2010-01-18 02:02:11

by Anton Blanchard

Subject: [PATCH] generic-ipi: Use DEFINE_PER_CPU_SHARED_ALIGNED for IPI data

From: Milton Miller <[email protected]>

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

Looking for hot lines, I saw call_function_data shared with tick_cpu_sched.

Signed-off-by: Milton Miller <[email protected]>
Acked-by: Anton Blanchard <[email protected]>
---

Index: linux.trees.git/kernel/smp.c
===================================================================
--- linux.trees.git.orig/kernel/smp.c 2010-01-18 12:41:28.000000000 +1100
+++ linux.trees.git/kernel/smp.c 2010-01-18 12:47:42.000000000 +1100
@@ -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_in
}
}

-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

2010-01-18 07:27:07

by Jens Axboe

Subject: Re: [PATCH] generic-ipi: Use DEFINE_PER_CPU_SHARED_ALIGNED for IPI data

On Mon, Jan 18 2010, Anton Blanchard wrote:
> From: Milton Miller <[email protected]>
>
> The smp ipi data is passed around and given write access by other cpus
> and should be seperated from per-cpu data consumed by this cpu.
>
> Looking for hot lines, I saw call_function_data shared with tick_cpu_sched.

Looks good to me.

Acked-by: Jens Axboe <[email protected]>

--
Jens Axboe

2010-01-19 14:23:59

by Milton Miller

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

Commit-ID: e03bcb68629c7f0728c95f1afe06ce48565c7713
Gitweb: http://git.kernel.org/tip/e03bcb68629c7f0728c95f1afe06ce48565c7713
Author: Milton Miller <[email protected]>
AuthorDate: Mon, 18 Jan 2010 13:00:51 +1100
Committer: Ingo Molnar <[email protected]>
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
tick_cpu_sched.

Signed-off-by: Milton Miller <[email protected]>
Acked-by: Anton Blanchard <[email protected]>
Acked-by: Jens Axboe <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: : Nick Piggin <[email protected]>
LKML-Reference: <20100118020051.GR12666@kryten>
Signed-off-by: Ingo Molnar <[email protected]>
---
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