off-by: Oleg Nesterov <[email protected]>

yeah. These are leftover inefficiencies from the ptregs conversion,
which just added a regs variable to every arch-level irq handler
blindly.

Acked-by: Ingo Molnar <[email protected]>

Ingo

2006-12-04 11:25:31

by David Howells

Subject: Re: [PATCH] i386/kernel/smp.c: don't use set_irq_regs()

Oleg Nesterov <[email protected]> wrote:

> We don't need to setup _irq_regs in smp_xxx_interrupt (except apic timer).
> These handlers run with irqs disabled and do not call functions which need
> "struct pt_regs".

Acked-By: David Howells <[email protected]>