aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorAnton Blanchard <anton@samba.org>2010-01-31 20:32:51 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2010-02-17 14:02:48 +1100
commitfda9d86100e0b412d0c8a16abe0651c8c8e39e81 (patch)
treedccc2fce96c47f35e8f18c282a842fa8113a2e2d
parent8c007bfdf1bab536f824d91fccc76596c18aba78 (diff)
powerpc: Reduce footprint of xics_ipi_struct
Right now we allocate a cacheline sized NR_CPUS array for xics IPI communication. Use DECLARE_PER_CPU_SHARED_ALIGNED to put it in percpu data in its own cacheline since it is written to by other cpus. On a kernel with NR_CPUS=1024, this saves quite a lot of memory: text data bss dec hex filename 8767779 2944260 1505724 13217763 c9afe3 vmlinux.irq_cpustat 8767555 2813444 1505724 13086723 c7b003 vmlinux.xics A saving of around 128kB. Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/platforms/pseries/xics.c26
1 files changed, 11 insertions, 15 deletions
diff --git a/arch/powerpc/platforms/pseries/xics.c b/arch/powerpc/platforms/pseries/xics.c
index 63eaa8a220c..41374e830eb 100644
--- a/arch/powerpc/platforms/pseries/xics.c
+++ b/arch/powerpc/platforms/pseries/xics.c
@@ -510,15 +510,13 @@ static void __init xics_init_host(void)
/*
* XICS only has a single IPI, so encode the messages per CPU
*/
-struct xics_ipi_struct {
- unsigned long value;
- } ____cacheline_aligned;
-
-static struct xics_ipi_struct xics_ipi_message[NR_CPUS] __cacheline_aligned;
+static DEFINE_PER_CPU_SHARED_ALIGNED(unsigned long, xics_ipi_message);
static inline void smp_xics_do_message(int cpu, int msg)
{
- set_bit(msg, &xics_ipi_message[cpu].value);
+ unsigned long *tgt = &per_cpu(xics_ipi_message, cpu);
+
+ set_bit(msg, tgt);
mb();
if (firmware_has_feature(FW_FEATURE_LPAR))
lpar_qirr_info(cpu, IPI_PRIORITY);
@@ -544,25 +542,23 @@ void smp_xics_message_pass(int target, int msg)
static irqreturn_t xics_ipi_dispatch(int cpu)
{
+ unsigned long *tgt = &per_cpu(xics_ipi_message, cpu);
+
WARN_ON(cpu_is_offline(cpu));
mb(); /* order mmio clearing qirr */
- while (xics_ipi_message[cpu].value) {
- if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION,
- &xics_ipi_message[cpu].value)) {
+ while (*tgt) {
+ if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION, tgt)) {
smp_message_recv(PPC_MSG_CALL_FUNCTION);
}
- if (test_and_clear_bit(PPC_MSG_RESCHEDULE,
- &xics_ipi_message[cpu].value)) {
+ if (test_and_clear_bit(PPC_MSG_RESCHEDULE, tgt)) {
smp_message_recv(PPC_MSG_RESCHEDULE);
}
- if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE,
- &xics_ipi_message[cpu].value)) {
+ if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE, tgt)) {
smp_message_recv(PPC_MSG_CALL_FUNC_SINGLE);
}
#if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC)
- if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK,
- &xics_ipi_message[cpu].value)) {
+ if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK, tgt)) {
smp_message_recv(PPC_MSG_DEBUGGER_BREAK);
}
#endif