On 03/07/2013 05:42 PM, Chuansheng Liu wrote:
>
> 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....@intel.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));
The idea is good but it could be pushed a bit further.
Instead of changing cpuidle_state_table to an array, change it to an
initdata and the functions intel_idle_cpuidle_driver_init,
intel_idle_probe to init functions.
That would also be nice to get rid of a global variable to store the
current cpu data and let the intel_idle_probe to return the pointer to
the right table.
> if (boot_cpu_has(X86_FEATURE_ARAT)) /* Always Reliable APIC Timer */
> lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
>
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