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x86, 32-bit: improve lazy TLB handling code

Browse source 
Impact: micro-optimize the 32-bit TLB flush code

Use the faster x86_{read,write}_percpu() accessors here.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jan Beulich 2008-12-16 11:46:58 +00:00 committed by Ingo Molnar
parent 1796316a8b
commit cfc319833b
2 changed files with 11 additions and 13 deletions
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13
arch/x86/include/asm/mmu_context_32.h
View file

@ -4,9 +4,8 @@
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
#ifdef CONFIG_SMP
unsigned cpu = smp_processor_id();
if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_LAZY;
if (x86_read_percpu(cpu_tlbstate.state) == TLBSTATE_OK)
x86_write_percpu(cpu_tlbstate.state, TLBSTATE_LAZY);
#endif
}
@ -20,8 +19,8 @@ static inline void switch_mm(struct mm_struct *prev,
/* stop flush ipis for the previous mm */
cpu_clear(cpu, prev->cpu_vm_mask);
#ifdef CONFIG_SMP
per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_OK;
per_cpu(cpu_tlbstate, cpu).active_mm = next;
x86_write_percpu(cpu_tlbstate.state, TLBSTATE_OK);
x86_write_percpu(cpu_tlbstate.active_mm, next);
#endif
cpu_set(cpu, next->cpu_vm_mask);
@ -36,8 +35,8 @@ static inline void switch_mm(struct mm_struct *prev,
}
#ifdef CONFIG_SMP
else {
per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_OK;
BUG_ON(per_cpu(cpu_tlbstate, cpu).active_mm != next);
x86_write_percpu(cpu_tlbstate.state, TLBSTATE_OK);
BUG_ON(x86_read_percpu(cpu_tlbstate.active_mm) != next);
if (!cpu_test_and_set(cpu, next->cpu_vm_mask)) {
/* We were in lazy tlb mode and leave_mm disabled

11
arch/x86/kernel/tlb_32.c
View file

@ -34,9 +34,8 @@ static DEFINE_SPINLOCK(tlbstate_lock);
*/
void leave_mm(int cpu)
{
if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
BUG();
cpu_clear(cpu, per_cpu(cpu_tlbstate, cpu).active_mm->cpu_vm_mask);
BUG_ON(x86_read_percpu(cpu_tlbstate.state) == TLBSTATE_OK);
cpu_clear(cpu, x86_read_percpu(cpu_tlbstate.active_mm)->cpu_vm_mask);
load_cr3(swapper_pg_dir);
}
EXPORT_SYMBOL_GPL(leave_mm);
@ -104,8 +103,8 @@ void smp_invalidate_interrupt(struct pt_regs *regs)
* BUG();
*/
if (flush_mm == per_cpu(cpu_tlbstate, cpu).active_mm) {
if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK) {
if (flush_mm == x86_read_percpu(cpu_tlbstate.active_mm)) {
if (x86_read_percpu(cpu_tlbstate.state) == TLBSTATE_OK) {
if (flush_va == TLB_FLUSH_ALL)
local_flush_tlb();
else
@ -238,7 +237,7 @@ static void do_flush_tlb_all(void *info)
unsigned long cpu = smp_processor_id();
__flush_tlb_all();
if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_LAZY)
if (x86_read_percpu(cpu_tlbstate.state) == TLBSTATE_LAZY)
leave_mm(cpu);
}