I'm using this crazy email address because I have problems getting to
linux.intel.com from home, and my work at intel has changed a bit.
This is the first in a 5 part series that attempts to update PM_QOS to
use handles instead of named strings in its kernel api. It seams that
some folks are using pm_qos on hot paths and the overhead of the list
walks and string compares is a problem.
Most of the changes came from [email protected], and I spent some time
cleaning up the API.
Also, I couldn't resist myself in renaming the API's a bit give the fact
that the signatures changed enough that I had to touch all the pm_qos
users anyway. I changed *requirement* to *request* in keeping with the
way PM_QOS really only does best effort. I've felt "requirement" is too
strong a word for the way it works.
If folks would rather me do the function re-naming in a separate patch
set we can do that too.
diffstat:
drivers/acpi/processor_idle.c | 2
drivers/cpuidle/governors/ladder.c | 2
drivers/cpuidle/governors/menu.c | 2
drivers/net/e1000e/netdev.c | 13 +-
drivers/net/igbvf/netdev.c | 5
drivers/net/wireless/ipw2x00/ipw2100.c | 11 +
include/linux/pm_qos_params.h | 14 +-
include/sound/pcm.h | 3
kernel/pm_qos_params.c | 186 ++++++++++++++-------------------
net/mac80211/mlme.c | 2
sound/core/pcm.c | 3
sound/core/pcm_native.c | 12 +-
12 files changed, 117 insertions(+), 138 deletions(-)
Signed-off-by: mark gross <[email protected]>
---
include/linux/pm_qos_params.h | 14 ++--
kernel/pm_qos_params.c | 186 ++++++++++++++++++-----------------------
2 files changed, 90 insertions(+), 110 deletions(-)
diff --git a/include/linux/pm_qos_params.h b/include/linux/pm_qos_params.h
index d74f75e..8ba440e 100644
--- a/include/linux/pm_qos_params.h
+++ b/include/linux/pm_qos_params.h
@@ -14,12 +14,14 @@
#define PM_QOS_NUM_CLASSES 4
#define PM_QOS_DEFAULT_VALUE -1
-int pm_qos_add_requirement(int qos, char *name, s32 value);
-int pm_qos_update_requirement(int qos, char *name, s32 new_value);
-void pm_qos_remove_requirement(int qos, char *name);
+struct pm_qos_request_list;
-int pm_qos_requirement(int qos);
+struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value);
+void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
+ s32 new_value);
+void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req);
-int pm_qos_add_notifier(int qos, struct notifier_block *notifier);
-int pm_qos_remove_notifier(int qos, struct notifier_block *notifier);
+int pm_qos_request(int pm_qos_class);
+int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier);
+int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier);
diff --git a/kernel/pm_qos_params.c b/kernel/pm_qos_params.c
index dfdec52..c2659d0 100644
--- a/kernel/pm_qos_params.c
+++ b/kernel/pm_qos_params.c
@@ -2,7 +2,7 @@
* This module exposes the interface to kernel space for specifying
* QoS dependencies. It provides infrastructure for registration of:
*
- * Dependents on a QoS value : register requirements
+ * Dependents on a QoS value : register requests
* Watchers of QoS value : get notified when target QoS value changes
*
* This QoS design is best effort based. Dependents register their QoS needs.
@@ -14,14 +14,14 @@
* timeout: usec <-- currently not used.
* throughput: kbs (kilo byte / sec)
*
- * There are lists of pm_qos_objects each one wrapping requirements, notifiers
+ * There are lists of pm_qos_objects each one wrapping requests, notifiers
*
- * User mode requirements on a QOS parameter register themselves to the
+ * User mode requests on a QOS parameter register themselves to the
* subsystem by opening the device node /dev/... and writing there request to
* the node. As long as the process holds a file handle open to the node the
* client continues to be accounted for. Upon file release the usermode
- * requirement is removed and a new qos target is computed. This way when the
- * requirement that the application has is cleaned up when closes the file
+ * request is removed and a new qos target is computed. This way when the
+ * request that the application has is cleaned up when closes the file
* pointer or exits the pm_qos_object will get an opportunity to clean up.
*
* Mark Gross <[email protected]>
@@ -43,25 +43,25 @@
#include <linux/uaccess.h>
/*
- * locking rule: all changes to requirements or notifiers lists
+ * locking rule: all changes to requests or notifiers lists
* or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
* held, taken with _irqsave. One lock to rule them all
*/
-struct requirement_list {
+struct pm_qos_request_list {
struct list_head list;
union {
s32 value;
s32 usec;
s32 kbps;
};
- char *name;
+ int pm_qos_class;
};
static s32 max_compare(s32 v1, s32 v2);
static s32 min_compare(s32 v1, s32 v2);
struct pm_qos_object {
- struct requirement_list requirements;
+ struct pm_qos_request_list requests;
struct blocking_notifier_head *notifiers;
struct miscdevice pm_qos_power_miscdev;
char *name;
@@ -73,7 +73,7 @@ struct pm_qos_object {
static struct pm_qos_object null_pm_qos;
static BLOCKING_NOTIFIER_HEAD(cpu_dma_lat_notifier);
static struct pm_qos_object cpu_dma_pm_qos = {
- .requirements = {LIST_HEAD_INIT(cpu_dma_pm_qos.requirements.list)},
+ .requests = {LIST_HEAD_INIT(cpu_dma_pm_qos.requests.list)},
.notifiers = &cpu_dma_lat_notifier,
.name = "cpu_dma_latency",
.default_value = 2000 * USEC_PER_SEC,
@@ -83,7 +83,7 @@ static struct pm_qos_object cpu_dma_pm_qos = {
static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
static struct pm_qos_object network_lat_pm_qos = {
- .requirements = {LIST_HEAD_INIT(network_lat_pm_qos.requirements.list)},
+ .requests = {LIST_HEAD_INIT(network_lat_pm_qos.requests.list)},
.notifiers = &network_lat_notifier,
.name = "network_latency",
.default_value = 2000 * USEC_PER_SEC,
@@ -94,8 +94,7 @@ static struct pm_qos_object network_lat_pm_qos = {
static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
static struct pm_qos_object network_throughput_pm_qos = {
- .requirements =
- {LIST_HEAD_INIT(network_throughput_pm_qos.requirements.list)},
+ .requests = {LIST_HEAD_INIT(network_throughput_pm_qos.requests.list)},
.notifiers = &network_throughput_notifier,
.name = "network_throughput",
.default_value = 0,
@@ -136,31 +135,34 @@ static s32 min_compare(s32 v1, s32 v2)
}
-static void update_target(int target)
+static void update_target(int pm_qos_class)
{
s32 extreme_value;
- struct requirement_list *node;
+ struct pm_qos_request_list *node;
unsigned long flags;
int call_notifier = 0;
spin_lock_irqsave(&pm_qos_lock, flags);
- extreme_value = pm_qos_array[target]->default_value;
+ extreme_value = pm_qos_array[pm_qos_class]->default_value;
list_for_each_entry(node,
- &pm_qos_array[target]->requirements.list, list) {
- extreme_value = pm_qos_array[target]->comparitor(
+ &pm_qos_array[pm_qos_class]->requests.list, list) {
+ extreme_value = pm_qos_array[pm_qos_class]->comparitor(
extreme_value, node->value);
}
- if (atomic_read(&pm_qos_array[target]->target_value) != extreme_value) {
+ if (atomic_read(&pm_qos_array[pm_qos_class]->target_value) !=
+ extreme_value) {
call_notifier = 1;
- atomic_set(&pm_qos_array[target]->target_value, extreme_value);
- pr_debug(KERN_ERR "new target for qos %d is %d\n", target,
- atomic_read(&pm_qos_array[target]->target_value));
+ atomic_set(&pm_qos_array[pm_qos_class]->target_value,
+ extreme_value);
+ pr_debug(KERN_ERR "new target for qos %d is %d\n", pm_qos_class,
+ atomic_read(&pm_qos_array[pm_qos_class]->target_value));
}
spin_unlock_irqrestore(&pm_qos_lock, flags);
if (call_notifier)
- blocking_notifier_call_chain(pm_qos_array[target]->notifiers,
- (unsigned long) extreme_value, NULL);
+ blocking_notifier_call_chain(
+ pm_qos_array[pm_qos_class]->notifiers,
+ (unsigned long) extreme_value, NULL);
}
static int register_pm_qos_misc(struct pm_qos_object *qos)
@@ -186,125 +188,108 @@ static int find_pm_qos_object_by_minor(int minor)
}
/**
- * pm_qos_requirement - returns current system wide qos expectation
+ * pm_qos_request - returns current system wide qos expectation
* @pm_qos_class: identification of which qos value is requested
*
* This function returns the current target value in an atomic manner.
*/
-int pm_qos_requirement(int pm_qos_class)
+int pm_qos_request(int pm_qos_class)
{
return atomic_read(&pm_qos_array[pm_qos_class]->target_value);
}
-EXPORT_SYMBOL_GPL(pm_qos_requirement);
+EXPORT_SYMBOL_GPL(pm_qos_request);
/**
- * pm_qos_add_requirement - inserts new qos request into the list
+ * pm_qos_add_request - inserts new qos request into the list
* @pm_qos_class: identifies which list of qos request to us
- * @name: identifies the request
* @value: defines the qos request
*
* This function inserts a new entry in the pm_qos_class list of requested qos
* performance characteristics. It recomputes the aggregate QoS expectations
- * for the pm_qos_class of parameters.
+ * for the pm_qos_class of parameters, and returns the pm_qos_request list
+ * element as a handle for use in updating and removal. Call needs to save
+ * this handle for later use.
*/
-int pm_qos_add_requirement(int pm_qos_class, char *name, s32 value)
+struct pm_qos_request_list *pm_qos_add_request(int pm_qos_class, s32 value)
{
- struct requirement_list *dep;
+ struct pm_qos_request_list *dep;
unsigned long flags;
- dep = kzalloc(sizeof(struct requirement_list), GFP_KERNEL);
+ dep = kzalloc(sizeof(struct pm_qos_request_list), GFP_KERNEL);
if (dep) {
if (value == PM_QOS_DEFAULT_VALUE)
dep->value = pm_qos_array[pm_qos_class]->default_value;
else
dep->value = value;
- dep->name = kstrdup(name, GFP_KERNEL);
- if (!dep->name)
- goto cleanup;
+ dep->pm_qos_class = pm_qos_class;
spin_lock_irqsave(&pm_qos_lock, flags);
list_add(&dep->list,
- &pm_qos_array[pm_qos_class]->requirements.list);
+ &pm_qos_array[pm_qos_class]->requests.list);
spin_unlock_irqrestore(&pm_qos_lock, flags);
update_target(pm_qos_class);
-
- return 0;
}
-cleanup:
- kfree(dep);
- return -ENOMEM;
+ return dep;
}
-EXPORT_SYMBOL_GPL(pm_qos_add_requirement);
+EXPORT_SYMBOL_GPL(pm_qos_add_request);
/**
- * pm_qos_update_requirement - modifies an existing qos request
- * @pm_qos_class: identifies which list of qos request to us
- * @name: identifies the request
+ * pm_qos_update_request - modifies an existing qos request
+ * @pm_qos_req : handle to list element holding a pm_qos request to use
* @value: defines the qos request
*
- * Updates an existing qos requirement for the pm_qos_class of parameters along
+ * Updates an existing qos request for the pm_qos_class of parameters along
* with updating the target pm_qos_class value.
*
- * If the named request isn't in the list then no change is made.
+ * Attempts are made to make this code callable on hot code paths.
*/
-int pm_qos_update_requirement(int pm_qos_class, char *name, s32 new_value)
+void pm_qos_update_request(struct pm_qos_request_list *pm_qos_req,
+ s32 new_value)
{
unsigned long flags;
- struct requirement_list *node;
int pending_update = 0;
+ s32 temp;
+ s32 extreme_value;
spin_lock_irqsave(&pm_qos_lock, flags);
- list_for_each_entry(node,
- &pm_qos_array[pm_qos_class]->requirements.list, list) {
- if (strcmp(node->name, name) == 0) {
- if (new_value == PM_QOS_DEFAULT_VALUE)
- node->value =
- pm_qos_array[pm_qos_class]->default_value;
- else
- node->value = new_value;
- pending_update = 1;
- break;
- }
- }
+ if (new_value == PM_QOS_DEFAULT_VALUE)
+ temp = pm_qos_array[pm_qos_req->pm_qos_class]->default_value;
+ else
+ temp = new_value;
+
+ pm_qos_req->value = temp;
+ if (temp != pm_qos_req->value) {
+ pending_update = 1;
+
spin_unlock_irqrestore(&pm_qos_lock, flags);
if (pending_update)
- update_target(pm_qos_class);
-
- return 0;
+ update_target(pm_qos_req->pm_qos_class);
}
-EXPORT_SYMBOL_GPL(pm_qos_update_requirement);
+EXPORT_SYMBOL_GPL(pm_qos_update_request);
/**
- * pm_qos_remove_requirement - modifies an existing qos request
- * @pm_qos_class: identifies which list of qos request to us
- * @name: identifies the request
+ * pm_qos_remove_request - modifies an existing qos request
+ * @pm_qos_req: handle to request list element
*
- * Will remove named qos request from pm_qos_class list of parameters and
- * recompute the current target value for the pm_qos_class.
+ * Will remove pm qos request from the list of requests and
+ * recompute the current target value for the pm_qos_class. Call this
+ * on slow code paths.
*/
-void pm_qos_remove_requirement(int pm_qos_class, char *name)
+void pm_qos_remove_request(struct pm_qos_request_list *pm_qos_req)
{
unsigned long flags;
- struct requirement_list *node;
+ struct pm_qos_request_list *node;
int pending_update = 0;
+ int qos_class = pm_qos_req->pm_qos_class;
spin_lock_irqsave(&pm_qos_lock, flags);
- list_for_each_entry(node,
- &pm_qos_array[pm_qos_class]->requirements.list, list) {
- if (strcmp(node->name, name) == 0) {
- kfree(node->name);
- list_del(&node->list);
- kfree(node);
- pending_update = 1;
- break;
- }
- }
+ list_del(&pm_qos_req->list);
+ kfree(pm_qos_req);
spin_unlock_irqrestore(&pm_qos_lock, flags);
- if (pending_update)
- update_target(pm_qos_class);
+ update_target(qos_class);
}
-EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
+EXPORT_SYMBOL_GPL(pm_qos_remove_request);
/**
* pm_qos_add_notifier - sets notification entry for changes to target value
@@ -314,7 +299,7 @@ EXPORT_SYMBOL_GPL(pm_qos_remove_requirement);
* will register the notifier into a notification chain that gets called
* upon changes to the pm_qos_class target value.
*/
- int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
+int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
{
int retval;
@@ -344,22 +329,17 @@ int pm_qos_remove_notifier(int pm_qos_class, struct notifier_block *notifier)
}
EXPORT_SYMBOL_GPL(pm_qos_remove_notifier);
-#define PID_NAME_LEN sizeof("process_1234567890")
-static char name[PID_NAME_LEN];
-
static int pm_qos_power_open(struct inode *inode, struct file *filp)
{
- int ret;
long pm_qos_class;
lock_kernel();
pm_qos_class = find_pm_qos_object_by_minor(iminor(inode));
+
if (pm_qos_class >= 0) {
- filp->private_data = (void *)pm_qos_class;
- sprintf(name, "process_%d", current->pid);
- ret = pm_qos_add_requirement(pm_qos_class, name,
- PM_QOS_DEFAULT_VALUE);
- if (ret >= 0) {
+ filp->private_data = (void *) pm_qos_add_request(pm_qos_class,
+ PM_QOS_DEFAULT_VALUE);
+ if (filp->private_data) {
unlock_kernel();
return 0;
}
@@ -371,11 +351,10 @@ static int pm_qos_power_open(struct inode *inode, struct file *filp)
static int pm_qos_power_release(struct inode *inode, struct file *filp)
{
- int pm_qos_class;
+ struct pm_qos_request_list *req;
- pm_qos_class = (long)filp->private_data;
- sprintf(name, "process_%d", current->pid);
- pm_qos_remove_requirement(pm_qos_class, name);
+ req = (struct pm_qos_request_list *)filp->private_data;
+ pm_qos_remove_request(req);
return 0;
}
@@ -384,15 +363,14 @@ static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
size_t count, loff_t *f_pos)
{
s32 value;
- int pm_qos_class;
+ struct pm_qos_request_list *pm_qos_req;
- pm_qos_class = (long)filp->private_data;
if (count != sizeof(s32))
return -EINVAL;
if (copy_from_user(&value, buf, sizeof(s32)))
return -EFAULT;
- sprintf(name, "process_%d", current->pid);
- pm_qos_update_requirement(pm_qos_class, name, value);
+ pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
+ pm_qos_update_request(pm_qos_req, value);
return sizeof(s32);
}
--
1.6.3.3
On Sun 2009-11-29 17:09:53, 640E9920 wrote:
> I'm using this crazy email address because I have problems getting to
> linux.intel.com from home, and my work at intel has changed a bit.
>
> This is the first in a 5 part series that attempts to update PM_QOS to
> use handles instead of named strings in its kernel api. It seams that
> some folks are using pm_qos on hot paths and the overhead of the list
> walks and string compares is a problem.
>
> Most of the changes came from [email protected], and I spent some time
> cleaning up the API.
>
> Also, I couldn't resist myself in renaming the API's a bit give the fact
> that the signatures changed enough that I had to touch all the pm_qos
> users anyway. I changed *requirement* to *request* in keeping with the
> way PM_QOS really only does best effort. I've felt "requirement" is too
> strong a word for the way it works.
Looks good on quick scan. Moving away from strings is certainly good.
> @@ -384,15 +363,14 @@ static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
> size_t count, loff_t *f_pos)
> {
> s32 value;
> - int pm_qos_class;
> + struct pm_qos_request_list *pm_qos_req;
>
> - pm_qos_class = (long)filp->private_data;
> if (count != sizeof(s32))
> return -EINVAL;
> if (copy_from_user(&value, buf, sizeof(s32)))
> return -EFAULT;
> - sprintf(name, "process_%d", current->pid);
> - pm_qos_update_requirement(pm_qos_class, name, value);
> + pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
> + pm_qos_update_request(pm_qos_req, value);
>
> return sizeof(s32);
> }
Umm.. passing binary numbers like that... is not exactly good
interface. Think endianness issues when writing to it from high-level
language.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
On Mon, Jan 04, 2010 at 09:31:27AM +0100, Pavel Machek wrote:
> On Sun 2009-11-29 17:09:53, 640E9920 wrote:
> > I'm using this crazy email address because I have problems getting to
> > linux.intel.com from home, and my work at intel has changed a bit.
> >
> > This is the first in a 5 part series that attempts to update PM_QOS to
> > use handles instead of named strings in its kernel api. It seams that
> > some folks are using pm_qos on hot paths and the overhead of the list
> > walks and string compares is a problem.
> >
> > Most of the changes came from [email protected], and I spent some time
> > cleaning up the API.
> >
> > Also, I couldn't resist myself in renaming the API's a bit give the fact
> > that the signatures changed enough that I had to touch all the pm_qos
> > users anyway. I changed *requirement* to *request* in keeping with the
> > way PM_QOS really only does best effort. I've felt "requirement" is too
> > strong a word for the way it works.
>
> Looks good on quick scan. Moving away from strings is certainly good.
thanks I'll target to get this into linux-next for 2.6.34.
>
> > @@ -384,15 +363,14 @@ static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
> > size_t count, loff_t *f_pos)
> > {
> > s32 value;
> > - int pm_qos_class;
> > + struct pm_qos_request_list *pm_qos_req;
> >
> > - pm_qos_class = (long)filp->private_data;
> > if (count != sizeof(s32))
> > return -EINVAL;
> > if (copy_from_user(&value, buf, sizeof(s32)))
> > return -EFAULT;
> > - sprintf(name, "process_%d", current->pid);
> > - pm_qos_update_requirement(pm_qos_class, name, value);
> > + pm_qos_req = (struct pm_qos_request_list *)filp->private_data;
> > + pm_qos_update_request(pm_qos_req, value);
> >
> > return sizeof(s32);
> > }
>
> Umm.. passing binary numbers like that... is not exactly good
> interface. Think endianness issues when writing to it from high-level
> language.
>
yeah. At the moment I can't recall why I went binary for the ABI,
we can revisit this, but its been in the wild for a few years now :(
I guess I can do some tricks to see if its a hex string representation
of a number and parse that as well as supporting the s32. i.e. accept
strings "0x0000000" ... "0xFFFFFFFF" and return -EINVAL for anything
else.
--mgross
> Pavel
> --
> (english) http://www.livejournal.com/~pavelmachek
> (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
> _______________________________________________
> linux-pm mailing list
> [email protected]
> https://lists.linux-foundation.org/mailman/listinfo/linux-pm
Hi!
> > Umm.. passing binary numbers like that... is not exactly good
> > interface. Think endianness issues when writing to it from high-level
> > language.
>
> yeah. At the moment I can't recall why I went binary for the ABI,
> we can revisit this, but its been in the wild for a few years now :(
>
> I guess I can do some tricks to see if its a hex string representation
> of a number and parse that as well as supporting the s32. i.e. accept
> strings "0x0000000" ... "0xFFFFFFFF" and return -EINVAL for anything
> else.
Maybe you could use length for detection? If they are writing 4 bytes,
it is s32, 10 bytes means ascii?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
On Wed, Jan 06, 2010 at 08:18:31PM +0100, Pavel Machek wrote:
> Hi!
>
> > > Umm.. passing binary numbers like that... is not exactly good
> > > interface. Think endianness issues when writing to it from high-level
> > > language.
> >
> > yeah. At the moment I can't recall why I went binary for the ABI,
> > we can revisit this, but its been in the wild for a few years now :(
> >
> > I guess I can do some tricks to see if its a hex string representation
> > of a number and parse that as well as supporting the s32. i.e. accept
> > strings "0x0000000" ... "0xFFFFFFFF" and return -EINVAL for anything
> > else.
>
> Maybe you could use length for detection? If they are writing 4 bytes,
> it is s32, 10 bytes means ascii?
That is what I was thinking + making sure the chars in the string where
valid hex digits ;) It would be easy to do. Let me know if you think I
should attempt to roll that into the kernel ABI exposed by this thing.
--mgross
On Thu 2010-01-07 12:55:58, mark gross wrote:
> On Wed, Jan 06, 2010 at 08:18:31PM +0100, Pavel Machek wrote:
> > Hi!
> >
> > > > Umm.. passing binary numbers like that... is not exactly good
> > > > interface. Think endianness issues when writing to it from high-level
> > > > language.
> > >
> > > yeah. At the moment I can't recall why I went binary for the ABI,
> > > we can revisit this, but its been in the wild for a few years now :(
> > >
> > > I guess I can do some tricks to see if its a hex string representation
> > > of a number and parse that as well as supporting the s32. i.e. accept
> > > strings "0x0000000" ... "0xFFFFFFFF" and return -EINVAL for anything
> > > else.
> >
> > Maybe you could use length for detection? If they are writing 4 bytes,
> > it is s32, 10 bytes means ascii?
>
> That is what I was thinking + making sure the chars in the string where
> valid hex digits ;) It would be easy to do. Let me know if you think I
> should attempt to roll that into the kernel ABI exposed by this thing.
I think that would be nice, yes.
Pavel
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