From: skannan@codeaurora.org (Saravana Kannan)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 3/5] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend
Date: Thu, 24 Jul 2014 18:07:26 -0700 [thread overview]
Message-ID: <1406250448-470-4-git-send-email-skannan@codeaurora.org> (raw)
In-Reply-To: <1406250448-470-1-git-send-email-skannan@codeaurora.org>
This patch simplifies a lot of the hotplug/suspend code by not
adding/removing/moving the policy/sysfs/kobj during hotplug and just leaves
the cpufreq directory and policy in place irrespective of whether the CPUs
are ONLINE/OFFLINE.
Leaving the policy, sysfs and kobject in place also brings these additional
benefits:
* Faster suspend/resume
* Faster hotplug
* Sysfs file permissions maintained across hotplug
* Policy settings and governor tunables maintained across hotplug
* Cpufreq stats would be maintained across hotplug for all CPUs and can be
queried even after CPU goes OFFLINE
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
---
drivers/cpufreq/cpufreq.c | 83 ++++++++++++++++-------------------------------
1 file changed, 28 insertions(+), 55 deletions(-)
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index af4f291..d9fc6e5 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -865,7 +865,7 @@ static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
unsigned int j;
int ret = 0;
- for_each_cpu(j, policy->cpus) {
+ for_each_cpu(j, policy->related_cpus) {
struct device *cpu_dev;
if (j == policy->kobj_cpu)
@@ -968,7 +968,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
int ret = 0;
unsigned long flags;
- if (has_target()) {
+ if (cpumask_weight(policy->cpus) && has_target()) {
ret = __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
if (ret) {
pr_err("%s: Failed to stop governor\n", __func__);
@@ -997,7 +997,7 @@ static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
}
}
- return sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
+ return 0;
}
#endif
@@ -1100,9 +1100,6 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
struct cpufreq_policy *policy;
unsigned long flags;
bool recover_policy = cpufreq_suspended;
-#ifdef CONFIG_HOTPLUG_CPU
- struct cpufreq_policy *tpolicy;
-#endif
if (cpu_is_offline(cpu))
return 0;
@@ -1113,28 +1110,22 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
/* check whether a different CPU already registered this
* CPU because it is in the same boat. */
policy = cpufreq_cpu_get(cpu);
- if (unlikely(policy)) {
+ if (policy) {
+ if (!cpumask_test_cpu(cpu, policy->cpus))
+ ret = cpufreq_add_policy_cpu(policy, cpu, dev);
+ else
+ ret = 0;
cpufreq_cpu_put(policy);
- return 0;
+ return ret;
}
#endif
if (!down_read_trylock(&cpufreq_rwsem))
return 0;
-#ifdef CONFIG_HOTPLUG_CPU
- /* Check if this cpu was hot-unplugged earlier and has siblings */
- read_lock_irqsave(&cpufreq_driver_lock, flags);
- list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
- if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
- read_unlock_irqrestore(&cpufreq_driver_lock, flags);
- ret = cpufreq_add_policy_cpu(tpolicy, cpu, dev);
- up_read(&cpufreq_rwsem);
- return ret;
- }
- }
- read_unlock_irqrestore(&cpufreq_driver_lock, flags);
-#endif
+ /* If we get this far, this is the first time we are adding the
+ * policy */
+ recover_policy = false;
/*
* Restore the saved policy when doing light-weight init and fall back
@@ -1189,7 +1180,7 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
down_write(&policy->rwsem);
write_lock_irqsave(&cpufreq_driver_lock, flags);
- for_each_cpu(j, policy->cpus)
+ for_each_cpu(j, policy->related_cpus)
per_cpu(cpufreq_cpu_data, j) = policy;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
@@ -1274,7 +1265,7 @@ static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
err_out_unregister:
err_get_freq:
write_lock_irqsave(&cpufreq_driver_lock, flags);
- for_each_cpu(j, policy->cpus)
+ for_each_cpu(j, policy->related_cpus)
per_cpu(cpufreq_cpu_data, j) = NULL;
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
@@ -1340,21 +1331,15 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
struct subsys_interface *sif)
{
unsigned int cpu = dev->id, cpus;
- int new_cpu, ret;
+ int new_cpu, ret = 0;
unsigned long flags;
struct cpufreq_policy *policy;
pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
- write_lock_irqsave(&cpufreq_driver_lock, flags);
-
+ read_lock_irqsave(&cpufreq_driver_lock, flags);
policy = per_cpu(cpufreq_cpu_data, cpu);
-
- /* Save the policy somewhere when doing a light-weight tear-down */
- if (cpufreq_suspended)
- per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
-
- write_unlock_irqrestore(&cpufreq_driver_lock, flags);
+ read_unlock_irqrestore(&cpufreq_driver_lock, flags);
if (!policy) {
pr_debug("%s: No cpu_data found\n", __func__);
@@ -1369,24 +1354,15 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
}
}
- if (!cpufreq_driver->setpolicy)
- strncpy(per_cpu(cpufreq_cpu_governor, cpu),
- policy->governor->name, CPUFREQ_NAME_LEN);
-
down_read(&policy->rwsem);
cpus = cpumask_weight(policy->cpus);
up_read(&policy->rwsem);
- if (cpu != policy->cpu) {
- sysfs_remove_link(&dev->kobj, "cpufreq");
- } else if (cpus > 1) {
- new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu);
- if (new_cpu >= 0) {
- update_policy_cpu(policy, new_cpu);
-
- if (!cpufreq_suspended)
- pr_debug("%s: policy Kobject moved to cpu: %d from: %d\n",
- __func__, new_cpu, cpu);
+ if (cpus > 1) {
+ if (cpu == policy->cpu) {
+ new_cpu = cpumask_any_but(policy->cpus, cpu);
+ if (new_cpu >= 0)
+ update_policy_cpu(policy, new_cpu);
}
} else if (cpufreq_driver->stop_cpu && cpufreq_driver->setpolicy) {
cpufreq_driver->stop_cpu(policy);
@@ -1431,6 +1407,9 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
cpus = cpumask_weight(policy->cpus);
up_read(&policy->rwsem);
+ if (cpu != policy->kobj_cpu)
+ sysfs_remove_link(&dev->kobj, "cpufreq");
+
/* If cpu is last user of policy, free policy */
if (cpus == 0) {
if (has_target()) {
@@ -1475,12 +1454,10 @@ static int __cpufreq_remove_dev_finish(struct device *dev,
static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
{
unsigned int cpu = dev->id;
- int ret;
-
- if (cpu_is_offline(cpu))
- return 0;
+ int ret = 0;
- ret = __cpufreq_remove_dev_prepare(dev, sif);
+ if (cpu_online(cpu))
+ ret = __cpufreq_remove_dev_prepare(dev, sif);
if (!ret)
ret = __cpufreq_remove_dev_finish(dev, sif);
@@ -2307,10 +2284,6 @@ static int cpufreq_cpu_callback(struct notifier_block *nfb,
__cpufreq_remove_dev_prepare(dev, NULL);
break;
- case CPU_POST_DEAD:
- __cpufreq_remove_dev_finish(dev, NULL);
- break;
-
case CPU_DOWN_FAILED:
__cpufreq_add_dev(dev, NULL);
break;
--
1.8.2.1
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation
next prev parent reply other threads:[~2014-07-25 1:07 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-10 2:37 [PATCH] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend Saravana Kannan
2014-07-11 4:18 ` [PATCH v2] " Saravana Kannan
2014-07-11 6:19 ` Viresh Kumar
2014-07-11 9:59 ` skannan at codeaurora.org
2014-07-11 10:07 ` skannan at codeaurora.org
2014-07-11 10:52 ` Viresh Kumar
2014-07-12 2:44 ` Saravana Kannan
2014-07-14 6:09 ` Viresh Kumar
2014-07-14 19:08 ` Saravana Kannan
2014-07-15 4:35 ` Viresh Kumar
2014-07-15 5:36 ` Saravana Kannan
2014-07-15 5:52 ` Viresh Kumar
2014-07-15 6:58 ` Srivatsa S. Bhat
2014-07-15 17:35 ` skannan at codeaurora.org
2014-07-16 7:44 ` Srivatsa S. Bhat
2014-07-16 5:44 ` Viresh Kumar
2014-07-16 7:49 ` Srivatsa S. Bhat
2014-07-12 3:06 ` Saravana Kannan
2014-07-14 6:13 ` Viresh Kumar
2014-07-14 19:10 ` Saravana Kannan
2014-07-11 7:43 ` Srivatsa S. Bhat
2014-07-11 10:02 ` skannan at codeaurora.org
2014-07-15 22:47 ` [PATCH v3 0/2] Simplify hotplug/suspend handling Saravana Kannan
2014-07-15 22:47 ` [PATCH v3 1/2] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend Saravana Kannan
2014-07-16 0:28 ` Saravana Kannan
2014-07-16 8:30 ` Viresh Kumar
2014-07-16 19:19 ` Saravana Kannan
2014-07-16 8:24 ` Viresh Kumar
2014-07-16 11:16 ` Srivatsa S. Bhat
2014-07-16 13:13 ` Viresh Kumar
2014-07-16 18:04 ` Srivatsa S. Bhat
2014-07-16 19:56 ` Saravana Kannan
2014-07-17 5:51 ` Viresh Kumar
2014-07-16 19:56 ` Saravana Kannan
2014-07-17 5:35 ` Viresh Kumar
2014-07-18 3:25 ` Saravana Kannan
2014-07-18 4:19 ` Viresh Kumar
2014-07-16 20:25 ` Saravana Kannan
2014-07-16 21:45 ` Saravana Kannan
2014-07-17 6:24 ` Viresh Kumar
2014-07-16 14:29 ` Dirk Brandewie
2014-07-16 15:28 ` Viresh Kumar
2014-07-16 19:42 ` Saravana Kannan
2014-07-15 22:47 ` [PATCH v3 2/2] cpufreq: Simplify and fix mutual exclusion with hotplug Saravana Kannan
2014-07-16 8:48 ` Viresh Kumar
2014-07-16 19:34 ` Saravana Kannan
2014-07-25 1:07 ` [PATCH v4 0/5] Simplify hotplug/suspend handling Saravana Kannan
2014-07-25 1:07 ` [PATCH v4 1/5] cpufreq: Don't wait for CPU to going offline to restart governor Saravana Kannan
2014-07-31 20:47 ` Saravana Kannan
2014-07-25 1:07 ` [PATCH v4 2/5] cpufreq: Keep track of which CPU owns the kobj/sysfs nodes separately Saravana Kannan
2014-08-07 9:02 ` Viresh Kumar
2014-07-25 1:07 ` Saravana Kannan [this message]
2014-07-31 21:56 ` [PATCH v4 3/5] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend Rafael J. Wysocki
2014-07-31 22:15 ` Saravana Kannan
2014-07-31 23:48 ` Saravana Kannan
2014-08-07 10:51 ` Viresh Kumar
2014-08-12 9:17 ` Viresh Kumar
2014-08-07 10:48 ` Viresh Kumar
2014-08-11 22:13 ` Saravana Kannan
2014-08-12 8:51 ` Viresh Kumar
2014-07-25 1:07 ` [PATCH v4 4/5] cpufreq: Properly handle physical CPU hot-add/hot-remove Saravana Kannan
2014-08-07 11:02 ` Viresh Kumar
2014-08-11 22:15 ` Saravana Kannan
2014-07-25 1:07 ` [PATCH v4 5/5] cpufreq: Delete dead code related to policy save/restore Saravana Kannan
2014-08-07 11:06 ` Viresh Kumar
2014-07-29 5:52 ` [PATCH v4 0/5] Simplify hotplug/suspend handling skannan at codeaurora.org
2014-07-30 0:29 ` Rafael J. Wysocki
2014-07-31 20:25 ` Saravana Kannan
2014-08-07 6:04 ` skannan at codeaurora.org
2014-10-16 8:53 ` Viresh Kumar
2014-10-23 21:41 ` Saravana Kannan
2014-07-16 22:02 ` [PATCH] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend Rafael J. Wysocki
2014-07-16 22:35 ` Saravana Kannan
2014-07-24 3:02 ` Saravana Kannan
2014-07-24 5:04 ` Viresh Kumar
2014-07-24 9:12 ` skannan at codeaurora.org
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1406250448-470-4-git-send-email-skannan@codeaurora.org \
--to=skannan@codeaurora.org \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).