arm/twd: avoid waking deeply sleeping CPUs for rate change notifier
PATCH 1/1 arm/twd: avoid waking deeply sleeping CPUs for rate change notifier
The current clock notifier sends an IPI to all CPUs, even if they are in deep sleep state with the local timer disabled and switched to tick broadcast. This needlessly cuts the CPU sleep times, as nothing is gained from updating a disabled TWDs rate.
Keep track of the enabled TWDs and only send an IPI to those CPUs with an active local timer. As disabled TWDs may now miss a CPU frequency update we need to make sure to refresh the rate on re-enabling of the timer.
--- arch/arm/kernel/smp_twd.c | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-)
arch/arm/kernel/smp_twd.c +29 -2
@@ -32,6 +32,8 @@ static struct clk *twd_clk;static unsigned long twd_timer_rate; static DEFINE_PER_CPU(bool, percpu_setup_called); +static cpumask_var_t active_twd_mask; +static struct clock_event_device __percpu *twd_evt;static unsigned int twd_features =CLOCK_EVT_FEAT_PERIODIC |CLOCK_EVT_FEAT_ONESHOT ;
@@ -39,12 +41,24 @@ static int twd_ppi;static int twd_shutdown (struct clock_event_device *clk) { +cpumask_clear_cpu (smp_processor_id (), active_twd_mask); +writel_relaxed (0 , twd_base +TWD_TIMER_CONTROL );return 0 ; }static int twd_set_oneshot (struct clock_event_device *clk) { +cpumask_set_cpu (smp_processor_id (), active_twd_mask); + +/* +* When going from shutdown to oneshot we might have missed some +* frequency updates if the CPU was sleeping. Make sure to update +* the timer frequency with the current rate. +*/ +if (clockevent_state_shutdown (clk)) +clockevents_update_freq (clk, twd_timer_rate); +/* period set, and timer enabled in 'next_event' hook */ writel_relaxed (TWD_TIMER_CONTROL_IT_ENABLE |TWD_TIMER_CONTROL_ONESHOT , twd_base +TWD_TIMER_CONTROL );
@@ -57,6 +71,16 @@ static int twd_set_periodic(struct clock_event_device *clk)TWD_TIMER_CONTROL_IT_ENABLE |TWD_TIMER_CONTROL_PERIODIC ; +cpumask_set_cpu (smp_processor_id (), active_twd_mask); + +/* +* When going from shutdown to periodic we might have missed some +* frequency updates if the CPU was sleeping. Make sure to update +* the timer frequency with the current rate. +*/ +if (clockevent_state_shutdown (clk)) +clockevents_update_freq (clk, twd_timer_rate); +writel_relaxed (DIV_ROUND_CLOSEST (twd_timer_rate,HZ ), twd_base +TWD_TIMER_LOAD );writel_relaxed (ctrl, twd_base +TWD_TIMER_CONTROL );
@@ -124,8 +148,8 @@ static int twd_rate_change(struct notifier_block *nb,* changing cpu. */ if (flags ==POST_RATE_CHANGE ) -on_each_cpu (twd_update_frequency, - (void *)&cnd->new_rate,1 ); +on_each_cpu_mask (active_twd_mask, twd_update_frequency, + (void *)&cnd->new_rate,1 );return NOTIFY_OK ; }
@@ -326,6 +350,9 @@ static int __init twd_local_timer_common_register(struct device_node *np) {int err; +if (!zalloc_cpumask_var (&active_twd_mask,GFP_KERNEL )) +return -ENOMEM ; + twd_evt = alloc_percpu(struct clock_event_device);if (!twd_evt) { err = -ENOMEM ;
Signature · 1 line
2.16.3
PATCH 1/1 arm/twd: avoid waking deeply sleeping CPUs for rate change notifier
Hi all,
Am Dienstag, den 17.04.2018, 12:46 +0200 schrieb Lucas Stach:
Quoted 10 lines
The current clock notifier sends an IPI to all CPUs, even if they are in deep sleep state with the local timer disabled and switched to tick broadcast. This needlessly cuts the CPU sleep times, as nothing is gained from updating a disabled TWDs rate.
Keep track of the enabled TWDs and only send an IPI to those CPUs with an active local timer. As disabled TWDs may now miss a CPU frequency update we need to make sure to refresh the rate on re-enabling of the timer.
Signed-off-by Lucas Stach <[email protected]>
I would appreciate some feedback to this patch.
FWIW, I've been running some systems with this patch applied for quite some time now with no issues spotted so far.
Regards,
Lucas
Quoted 80 lines
---
?arch/arm/kernel/smp_twd.c | 31 +++++++++++++++++++++++++++++-- ?1 file changed, 29 insertions(+), 2 deletions(-)arch/arm/kernel/smp_twd.c +0
-0@@ -32,6 +32,8 @@ static struct clk *twd_clk; ?static unsigned long twd_timer_rate; ?static DEFINE_PER_CPU(bool, percpu_setup_called);?
arch/arm/kernel/smp_twd.c +2
-0+static cpumask_var_t active_twd_mask; +?static struct
clock_event_device__percpu*twd_evt; ?static unsigned inttwd_features=Quoted 1 line
?
CLOCK_EVT_FEAT_PERIODIC|CLOCK_EVT_FEAT_ONESHOT;arch/arm/kernel/smp_twd.c +0
-0@@ -39,12 +41,24 @@ static int twd_ppi;?
?static inttwd_shutdown(struct clock_event_device *clk)?{arch/arm/kernel/smp_twd.c static int twd_ppi; · line 44
Quoted 1 line
arch/arm/kernel/smp_twd.c +1
-0+cpumask_clear_cpu (smp_processor_id (), active_twd_mask);+
Quoted 2 lines
?
writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
? return 0;?}
?
?static inttwd_set_oneshot(struct clock_event_device *clk)?{Review
Quoted 1 line
(quoted diff) +1
-0+ cpumask_set_cpu(smp_processor_id(), active_twd_mask);+
Review
Quoted 7 lines
(quoted diff) +7
-0+ /* + ?* When going from shutdown to oneshot we might have missed some + ?* frequency updates if the CPU was sleeping. Make sure to update + ?* the timer frequency with the current rate. + ?*/ + if (clockevent_state_shutdown(clk)) + clockevents_update_freq(clk, twd_timer_rate);+
Quoted 3 lines
? /* period set, and timer enabled in '
next_event' hook */
? writel_relaxed(TWD_TIMER_CONTROL_IT_ENABLE |TWD_TIMER_CONTROL_ONESHOT,
? ???????twd_base +TWD_TIMER_CONTROL);arch/arm/kernel/smp_twd.c +0
-0@@ -57,6 +71,16 @@ static int twd_set_periodic(struct clock_event_device *clk)Quoted 2 lines
? ?????TWD_TIMER_CONTROL_IT_ENABLE |
? ?????TWD_TIMER_CONTROL_PERIODIC;?
Review
Quoted 1 line
(quoted diff) +1
-0+ cpumask_set_cpu(smp_processor_id(), active_twd_mask);+
Review
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(quoted diff) +7
-0+ /* + ?* When going from shutdown to periodic we might have missed some + ?* frequency updates if the CPU was sleeping. Make sure to update + ?* the timer frequency with the current rate. + ?*/ + if (clockevent_state_shutdown(clk)) + clockevents_update_freq(clk, twd_timer_rate);+
Quoted 3 lines
? writel_relaxed(DIV_ROUND_CLOSEST(twd_timer_rate, HZ),
? ???????twd_base +TWD_TIMER_LOAD);
?writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL);arch/arm/kernel/smp_twd.c +0
-0@@ -124,8 +148,8 @@ static int twd_rate_change(struct notifier_block *nb,arch/arm/kernel/smp_twd.c static int twd_rate_change(struct notifier_block *nb,
Quoted 7 lines
? ?* changing cpu.
? ?*/
? if (flags ==POST_RATE_CHANGE)arch/arm/kernel/smp_twd.c +2
-2- on_each_cpu(twd_update_frequency, - ??(void *)&cnd->new_rate, 1); + on_each_cpu_mask(active_twd_mask, twd_update_frequency, + ?(void *)&cnd->new_rate, 1);?
Quoted 1 line
? return
NOTIFY_OK;?}
arch/arm/kernel/smp_twd.c +0
-0@@ -326,6 +350,9 @@ static int __init twd_local_timer_common_register(struct device_node *np) ?{ > ? int err;?
arch/arm/kernel/smp_twd.c static int __init twd_local_timer_common_register(struct device_node *np) · line 354
Quoted 2 lines
arch/arm/kernel/smp_twd.c +2
-0+if (!zalloc_cpumask_var (&active_twd_mask,GFP_KERNEL )) +return -ENOMEM ;+
Quoted 3 lines
?
twd_evt=alloc_percpu(struct clock_event_device);
? if (!twd_evt) {
? err =-ENOMEM;
PATCH 1/1 arm/twd: avoid waking deeply sleeping CPUs for rate change notifier
Hi again,
Am Montag, den 11.06.2018, 18:16 +0200 schrieb Lucas Stach:
Quoted 12 lines
Hi all,
Am Dienstag, den 17.04.2018, 12:46 +0200 schrieb Lucas Stach:
Quoted 9 lines
The current clock notifier sends an IPI to all CPUs, even if they are in deep sleep state with the local timer disabled and switched to tick broadcast. This needlessly cuts the CPU sleep times, as nothing is gained from updating a disabled TWDs rate.
Keep track of the enabled TWDs and only send an IPI to those CPUs with an active local timer. As disabled TWDs may now miss a CPU frequency update we need to make sure to refresh the rate on re-enabling of the timer.
Quoted 5 lines
Quoted 1 line
Signed-off-by Lucas Stach <[email protected]>I would appreciate some feedback to this patch.
FWIW, I've been running some systems with this patch applied for quite some time now with no issues spotted so far.
Can I persuade anyone to take a look at this?
It's been some months since I've posted this and haven't got any feedback so far. I'm running this patch on a bunch of devices ever since posting it and could not spot any adverse effects.
Regards,
Lucas
Quoted 99 lines
Quoted 87 lines
---
?arch/arm/kernel/smp_twd.c | 31 +++++++++++++++++++++++++++++-- ?1 file changed, 29 insertions(+), 2 deletions(-)arch/arm/kernel/smp_twd.c +0
-0@@ -32,6 +32,8 @@ static struct clk *twd_clk; ?static unsigned long twd_timer_rate; ?static DEFINE_PER_CPU(bool, percpu_setup_called);?
arch/arm/kernel/smp_twd.c +2
-0+static cpumask_var_t active_twd_mask; +?static struct
clock_event_device__percpu*twd_evt; ?static unsigned inttwd_features=Quoted 1 line
?
CLOCK_EVT_FEAT_PERIODIC|CLOCK_EVT_FEAT_ONESHOT;arch/arm/kernel/smp_twd.c +0
-0@@ -39,12 +41,24 @@ static int twd_ppi;?
?static inttwd_shutdown(struct clock_event_device *clk)?{arch/arm/kernel/smp_twd.c static int twd_ppi; · line 44
Quoted 1 line
arch/arm/kernel/smp_twd.c +1
-0+cpumask_clear_cpu (smp_processor_id (), active_twd_mask);+
Quoted 2 lines
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?
writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);? return 0;
?}
?
?static inttwd_set_oneshot(struct clock_event_device *clk)?{Review
Quoted 1 line
(quoted diff) +1
-0+ cpumask_set_cpu(smp_processor_id(), active_twd_mask);+
Review
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(quoted diff) +6
-0+ /* + ?* When going from shutdown to oneshot we might have missed some + ?* frequency updates if the CPU was sleeping. Make sure to update + ?* the timer frequency with the current rate. + ?*/ + if (clockevent_state_shutdown(clk))(quoted diff) +1
-0+ clockevents_update_freq(clk, twd_timer_rate);+
Quoted 3 lines
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? /* period set, and timer enabled in '
next_event' hook */
? writel_relaxed(TWD_TIMER_CONTROL_IT_ENABLE |TWD_TIMER_CONTROL_ONESHOT,? ???????twd_base +
TWD_TIMER_CONTROL);arch/arm/kernel/smp_twd.c +0
-0@@ -57,6 +71,16 @@ static int twd_set_periodic(struct clock_event_device *clk)Quoted 2 lines
Quoted 1 line
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? ?????TWD_TIMER_CONTROL_IT_ENABLE |
? ?????TWD_TIMER_CONTROL_PERIODIC;
?
Review
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(quoted diff) +1
-0+ cpumask_set_cpu(smp_processor_id(), active_twd_mask);+
Review
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(quoted diff) +6
-0+ /* + ?* When going from shutdown to periodic we might have missed some + ?* frequency updates if the CPU was sleeping. Make sure to update + ?* the timer frequency with the current rate. + ?*/ + if (clockevent_state_shutdown(clk))(quoted diff) +1
-0+ clockevents_update_freq(clk, twd_timer_rate);+
Quoted 3 lines
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? writel_relaxed(DIV_ROUND_CLOSEST(twd_timer_rate, HZ),
? ???????twd_base +TWD_TIMER_LOAD);?
writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL);arch/arm/kernel/smp_twd.c +0
-0@@ -124,8 +148,8 @@ static int twd_rate_change(struct notifier_block *nb,Review
Quoted 7 lines
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? ?* changing cpu.
? ?*/
? if (flags ==POST_RATE_CHANGE)arch/arm/kernel/smp_twd.c +1
-2- on_each_cpu(twd_update_frequency, - ??(void *)&cnd->new_rate, 1); + on_each_cpu_mask(active_twd_mask, twd_update_frequency,(quoted diff) +1
-0+ ?(void *)&cnd->new_rate, 1);?
Quoted 1 line
? return
NOTIFY_OK;?}
arch/arm/kernel/smp_twd.c +0
-0@@ -326,6 +350,9 @@ static int __init twd_local_timer_common_register(struct device_node *np) ?{ > ? int err;?
Quoted 7 lines
arch/arm/kernel/smp_twd.c static int __init twd_local_timer_common_register(struct device_node *np) · line 354
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arch/arm/kernel/smp_twd.c +1
-0+if (!zalloc_cpumask_var (&active_twd_mask,GFP_KERNEL ))arch/arm/kernel/smp_twd.c +1
-0+return -ENOMEM ;+
Quoted 3 lines
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?
twd_evt=alloc_percpu(struct clock_event_device);
? if (!twd_evt) {? err =
-ENOMEM;_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
PATCH 1/1 arm/twd: avoid waking deeply sleeping CPUs for rate change notifier
Quoted 17 lines · Lucas Stach
Hi again,
Am Montag, den 11.06.2018, 18:16 +0200 schrieb Lucas Stach:
Quoted 14 lines
Hi all,
Am Dienstag, den 17.04.2018, 12:46 +0200 schrieb Lucas Stach:
Quoted 10 lines
The current clock notifier sends an IPI to all CPUs, even if they are in deep sleep state with the local timer disabled and switched to tick broadcast. This needlessly cuts the CPU sleep times, as nothing is gained from updating a disabled TWDs rate.
Keep track of the enabled TWDs and only send an IPI to those CPUs with an active local timer. As disabled TWDs may now miss a CPU frequency update we need to make sure to refresh the rate on re-enabling of the timer.
Signed-off-by Lucas Stach <[email protected]>
Quoted 8 lines
Quoted 3 lines
I would appreciate some feedback to this patch.
FWIW, I've been running some systems with this patch applied for quite some time now with no issues spotted so far.Can I persuade anyone to take a look at this?
It's been some months since I've posted this and haven't got any feedback so far. I'm running this patch on a bunch of devices ever since posting it and could not spot any adverse effects.
At the first glance, feature and code looks for me.
-- Daniel
Signature · 5 lines
<http://www.linaro.org/> Linaro.org ? Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
Russell King - ARM Linux
maintainerPATCH 1/1 arm/twd: avoid waking deeply sleeping CPUs for rate change notifier
In reply to Lucas StachQuoted 17 lines · Lucas Stach
Hi again,
Am Montag, den 11.06.2018, 18:16 +0200 schrieb Lucas Stach:
Quoted 14 lines
Hi all,
Am Dienstag, den 17.04.2018, 12:46 +0200 schrieb Lucas Stach:
Quoted 10 lines
The current clock notifier sends an IPI to all CPUs, even if they are in deep sleep state with the local timer disabled and switched to tick broadcast. This needlessly cuts the CPU sleep times, as nothing is gained from updating a disabled TWDs rate.
Keep track of the enabled TWDs and only send an IPI to those CPUs with an active local timer. As disabled TWDs may now miss a CPU frequency update we need to make sure to refresh the rate on re-enabling of the timer.
Signed-off-by Lucas Stach <[email protected]>
Quoted 8 lines
Quoted 3 lines
I would appreciate some feedback to this patch.
FWIW, I've been running some systems with this patch applied for quite some time now with no issues spotted so far.Can I persuade anyone to take a look at this?
It's been some months since I've posted this and haven't got any feedback so far. I'm running this patch on a bunch of devices ever since posting it and could not spot any adverse effects.
This, quite simply, needs review by kernel/time people, especially given the potential recursion setup by adding calls to clockevents_update_freq() from within methods that this function _may_ call.
For example, if the current state is shutdown, and clockevents_switch_state() is called to set periodic mode, __clockevents_switch_state() will be called to set periodic mode. The current mode will be shutdown. We'll call twd_set_periodic(), which will then call into clockevents_update_freq().
If tick_broadcast_update_freq() returns -ENODEV (I don't know under what situation that occurs), then we'll call __clockevents_update_freq(). This currently will avoid calling __clockevents_switch_state() but only because the current mode is not marked as periodic yet.
If that changes (either by marking it periodic earlier, or __clockevents_update_freq() changes), then we get a situation where we'll call back into twd_set_periodic().
Then there's the ordering issues - what if we're switching to one-shot mode, does this mean we could get something like:
- set one-shot mode
- clockevents_update_freq
- set next event
- set stale next event
So, I can't review this patch without spending a lot of time reading and understanding the kernel/time code. It would be way better if someone who does understand that code (iow, a maintainer of that code) looked at this patch.
Quoted 104 lines
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---
?arch/arm/kernel/smp_twd.c | 31 +++++++++++++++++++++++++++++-- ?1 file changed, 29 insertions(+), 2 deletions(-)arch/arm/kernel/smp_twd.c +0
-0@@ -32,6 +32,8 @@ static struct clk *twd_clk; ?static unsigned long twd_timer_rate; ?static DEFINE_PER_CPU(bool, percpu_setup_called);?
arch/arm/kernel/smp_twd.c +2
-0+static cpumask_var_t active_twd_mask; +?static struct
clock_event_device__percpu*twd_evt; ?static unsigned inttwd_features=Quoted 1 line
?
CLOCK_EVT_FEAT_PERIODIC|CLOCK_EVT_FEAT_ONESHOT;arch/arm/kernel/smp_twd.c +0
-0@@ -39,12 +41,24 @@ static int twd_ppi;?
?static inttwd_shutdown(struct clock_event_device *clk)?{arch/arm/kernel/smp_twd.c static int twd_ppi; · line 44
Quoted 1 line
arch/arm/kernel/smp_twd.c +1
-0+cpumask_clear_cpu (smp_processor_id (), active_twd_mask);+
Quoted 2 lines
Quoted 1 line
Quoted 1 line
Quoted 1 line
?
writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);? return 0;
?}
?
?static inttwd_set_oneshot(struct clock_event_device *clk)?{Review
Quoted 1 line
(quoted diff) +1
-0+ cpumask_set_cpu(smp_processor_id(), active_twd_mask);+
Review
Quoted 7 lines
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(quoted diff) +6
-0+ /* + ?* When going from shutdown to oneshot we might have missed some + ?* frequency updates if the CPU was sleeping. Make sure to update + ?* the timer frequency with the current rate. + ?*/ + if (clockevent_state_shutdown(clk))(quoted diff) +1
-0+ clockevents_update_freq(clk, twd_timer_rate);+
Quoted 3 lines
Quoted 2 lines
Quoted 2 lines
Quoted 2 lines
? /* period set, and timer enabled in '
next_event' hook */
? writel_relaxed(TWD_TIMER_CONTROL_IT_ENABLE |TWD_TIMER_CONTROL_ONESHOT,? ???????twd_base +
TWD_TIMER_CONTROL);arch/arm/kernel/smp_twd.c +0
-0@@ -57,6 +71,16 @@ static int twd_set_periodic(struct clock_event_device *clk)Quoted 2 lines
Quoted 1 line
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? ?????TWD_TIMER_CONTROL_IT_ENABLE |
? ?????TWD_TIMER_CONTROL_PERIODIC;
?
Review
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(quoted diff) +1
-0+ cpumask_set_cpu(smp_processor_id(), active_twd_mask);+
Review
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(quoted diff) +6
-0+ /* + ?* When going from shutdown to periodic we might have missed some + ?* frequency updates if the CPU was sleeping. Make sure to update + ?* the timer frequency with the current rate. + ?*/ + if (clockevent_state_shutdown(clk))(quoted diff) +1
-0+ clockevents_update_freq(clk, twd_timer_rate);+
Quoted 3 lines
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? writel_relaxed(DIV_ROUND_CLOSEST(twd_timer_rate, HZ),
? ???????twd_base +TWD_TIMER_LOAD);?
writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL);arch/arm/kernel/smp_twd.c +0
-0@@ -124,8 +148,8 @@ static int twd_rate_change(struct notifier_block *nb,Review
Quoted 7 lines
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? ?* changing cpu.
? ?*/
? if (flags ==POST_RATE_CHANGE)arch/arm/kernel/smp_twd.c +1
-2- on_each_cpu(twd_update_frequency, - ??(void *)&cnd->new_rate, 1); + on_each_cpu_mask(active_twd_mask, twd_update_frequency,(quoted diff) +1
-0+ ?(void *)&cnd->new_rate, 1);?
Quoted 1 line
? return
NOTIFY_OK;?}
arch/arm/kernel/smp_twd.c +0
-0@@ -326,6 +350,9 @@ static int __init twd_local_timer_common_register(struct device_node *np) ?{ > ? int err;?
arch/arm/kernel/smp_twd.c static int __init twd_local_timer_common_register(struct device_node *np) · line 354
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arch/arm/kernel/smp_twd.c +1
-0+if (!zalloc_cpumask_var (&active_twd_mask,GFP_KERNEL ))arch/arm/kernel/smp_twd.c +1
-0+return -ENOMEM ;+
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?
twd_evt=alloc_percpu(struct clock_event_device);
? if (!twd_evt) {? err =
-ENOMEM;_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel at lists.infradead.org
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Signature · 3 lines
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up
PATCH 1/1 arm/twd: avoid waking deeply sleeping CPUs for rate change notifier
In reply to Lucas StachQuoted 17 lines · Lucas Stach
Hi again,
Am Montag, den 11.06.2018, 18:16 +0200 schrieb Lucas Stach:
Quoted 14 lines
Hi all,
Am Dienstag, den 17.04.2018, 12:46 +0200 schrieb Lucas Stach:
Quoted 10 lines
The current clock notifier sends an IPI to all CPUs, even if they are in deep sleep state with the local timer disabled and switched to tick broadcast. This needlessly cuts the CPU sleep times, as nothing is gained from updating a disabled TWDs rate.
Keep track of the enabled TWDs and only send an IPI to those CPUs with an active local timer. As disabled TWDs may now miss a CPU frequency update we need to make sure to refresh the rate on re-enabling of the timer.
Signed-off-by Lucas Stach <[email protected]>
Quoted 8 lines
Quoted 3 lines
I would appreciate some feedback to this patch.
FWIW, I've been running some systems with this patch applied for quite some time now with no issues spotted so far.Can I persuade anyone to take a look at this?
It's been some months since I've posted this and haven't got any feedback so far. I'm running this patch on a bunch of devices ever since posting it and could not spot any adverse effects.
Hi Lucas,
can you resend this patch (keeping the current recipient) but adding Thomas Gleixner and John Stultz, the maintainer of the time core framework.
Thanks
-- Daniel
Signature · 5 lines
<http://www.linaro.org/> Linaro.org ? Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
PATCH 1/1 arm/twd: avoid waking deeply sleeping CPUs for rate change notifier
In reply to Lucas StachOn Tue, 2018-04-17 at 12:46 +0200, Lucas Stach wrote:
[...]
arch/arm/kernel/smp_twd.c static int __init twd_local_timer_common_register(struct device_node *np) · line 358
Quoted 10 lines
arch/arm/kernel/smp_twd.c +3
-0@@ -326,6 +350,9 @@ static int __init twd_local_timer_common_register(struct device_node *np) {int err; +if (!zalloc_cpumask_var (&active_twd_mask,GFP_KERNEL )) +return -ENOMEM ; + twd_evt = alloc_percpu(struct clock_event_device);if (!twd_evt) { err = -ENOMEM ;
This could free_cpumask_var(active_twd_mask) in the error path.
regards
Philipp