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authorSuresh Siddha <suresh.b.siddha@intel.com>2009-03-17 10:16:54 -0800
committerIngo Molnar <mingo@elte.hu>2009-03-18 09:36:14 +0100
commitce4e240c279a31096f74afa6584a62d64a1ba8c8 (patch)
tree2b5f7bdf6dc058c09257977929d8f622e6c09466 /arch/x86/kernel/apic/x2apic_phys.c
parentfa4b57cc045d6134b9862b2873f9c8ba9ed53ffe (diff)
x86: add x2apic_wrmsr_fence() to x2apic flush tlb paths
Impact: optimize APIC IPI related barriers Uncached MMIO accesses for xapic are inherently serializing and hence we don't need explicit barriers for xapic IPI paths. x2apic MSR writes/reads don't have serializing semantics and hence need a serializing instruction or mfence, to make all the previous memory stores globally visisble before the x2apic msr write for IPI. Add x2apic_wrmsr_fence() in flush tlb path to x2apic specific paths. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: "steiner@sgi.com" <steiner@sgi.com> Cc: Nick Piggin <npiggin@suse.de> LKML-Reference: <1237313814.27006.203.camel@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/apic/x2apic_phys.c')
-rw-r--r--arch/x86/kernel/apic/x2apic_phys.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index 23625b9f98b..a284359627e 100644
--- a/arch/x86/kernel/apic/x2apic_phys.c
+++ b/arch/x86/kernel/apic/x2apic_phys.c
@@ -58,6 +58,8 @@ static void x2apic_send_IPI_mask(const struct cpumask *mask, int vector)
unsigned long query_cpu;
unsigned long flags;
+ x2apic_wrmsr_fence();
+
local_irq_save(flags);
for_each_cpu(query_cpu, mask) {
__x2apic_send_IPI_dest(per_cpu(x86_cpu_to_apicid, query_cpu),
@@ -73,6 +75,8 @@ static void
unsigned long query_cpu;
unsigned long flags;
+ x2apic_wrmsr_fence();
+
local_irq_save(flags);
for_each_cpu(query_cpu, mask) {
if (query_cpu != this_cpu)
@@ -89,6 +93,8 @@ static void x2apic_send_IPI_allbutself(int vector)
unsigned long query_cpu;
unsigned long flags;
+ x2apic_wrmsr_fence();
+
local_irq_save(flags);
for_each_online_cpu(query_cpu) {
if (query_cpu == this_cpu)