[tip:core/ipi] generic-ipi: Optimize accesses by using DEFINE_PER_CPU_SHARED_ALIGNED for IPI data

From: tip-bot for Milton Miller
Date: Tue Jan 19 2010 - 09:24:05 EST

Commit-ID: e03bcb68629c7f0728c95f1afe06ce48565c7713
Gitweb: http://git.kernel.org/tip/e03bcb68629c7f0728c95f1afe06ce48565c7713
Author: Milton Miller <miltonm@xxxxxxx>
AuthorDate: Mon, 18 Jan 2010 13:00:51 +1100
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Mon, 18 Jan 2010 09:02:59 +0100

generic-ipi: Optimize accesses by using DEFINE_PER_CPU_SHARED_ALIGNED for IPI data

The smp ipi data is passed around and given write access by
other cpus and should be separated from per-cpu data consumed by
this cpu.

Looking for hot lines, I saw call_function_data shared with

Signed-off-by: Milton Miller <miltonm@xxxxxxx>
Acked-by: Anton Blanchard <anton@xxxxxxxxx>
Acked-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: : Nick Piggin <npiggin@xxxxxxx>
LKML-Reference: <20100118020051.GR12666@kryten>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
kernel/smp.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/smp.c b/kernel/smp.c
index f104084..9867b6b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -12,8 +12,6 @@
#include <linux/smp.h>
#include <linux/cpu.h>

-static DEFINE_PER_CPU(struct call_single_queue, call_single_queue);
static struct {
struct list_head queue;
raw_spinlock_t lock;
@@ -33,12 +31,14 @@ struct call_function_data {
cpumask_var_t cpumask;

+static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data);
struct call_single_queue {
struct list_head list;
raw_spinlock_t lock;

-static DEFINE_PER_CPU(struct call_function_data, cfd_data);
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_queue, call_single_queue);

static int
hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
@@ -256,7 +256,7 @@ void generic_smp_call_function_single_interrupt(void)

-static DEFINE_PER_CPU(struct call_single_data, csd_data);
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);

* smp_call_function_single - Run a function on a specific CPU
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