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authorIngo Molnar <mingo@elte.hu>2009-01-15 22:15:53 +0900
committerIngo Molnar <mingo@elte.hu>2009-01-16 14:20:31 +0100
commit6dbde3530850d4d8bfc1b6bd4006d92786a2787f (patch)
tree08c6dd55e860827311b889e2ecfe3de9f51421a0 /arch/x86/kernel/tlb_32.c
parent004aa322f855a765741d9437a98dd8fe2e4f32a6 (diff)
percpu: add optimized generic percpu accessors
It is an optimization and a cleanup, and adds the following new generic percpu methods: percpu_read() percpu_write() percpu_add() percpu_sub() percpu_and() percpu_or() percpu_xor() and implements support for them on x86. (other architectures will fall back to a default implementation) The advantage is that for example to read a local percpu variable, instead of this sequence: return __get_cpu_var(var); ffffffff8102ca2b: 48 8b 14 fd 80 09 74 mov -0x7e8bf680(,%rdi,8),%rdx ffffffff8102ca32: 81 ffffffff8102ca33: 48 c7 c0 d8 59 00 00 mov $0x59d8,%rax ffffffff8102ca3a: 48 8b 04 10 mov (%rax,%rdx,1),%rax We can get a single instruction by using the optimized variants: return percpu_read(var); ffffffff8102ca3f: 65 48 8b 05 91 8f fd mov %gs:0x7efd8f91(%rip),%rax I also cleaned up the x86-specific APIs and made the x86 code use these new generic percpu primitives. tj: * fixed generic percpu_sub() definition as Roel Kluin pointed out * added percpu_and() for completeness's sake * made generic percpu ops atomic against preemption Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'arch/x86/kernel/tlb_32.c')
-rw-r--r--arch/x86/kernel/tlb_32.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/arch/x86/kernel/tlb_32.c b/arch/x86/kernel/tlb_32.c
index ec53818f4e3..e65449d0f7d 100644
--- a/arch/x86/kernel/tlb_32.c
+++ b/arch/x86/kernel/tlb_32.c
@@ -34,8 +34,8 @@ static DEFINE_SPINLOCK(tlbstate_lock);
*/
void leave_mm(int cpu)
{
- BUG_ON(x86_read_percpu(cpu_tlbstate.state) == TLBSTATE_OK);
- cpu_clear(cpu, x86_read_percpu(cpu_tlbstate.active_mm)->cpu_vm_mask);
+ BUG_ON(percpu_read(cpu_tlbstate.state) == TLBSTATE_OK);
+ cpu_clear(cpu, percpu_read(cpu_tlbstate.active_mm)->cpu_vm_mask);
load_cr3(swapper_pg_dir);
}
EXPORT_SYMBOL_GPL(leave_mm);
@@ -103,8 +103,8 @@ void smp_invalidate_interrupt(struct pt_regs *regs)
* BUG();
*/
- if (flush_mm == x86_read_percpu(cpu_tlbstate.active_mm)) {
- if (x86_read_percpu(cpu_tlbstate.state) == TLBSTATE_OK) {
+ if (flush_mm == percpu_read(cpu_tlbstate.active_mm)) {
+ if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK) {
if (flush_va == TLB_FLUSH_ALL)
local_flush_tlb();
else
@@ -222,7 +222,7 @@ static void do_flush_tlb_all(void *info)
unsigned long cpu = smp_processor_id();
__flush_tlb_all();
- if (x86_read_percpu(cpu_tlbstate.state) == TLBSTATE_LAZY)
+ if (percpu_read(cpu_tlbstate.state) == TLBSTATE_LAZY)
leave_mm(cpu);
}