[PATCH] x86-64: Make remote TLB flush more scalable

Instead of using a global spinlock to protect the state
of the remote TLB flush use a lock and state for each sending CPU.

To tell the receiver where to look for the state use 8 different
call vectors.  Each CPU uses a specific vector to trigger flushes on other
CPUs. Depending on the received vector the target CPUs look into
the right per cpu variable for the flush data.

When the system has more than 8 CPUs they are hashed to the 8 available
vectors. The limited global vector space forces us to this right now.
In future when interrupts are split into per CPU domains this could be
fixed, at the cost of needing more IPIs in flat mode.

Also some minor cleanup in the smp flush code and remove some outdated
debug code.

Requires patch to move cpu_possible_map setup earlier.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/arch/x86_64/kernel/entry.S b/arch/x86_64/kernel/entry.S
index 3620508c8bd9..873c39d8f818 100644
--- a/arch/x86_64/kernel/entry.S
+++ b/arch/x86_64/kernel/entry.S
@@ -536,8 +536,19 @@ ENTRY(thermal_interrupt)
 ENTRY(reschedule_interrupt)
         apicinterrupt RESCHEDULE_VECTOR,smp_reschedule_interrupt
 
-ENTRY(invalidate_interrupt)
-        apicinterrupt INVALIDATE_TLB_VECTOR,smp_invalidate_interrupt
+        .macro INVALIDATE_ENTRY num
+ENTRY(invalidate_interrupt\num)
+        apicinterrupt INVALIDATE_TLB_VECTOR_START+\num,smp_invalidate_interrupt 
+        .endm
+
+        INVALIDATE_ENTRY 0
+        INVALIDATE_ENTRY 1
+        INVALIDATE_ENTRY 2
+        INVALIDATE_ENTRY 3
+        INVALIDATE_ENTRY 4
+        INVALIDATE_ENTRY 5
+        INVALIDATE_ENTRY 6
+        INVALIDATE_ENTRY 7
 
 ENTRY(call_function_interrupt)
         apicinterrupt CALL_FUNCTION_VECTOR,smp_call_function_interrupt