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authorSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>2014-02-26 05:37:43 +0530
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2014-03-05 15:55:04 +1100
commit1b67bee129a36c22c17186cc2a9981678e9323ee (patch)
treeaf3787d56f78a8f4624aabb7771589deb1428192 /arch/powerpc/platforms
parent402d9a1e02f7215628f13b7c80ff3e98c3a0cadc (diff)
downloadlinux-1b67bee129a36c22c17186cc2a9981678e9323ee.tar.bz2
powerpc: Implement tick broadcast IPI as a fixed IPI message
For scalability and performance reasons, we want the tick broadcast IPIs to be handled as efficiently as possible. Fixed IPI messages are one of the most efficient mechanisms available - they are faster than the smp_call_function mechanism because the IPI handlers are fixed and hence they don't involve costly operations such as adding IPI handlers to the target CPU's function queue, acquiring locks for synchronization etc. Luckily we have an unused IPI message slot, so use that to implement tick broadcast IPIs efficiently. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> [Functions renamed to tick_broadcast* and Changelog modified by Preeti U. Murthy<preeti@linux.vnet.ibm.com>] Signed-off-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com> Acked-by: Geoff Levand <geoff@infradead.org> [For the PS3 part] Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/platforms')
-rw-r--r--arch/powerpc/platforms/cell/interrupt.c2
-rw-r--r--arch/powerpc/platforms/ps3/smp.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/platforms/cell/interrupt.c b/arch/powerpc/platforms/cell/interrupt.c
index adf372606a1c..8a106b4172e0 100644
--- a/arch/powerpc/platforms/cell/interrupt.c
+++ b/arch/powerpc/platforms/cell/interrupt.c
@@ -215,7 +215,7 @@ void iic_request_IPIs(void)
{
iic_request_ipi(PPC_MSG_CALL_FUNCTION);
iic_request_ipi(PPC_MSG_RESCHEDULE);
- iic_request_ipi(PPC_MSG_UNUSED);
+ iic_request_ipi(PPC_MSG_TICK_BROADCAST);
iic_request_ipi(PPC_MSG_DEBUGGER_BREAK);
}
diff --git a/arch/powerpc/platforms/ps3/smp.c b/arch/powerpc/platforms/ps3/smp.c
index 00d1a7c2a5a4..b358bec6c8cb 100644
--- a/arch/powerpc/platforms/ps3/smp.c
+++ b/arch/powerpc/platforms/ps3/smp.c
@@ -76,7 +76,7 @@ static int __init ps3_smp_probe(void)
BUILD_BUG_ON(PPC_MSG_CALL_FUNCTION != 0);
BUILD_BUG_ON(PPC_MSG_RESCHEDULE != 1);
- BUILD_BUG_ON(PPC_MSG_UNUSED != 2);
+ BUILD_BUG_ON(PPC_MSG_TICK_BROADCAST != 2);
BUILD_BUG_ON(PPC_MSG_DEBUGGER_BREAK != 3);
for (i = 0; i < MSG_COUNT; i++) {