Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932297Ab3CGJtf (ORCPT ); Thu, 7 Mar 2013 04:49:35 -0500 Received: from mail-pb0-f53.google.com ([209.85.160.53]:39065 "EHLO mail-pb0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755286Ab3CGJta (ORCPT ); Thu, 7 Mar 2013 04:49:30 -0500 Message-ID: <513862A5.7060600@linaro.org> Date: Thu, 07 Mar 2013 10:49:25 +0100 From: Daniel Lezcano User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Chuansheng Liu CC: lenb@kernel.org, len.brown@intel.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] intel_idle: set the state_tables array into __initdata to save mem References: <1362674529.31506.17.camel@cliu38-desktop-build> In-Reply-To: <1362674529.31506.17.camel@cliu38-desktop-build> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4305 Lines: 115 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 > --- > 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; > -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/