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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Jacob Shin <jacob.shin@amd.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
	cpufreq@vger.kernel.org, linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org,
	robin.randhawa@arm.com, Steve.Bannister@arm.com,
	Liviu.Dudau@arm.com, charles.garcia-tobin@arm.com,
	Arvind Chauhan <Arvind.Chauhan@arm.com>
Subject: Re: [PATCH V3 2/4] cpufreq: governor: Implement per policy instances of governors
Date: Wed, 27 Mar 2013 01:02:15 +0530	[thread overview]
Message-ID: <CAKohpons4Tr8F2RuRGCxbOFmJaK9YbAafV-3v6=cijRupe2hUA@mail.gmail.com> (raw)
In-Reply-To: <20130326152059.GA1698@jshin-Toonie>

[-- Attachment #1: Type: text/plain, Size: 6072 bytes --]

On 26 March 2013 20:50, Jacob Shin <jacob.shin@amd.com> wrote:
> Hi, latest bleeding-edge is spewing this out on boot:
>
> [    3.585157] ------------[ cut here ]------------
> [    3.592227] WARNING: at fs/sysfs/dir.c:536 sysfs_add_one+0xc8/0x100()
> [    3.599521] Hardware name: Dinar
> [    3.606878] sysfs: cannot create duplicate filename '/devices/system/cpu/cpufreq/ondemand'
> [    3.614634] Modules linked in:
> [    3.622382] Pid: 1, comm: swapper/0 Not tainted 3.9.0-rc4+ #7
> [    3.630305] Call Trace:
> [    3.638251]  [<ffffffff810589cf>] warn_slowpath_common+0x7f/0xc0
> [    3.646435]  [<ffffffff81058ac6>] warn_slowpath_fmt+0x46/0x50
> [    3.654586]  [<ffffffff8133e2f0>] ? strlcat+0x60/0x80
> [    3.662765]  [<ffffffff811fe7d8>] sysfs_add_one+0xc8/0x100
> [    3.670977]  [<ffffffff811fe9cc>] create_dir+0x7c/0xd0
> [    3.679239]  [<ffffffff811fecaf>] sysfs_create_subdir+0x1f/0x30
> [    3.687601]  [<ffffffff812006c4>] internal_create_group+0x64/0x210
> [    3.696098]  [<ffffffff812008a3>] sysfs_create_group+0x13/0x20
> [    3.704700]  [<ffffffff816bf800>] cpufreq_governor_dbs+0x400/0x590
> [    3.713401]  [<ffffffff816bdc37>] od_cpufreq_governor_dbs+0x17/0x20
> [    3.722191]  [<ffffffff816bb437>] __cpufreq_governor+0x47/0xc0
> [    3.731071]  [<ffffffff816bb94d>] __cpufreq_set_policy+0x19d/0x1b0
> [    3.739968]  [<ffffffff816bca89>] cpufreq_add_dev_interface+0x259/0x2b0
> [    3.748960]  [<ffffffff813cdce6>] ? acpi_processor_get_performance_info+0x21c/0x452
> [    3.758099]  [<ffffffff816bc210>] ? cpufreq_update_policy+0x130/0x130
> [    3.767366]  [<ffffffff816bce90>] cpufreq_add_dev+0x3b0/0x4d0
> [    3.776659]  [<ffffffff821579d4>] ? cpufreq_gov_dbs_init+0x12/0x12
> [    3.785985]  [<ffffffff814e6a39>] subsys_interface_register+0x89/0xd0
> [    3.795452]  [<ffffffff816baf5e>] cpufreq_register_driver+0x8e/0x180
> [    3.804919]  [<ffffffff82157aca>] acpi_cpufreq_init+0xf6/0x1f8
> [    3.814360]  [<ffffffff814f5030>] ? set_trace_device+0x80/0x80
> [    3.823558]  [<ffffffff8100206f>] do_one_initcall+0x3f/0x170
> [    3.832476]  [<ffffffff8211b00a>] kernel_init_freeable+0x13e/0x1cd
> [    3.841131]  [<ffffffff8211a88e>] ? do_early_param+0x86/0x86
> [    3.849506]  [<ffffffff817f4c20>] ? rest_init+0x80/0x80
> [    3.857557]  [<ffffffff817f4c2e>] kernel_init+0xe/0xf0
> [    3.865260]  [<ffffffff8181edec>] ret_from_fork+0x7c/0xb0
> [    3.872886]  [<ffffffff817f4c20>] ? rest_init+0x80/0x80
> [    3.880456] ---[ end trace 1a5c6247c6d9b0ac ]---
> [    3.888201] ------------[ cut here ]------------
>
> This warning is repeated for number of cpus - 1 times.
>
> And when I do:
>
> $ cat /sys/devices/system/cpu/cpufreq/ondemand/up_threshold
>
> [  489.103388] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
> [  489.112064] IP: [<ffffffff816be02c>] show_up_threshold+0x1c/0x30
> [  489.120511] PGD a285e6067 PUD a27085067 PMD 0
> [  489.128690] Oops: 0000 [#1] SMP
> [  489.136521] Modules linked in:
> [  489.144134] CPU 15
> [  489.144229] Pid: 1565, comm: cat Tainted: G        W    3.9.0-rc4+ #7 AMD Dinar/Dinar
> [  489.159654] RIP: 0010:[<ffffffff816be02c>]  [<ffffffff816be02c>] show_up_threshold+0x1c/0x30
> [  489.167864] RSP: 0018:ffff880423859e88  EFLAGS: 00010246
> [  489.176043] RAX: 0000000000000000 RBX: ffff880a271188c0 RCX: ffffffff81a41810
> [  489.184372] RDX: 0000000000000000 RSI: ffffffff81e02dae RDI: ffffffff820d7860
> [  489.184373] RBP: ffff880423859e88 R08: ffffea0028b6df80 R09: 00000000001f05b8
> [  489.184374] R10: 0000000000001b97 R11: 0000000000000246 R12: ffff880423859f50
> [  489.184374] R13: 0000000000008000 R14: ffff880a271188a0 R15: ffff8804251aa070
> [  489.184377] FS:  00007f3278b31700(0000) GS:ffff880a2fcc0000(0000) knlGS:0000000000000000
> [  489.184378] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  489.184378] CR2: 0000000000000010 CR3: 0000000a2db82000 CR4: 00000000000407e0
> [  489.184380] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [  489.184381] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> [  489.184382] Process cat (pid: 1565, threadinfo ffff880423858000, task ffff880424805c00)
> [  489.184382] Stack:
> [  489.184389]  ffff880423859e98 ffffffff8133814f ffff880423859ef8 ffffffff811fd62a
> [  489.184394]  000000002bf67be2 ffff8808260b7a80 ffffffff81a41810 00000000012c8000
> [  489.184399]  ffff880423859ef8 0000000000008000 00000000012c8000 ffff880423859f50
> [  489.184400] Call Trace:
> [  489.184406]  [<ffffffff8133814f>] kobj_attr_show+0xf/0x30
> [  489.184411]  [<ffffffff811fd62a>] sysfs_read_file+0xaa/0x190
> [  489.184415]  [<ffffffff81187e30>] vfs_read+0xb0/0x180
> [  489.184418]  [<ffffffff81187f52>] sys_read+0x52/0xa0
> [  489.184422]  [<ffffffff8181a7fe>] ? do_page_fault+0xe/0x10
> [  489.184426]  [<ffffffff8181ee99>] system_call_fastpath+0x16/0x1b
> [  489.184441] Code: 52 08 e8 78 2c c8 ff 5d 48 98 c3 0f 1f 40 00 66 66 66 66 90 55 48 8b 57 70 48 89 f0 48 89 c7 48 c7 c6 ae 2d e0 81 31 c0 48 89 e5 <48> 8b 52 10 8b 52 0c e8 48 2c c8 ff 5d 48 98 c3 0f 1f 40 00 66
> [  489.184443] RIP  [<ffffffff816be02c>] show_up_threshold+0x1c/0x30
> [  489.184443]  RSP <ffff880423859e88>
> [  489.184444] CR2: 0000000000000010
> [  489.184507] ---[ end trace 1a5c6247c6d9b0c3 ]---
>
> Any ideas?

Yes, i believe i have enough idea about it :)

There are two kind of systems i know:
1 - Single group of cpus controlled by a single clock line,
     i.e. only one policy instance at any time
2 - multipolicy systems where we have more than one group of cpus
     and every group have one clock line.

For the second case also there are two cases:
2.1 - support have_multiple_policies (i.e. have separate instance of governor
        for each policy struct)
2.2 - doesn't support have_multiple_policies

The last one (2.2) is broken with my patch and attached is the fix. I
have tested
it on my Lenovo Thinkpad which is more like 2.2 case.

cat of cpufreq/ondemand/** is still broken and i am too tired of
fixing it now...
Its already midnight here 01:01 AM.

--
viresh

[-- Attachment #2: 0001-fixup-cpufreq-governor-Implement-per-policy-instance.patch --]
[-- Type: application/octet-stream, Size: 7337 bytes --]

From c95ca544325f40f55858e02526d0bd6a1740480d Mon Sep 17 00:00:00 2001
Message-Id: <c95ca544325f40f55858e02526d0bd6a1740480d.1364322587.git.viresh.kumar@linaro.org>
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: Tue, 26 Mar 2013 23:20:18 +0530
Subject: [PATCH] fixup! cpufreq: governor: Implement per policy instances of
 governors

---
 drivers/cpufreq/cpufreq.c          | 13 +++++++
 drivers/cpufreq/cpufreq_governor.c | 74 +++++++++++++++++++++++++++-----------
 include/linux/cpufreq.h            |  2 ++
 3 files changed, 68 insertions(+), 21 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 8f2a603..3c79025 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -136,6 +136,11 @@ struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
 		return cpufreq_global_kobject;
 }
 
+bool have_multiple_policies(void)
+{
+	return cpufreq_driver->have_multiple_policies;
+}
+
 static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs)
 {
 	struct cpufreq_policy *data;
@@ -1561,6 +1566,13 @@ static int __cpufreq_governor(struct cpufreq_policy *policy,
 						policy->cpu, event);
 	ret = policy->governor->governor(policy, event);
 
+	if (!ret) {
+		if (event == CPUFREQ_GOV_POLICY_INIT)
+			policy->governor->initialized++;
+		else if (event == CPUFREQ_GOV_POLICY_EXIT)
+			policy->governor->initialized--;
+	}
+
 	/* we keep one module reference alive for
 			each CPU governed by this CPU */
 	if ((event != CPUFREQ_GOV_START) || ret)
@@ -1584,6 +1596,7 @@ int cpufreq_register_governor(struct cpufreq_governor *governor)
 
 	mutex_lock(&cpufreq_governor_mutex);
 
+	governor->initialized = 0;
 	err = -EBUSY;
 	if (__find_governor(governor->name) == NULL) {
 		err = 0;
diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index 41e5e56..f29feb4 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -29,6 +29,9 @@
 
 #include "cpufreq_governor.h"
 
+/* Common data for platforms that don't need governor instance per policy */
+struct dbs_data *gdbs_data;
+
 static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
 {
 	u64 idle_time;
@@ -216,10 +219,9 @@ static void set_sampling_rate(struct dbs_data *dbs_data,
 int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 		struct common_dbs_data *cdata, unsigned int event)
 {
-	struct dbs_data *dbs_data = policy->governor_data;
+	struct dbs_data *dbs_data;
 	struct od_cpu_dbs_info_s *od_dbs_info = NULL;
 	struct cs_cpu_dbs_info_s *cs_dbs_info = NULL;
-	struct cs_ops *cs_ops = NULL;
 	struct od_ops *od_ops = NULL;
 	struct od_dbs_tuners *od_tuners = NULL;
 	struct cs_dbs_tuners *cs_tuners = NULL;
@@ -228,11 +230,22 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 	int io_busy = 0;
 	int rc;
 
+	if (have_multiple_policies())
+		dbs_data = policy->governor_data;
+	else
+		dbs_data = gdbs_data;
+
 	WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
 
 	switch (event) {
 	case CPUFREQ_GOV_POLICY_INIT:
-		WARN_ON(dbs_data);
+		if (have_multiple_policies()) {
+			WARN_ON(dbs_data);
+		} else if (dbs_data) {
+			policy->governor_data = dbs_data;
+			return 0;
+		}
+
 		dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
 		if (!dbs_data) {
 			pr_err("%s: POLICY_INIT: kzalloc failed\n", __func__);
@@ -246,6 +259,15 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			kfree(dbs_data);
 			return rc;
 		}
+
+		rc = sysfs_create_group(get_governor_parent_kobj(policy),
+				dbs_data->cdata->attr_group);
+		if (rc) {
+			cdata->exit(dbs_data);
+			kfree(dbs_data);
+			return rc;
+		}
+
 		policy->governor_data = dbs_data;
 
 		/* policy latency is in nS. Convert it to uS first */
@@ -258,10 +280,36 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 				MIN_LATENCY_MULTIPLIER * latency);
 		set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
 					latency * LATENCY_MULTIPLIER));
+
+		if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+			struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
+
+			cpufreq_register_notifier(cs_ops->notifier_block,
+					CPUFREQ_TRANSITION_NOTIFIER);
+		}
+
+		if (!have_multiple_policies())
+			gdbs_data = dbs_data;
+
 		return 0;
 	case CPUFREQ_GOV_POLICY_EXIT:
-		cdata->exit(dbs_data);
-		kfree(dbs_data);
+		if ((policy->governor->initialized == 1) ||
+				have_multiple_policies()) {
+			sysfs_remove_group(get_governor_parent_kobj(policy),
+					dbs_data->cdata->attr_group);
+
+			if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
+				struct cs_ops *cs_ops = dbs_data->cdata->gov_ops;
+
+				cpufreq_register_notifier(cs_ops->notifier_block,
+						CPUFREQ_TRANSITION_NOTIFIER);
+			}
+
+			cdata->exit(dbs_data);
+			kfree(dbs_data);
+			gdbs_data = NULL;
+		}
+
 		policy->governor_data = NULL;
 		return 0;
 	}
@@ -273,7 +321,6 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 		cs_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
 		sampling_rate = cs_tuners->sampling_rate;
 		ignore_nice = cs_tuners->ignore_nice;
-		cs_ops = dbs_data->cdata->gov_ops;
 	} else {
 		od_tuners = dbs_data->tuners;
 		od_dbs_info = dbs_data->cdata->get_cpu_dbs_info_s(cpu);
@@ -307,13 +354,6 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 					     dbs_data->cdata->gov_dbs_timer);
 		}
 
-		rc = sysfs_create_group(get_governor_parent_kobj(policy),
-				dbs_data->cdata->attr_group);
-		if (rc) {
-			mutex_unlock(&dbs_data->mutex);
-			return rc;
-		}
-
 		/*
 		 * conservative does not implement micro like ondemand
 		 * governor, thus we are bound to jiffes/HZ
@@ -322,9 +362,6 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 			cs_dbs_info->down_skip = 0;
 			cs_dbs_info->enable = 1;
 			cs_dbs_info->requested_freq = policy->cur;
-
-			cpufreq_register_notifier(cs_ops->notifier_block,
-					CPUFREQ_TRANSITION_NOTIFIER);
 		} else {
 			od_dbs_info->rate_mult = 1;
 			od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
@@ -349,11 +386,6 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
 		mutex_lock(&dbs_data->mutex);
 		mutex_destroy(&cpu_cdbs->timer_mutex);
 
-		sysfs_remove_group(get_governor_parent_kobj(policy),
-				dbs_data->cdata->attr_group);
-		if (dbs_data->cdata->governor == GOV_CONSERVATIVE)
-			cpufreq_unregister_notifier(cs_ops->notifier_block,
-					CPUFREQ_TRANSITION_NOTIFIER);
 		mutex_unlock(&dbs_data->mutex);
 
 		break;
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 8fe9b10..f253a3e 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -187,6 +187,7 @@ static inline unsigned long cpufreq_scale(unsigned long old, u_int div, u_int mu
 
 struct cpufreq_governor {
 	char	name[CPUFREQ_NAME_LEN];
+	int	initialized;
 	int	(*governor)	(struct cpufreq_policy *policy,
 				 unsigned int event);
 	ssize_t	(*show_setspeed)	(struct cpufreq_policy *policy,
@@ -323,6 +324,7 @@ const char *cpufreq_get_current_driver(void);
 int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu);
 int cpufreq_update_policy(unsigned int cpu);
 struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy);
+bool have_multiple_policies(void);
 
 #ifdef CONFIG_CPU_FREQ
 /* query the current CPU frequency (in kHz). If zero, cpufreq couldn't detect it */
-- 
1.7.12.rc2.18.g61b472e


  reply	other threads:[~2013-03-26 19:32 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-04  7:37 [PATCH V3 0/4] CPUFreq: Implement per policy instances of governors Viresh Kumar
2013-03-04  7:37 ` [PATCH V3 1/4] cpufreq: Add per policy governor-init/exit infrastructure Viresh Kumar
2013-03-04  7:37 ` [PATCH V3 2/4] cpufreq: governor: Implement per policy instances of governors Viresh Kumar
2013-03-20  5:29   ` Viresh Kumar
2013-03-21 23:44     ` Rafael J. Wysocki
2013-03-22  2:20       ` Viresh Kumar
2013-03-22 11:55         ` Rafael J. Wysocki
2013-03-22 11:51           ` Viresh Kumar
2013-03-22 12:11             ` Rafael J. Wysocki
2013-03-22 12:05               ` Viresh Kumar
2013-03-26 15:20       ` Jacob Shin
2013-03-26 19:32         ` Viresh Kumar [this message]
2013-03-26 19:48           ` Jacob Shin
2013-03-27  4:29             ` Viresh Kumar
2013-03-27 10:04               ` Viresh Kumar
2013-03-27 11:35                 ` Viresh Kumar
2013-03-27 14:37                   ` Viresh Kumar
2013-03-04  7:37 ` [PATCH V3 3/4] cpufreq: Get rid of "struct global_attr" Viresh Kumar
2013-03-04  7:37 ` [PATCH V3 4/4] cpufreq: Add Kconfig option to enable/disable have_multiple_policies Viresh Kumar
2013-03-11 23:38   ` Rafael J. Wysocki
2013-03-12  0:55     ` Viresh Kumar
2013-03-13 21:41       ` Rafael J. Wysocki
2013-03-14  3:09         ` Viresh Kumar
2013-03-20  0:20           ` Rafael J. Wysocki
2013-03-20  4:23             ` Viresh Kumar
2013-03-20  5:16               ` Viresh Kumar

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