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

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

[Oleg Nesterov]

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 <oleg@tv-sign.ru>

--- 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);
 }
 
 /*

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

[Ingo Molnar]

* Oleg Nesterov <oleg@tv-sign.ru> 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 <oleg@tv-sign.ru>

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 <mingo@elte.hu>

	Ingo

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

[David Howells]

Oleg Nesterov <oleg@tv-sign.ru> 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 <dhowells@redhat.com>