linux-kernel - [PATCH] intel_idle: set the state_tables array into _

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Date:	Fri, 08 Mar 2013 00:42:09 +0800
From:	Chuansheng Liu <chuansheng.liu@...el.com>
To:	lenb@...nel.org, len.brown@...el.com
Cc:	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	chuansheng.liu@...el.com
Subject: [PATCH] intel_idle: set the state_tables array into __initdata to
 save mem


Currently, in intel_idle.c, there are 5 state_tables array, every
array size is sizeof(struct cpuidle_state) * CPUIDLE_STATE_MAX.

But after intel_idle_probe(), just only one array is useful.

Here we can just define one static state_table, and initialize it
in intel_idle_probe(), and set other data state_tables as __initdata.

It can save about 3K, which also benefits mobile devices.

Signed-off-by: liu chuansheng <chuansheng.liu@...el.com>
---
 drivers/idle/intel_idle.c |   19 ++++++++++++-------
 1 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 5d66750..0642bfe 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -99,7 +99,7 @@ static int intel_idle(struct cpuidle_device *dev,
 			struct cpuidle_driver *drv, int index);
 static int intel_idle_cpu_init(int cpu);
 
-static struct cpuidle_state *cpuidle_state_table;
+static struct cpuidle_state cpuidle_state_table[CPUIDLE_STATE_MAX];
 
 /*
  * Set this flag for states where the HW flushes the TLB for us
@@ -124,7 +124,7 @@ static struct cpuidle_state *cpuidle_state_table;
  * which is also the index into the MWAIT hint array.
  * Thus C0 is a dummy.
  */
-static struct cpuidle_state nehalem_cstates[CPUIDLE_STATE_MAX] = {
+static struct cpuidle_state nehalem_cstates[CPUIDLE_STATE_MAX] __initdata = {
 	{
 		.name = "C1-NHM",
 		.desc = "MWAIT 0x00",
@@ -157,7 +157,7 @@ static struct cpuidle_state nehalem_cstates[CPUIDLE_STATE_MAX] = {
 		.enter = NULL }
 };
 
-static struct cpuidle_state snb_cstates[CPUIDLE_STATE_MAX] = {
+static struct cpuidle_state snb_cstates[CPUIDLE_STATE_MAX] __initdata = {
 	{
 		.name = "C1-SNB",
 		.desc = "MWAIT 0x00",
@@ -197,7 +197,7 @@ static struct cpuidle_state snb_cstates[CPUIDLE_STATE_MAX] = {
 		.enter = NULL }
 };
 
-static struct cpuidle_state ivb_cstates[CPUIDLE_STATE_MAX] = {
+static struct cpuidle_state ivb_cstates[CPUIDLE_STATE_MAX] __initdata = {
 	{
 		.name = "C1-IVB",
 		.desc = "MWAIT 0x00",
@@ -237,7 +237,7 @@ static struct cpuidle_state ivb_cstates[CPUIDLE_STATE_MAX] = {
 		.enter = NULL }
 };
 
-static struct cpuidle_state hsw_cstates[CPUIDLE_STATE_MAX] = {
+static struct cpuidle_state hsw_cstates[CPUIDLE_STATE_MAX] __initdata = {
 	{
 		.name = "C1-HSW",
 		.desc = "MWAIT 0x00",
@@ -277,7 +277,7 @@ static struct cpuidle_state hsw_cstates[CPUIDLE_STATE_MAX] = {
 		.enter = NULL }
 };
 
-static struct cpuidle_state atom_cstates[CPUIDLE_STATE_MAX] = {
+static struct cpuidle_state atom_cstates[CPUIDLE_STATE_MAX] __initdata = {
 	{
 		.name = "C1E-ATM",
 		.desc = "MWAIT 0x00",
@@ -504,7 +504,12 @@ static int intel_idle_probe(void)
 	pr_debug(PREFIX "MWAIT substates: 0x%x\n", mwait_substates);
 
 	icpu = (const struct idle_cpu *)id->driver_data;
-	cpuidle_state_table = icpu->state_table;
+	/* Copy the icpu->state_table into cpuidle_state_table,
+	 * The pointing array by icpu->state_table is with __initdata,
+	 * which will be freed after kernel init ending.
+	 */
+	memcpy(cpuidle_state_table, icpu->state_table,
+			sizeof(cpuidle_state_table));
 
 	if (boot_cpu_has(X86_FEATURE_ARAT))	/* Always Reliable APIC Timer */
 		lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
-- 
1.7.0.4



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