Commit-ID: 287de5b2cb365b98190b5de8ace1c5a31768a5ae
Gitweb: http://git.kernel.org/tip/287de5b2cb365b98190b5de8ace1c5a31768a5ae
Author: Shaohua Li <shaohua.li@xxxxxxxxx>
AuthorDate: Tue, 15 Nov 2011 14:49:02 -0800
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Mon, 5 Dec 2011 17:11:50 +0100
x86/mm: Avoid superflous leave_mm() in the TLB flush path
If just one page VA tlb is required to be flushed and current
task is in lazy TLB state, doing leave_mm() is superfluous
because it flushes the whole TLB. This can reduce some TLB
miss.
Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/mm/tlb.c | 16 ++++++----------
1 files changed, 6 insertions(+), 10 deletions(-)
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index d6c0418..3041665 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -153,13 +153,13 @@ void smp_invalidate_interrupt(struct pt_regs *regs)
*/
if (f->flush_mm == percpu_read(cpu_tlbstate.active_mm)) {
- if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK) {
- if (f->flush_va == TLB_FLUSH_ALL)
+ if (f->flush_va == TLB_FLUSH_ALL) {
+ if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK)
local_flush_tlb();
else
- __flush_tlb_one(f->flush_va);
+ leave_mm(cpu);
} else
- leave_mm(cpu);
+ __flush_tlb_one(f->flush_va);
}
out:
ack_APIC_irq();
@@ -306,12 +306,8 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long va)
preempt_disable();
- if (current->active_mm == mm) {
- if (current->mm)
- __flush_tlb_one(va);
- else
- leave_mm(smp_processor_id());
- }
+ if (current->active_mm == mm)
+ __flush_tlb_one(va);
if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids)
flush_tlb_others(mm_cpumask(mm), mm, va);
--
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