[PATCH 0/3] Implement triggers for control groups.

[PATCH 0/3] Implement triggers for control groups.

[Pavel Emelyanov]

Hi, guys.

This is the final set I'm going to send to Andrew. It has a new
feature - fail counter reset - and splitted, so I send it for a
final review (maybe some Acked-by-s ;) ) before sending to Andrew.

Signed-off-by: Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>

[PATCH 1/3] Add the trigger callback to struct cftype

[Pavel Emelyanov]

Trigger callback can be used to receive a kick-up from the
user space. The string written is ignored.

The cftype->private is used for multiplexing events.

Signed-off-by: Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>

---
 include/linux/cgroup.h |    8 ++++++++
 kernel/cgroup.c        |    4 ++++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 785a01c..2d1d151 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -243,6 +243,14 @@ struct cftype {
 	 */
 	int (*write_s64) (struct cgroup *cgrp, struct cftype *cft, s64 val);
 
+	/*
+	 * trigger() callback can be used to get some kick from the
+	 * userspace, when the actual string written is not important
+	 * at all. The private field can be used to determine the
+	 * kick type for multiplexing.
+	 */
+	int (*trigger)(struct cgroup *cgrp, unsigned int event);
+
 	int (*release) (struct inode *inode, struct file *file);
 };
 
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index e8e8ec4..f2d8f25 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1410,6 +1410,10 @@ static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
 		return cft->write(cgrp, cft, file, buf, nbytes, ppos);
 	if (cft->write_u64 || cft->write_s64)
 		return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos);
+	if (cft->trigger) {
+		int ret = cft->trigger(cgrp, (unsigned int)cft->private);
+		return ret ? ret : nbytes;
+	}
 	return -EINVAL;
 }
 
-- 
1.5.3.4

Re: [PATCH 1/3] Add the trigger callback to struct cftype

[Paul Menage]

On Thu, Mar 13, 2008 at 4:36 AM, Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org> wrote:
> Trigger callback can be used to receive a kick-up from the
>  user space. The string written is ignored.
>
>  The cftype->private is used for multiplexing events.
>
>  Signed-off-by: Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>

Acked-by: Paul Menage <menage-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>

I'm not sure about the behaviour of passing cft->private rather than
just cft, but we can always change that later if it turns that some
user needs the cft pointer for some other reason.

Paul

>
>  ---
>   include/linux/cgroup.h |    8 ++++++++
>   kernel/cgroup.c        |    4 ++++
>   2 files changed, 12 insertions(+), 0 deletions(-)
>
>  diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
>  index 785a01c..2d1d151 100644
>  --- a/include/linux/cgroup.h
>  +++ b/include/linux/cgroup.h
>  @@ -243,6 +243,14 @@ struct cftype {
>          */
>         int (*write_s64) (struct cgroup *cgrp, struct cftype *cft, s64 val);
>
>  +       /*
>  +        * trigger() callback can be used to get some kick from the
>  +        * userspace, when the actual string written is not important
>  +        * at all. The private field can be used to determine the
>  +        * kick type for multiplexing.
>  +        */
>  +       int (*trigger)(struct cgroup *cgrp, unsigned int event);
>  +
>         int (*release) (struct inode *inode, struct file *file);
>   };
>
>  diff --git a/kernel/cgroup.c b/kernel/cgroup.c
>  index e8e8ec4..f2d8f25 100644
>  --- a/kernel/cgroup.c
>  +++ b/kernel/cgroup.c
>  @@ -1410,6 +1410,10 @@ static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
>                 return cft->write(cgrp, cft, file, buf, nbytes, ppos);
>         if (cft->write_u64 || cft->write_s64)
>                 return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos);
>  +       if (cft->trigger) {
>  +               int ret = cft->trigger(cgrp, (unsigned int)cft->private);
>  +               return ret ? ret : nbytes;
>  +       }
>         return -EINVAL;
>   }
>
>  --
>  1.5.3.4
>
>

[PATCH 2/3] Use triggers in force_empty and max_usage files

[Pavel Emelyanov]

Signed-off-by: Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>

---
 mm/memcontrol.c |   21 ++++++---------------
 1 files changed, 6 insertions(+), 15 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c27141d..d3ec3e3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -868,27 +868,18 @@ static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
 				mem_cgroup_write_strategy);
 }
 
-static ssize_t mem_cgroup_max_reset(struct cgroup *cont, struct cftype *cft,
-				struct file *file, const char __user *userbuf,
-				size_t nbytes, loff_t *ppos)
+static int mem_cgroup_max_reset(struct cgroup *cont, unsigned int event)
 {
 	struct mem_cgroup *mem;
 
 	mem = mem_cgroup_from_cont(cont);
 	res_counter_reset_max(&mem->res);
-	return nbytes;
+	return 0;
 }
 
-static ssize_t mem_force_empty_write(struct cgroup *cont,
-				struct cftype *cft, struct file *file,
-				const char __user *userbuf,
-				size_t nbytes, loff_t *ppos)
+static int mem_force_empty_write(struct cgroup *cont, unsigned int event)
 {
-	struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
-	int ret = mem_cgroup_force_empty(mem);
-	if (!ret)
-		ret = nbytes;
-	return ret;
+	return mem_cgroup_force_empty(mem_cgroup_from_cont(cont));
 }
 
 static const struct mem_cgroup_stat_desc {
@@ -936,7 +927,7 @@ static struct cftype mem_cgroup_files[] = {
 	{
 		.name = "max_usage_in_bytes",
 		.private = RES_MAX_USAGE,
-		.write = mem_cgroup_max_reset,
+		.trigger = mem_cgroup_max_reset,
 		.read_u64 = mem_cgroup_read,
 	},
 	{
@@ -952,7 +943,7 @@ static struct cftype mem_cgroup_files[] = {
 	},
 	{
 		.name = "force_empty",
-		.write = mem_force_empty_write,
+		.trigger = mem_force_empty_write,
 	},
 	{
 		.name = "stat",
-- 
1.5.3.4

[PATCH 3/3] Implement failcounter reset

[Pavel Emelyanov]

Merge two resets into one mem_cgroup_reset() function to
demonstrate how multiplexing work.

Besides, I have plans to move the files, that correspond to
res_counter to the res_counter.c file and somehow "import" 
them into controller. I don't know how to make it gracefully
yet, but merging resets of max_usage and failcnt in one function 
will be there for sure.

Signed-off-by: Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>

---
 include/linux/res_counter.h |    8 ++++++++
 mm/memcontrol.c             |   14 +++++++++++---
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index df8085a..3c05d6d 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -141,4 +141,12 @@ static inline void res_counter_reset_max(struct res_counter *cnt)
 	spin_unlock_irqrestore(&cnt->lock, flags);
 }
 
+static inline void res_counter_reset_failcnt(struct res_counter *cnt)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cnt->lock, flags);
+	cnt->failcnt = 0;
+	spin_unlock_irqrestore(&cnt->lock, flags);
+}
 #endif
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d3ec3e3..5852b23 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -868,12 +868,19 @@ static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
 				mem_cgroup_write_strategy);
 }
 
-static int mem_cgroup_max_reset(struct cgroup *cont, unsigned int event)
+static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
 {
 	struct mem_cgroup *mem;
 
 	mem = mem_cgroup_from_cont(cont);
-	res_counter_reset_max(&mem->res);
+	switch (event) {
+		case RES_MAX_USAGE:
+			res_counter_reset_max(&mem->res);
+			break;
+		case RES_FAILCNT:
+			res_counter_reset_failcnt(&mem->res);
+			break;
+	}
 	return 0;
 }
 
@@ -927,7 +934,7 @@ static struct cftype mem_cgroup_files[] = {
 	{
 		.name = "max_usage_in_bytes",
 		.private = RES_MAX_USAGE,
-		.trigger = mem_cgroup_max_reset,
+		.trigger = mem_cgroup_reset,
 		.read_u64 = mem_cgroup_read,
 	},
 	{
@@ -939,6 +946,7 @@ static struct cftype mem_cgroup_files[] = {
 	{
 		.name = "failcnt",
 		.private = RES_FAILCNT,
+		.trigger = mem_cgroup_reset,
 		.read_u64 = mem_cgroup_read,
 	},
 	{
-- 
1.5.3.4

Re: [PATCH 0/3] Implement triggers for control groups.

[KAMEZAWA Hiroyuki]

On Thu, 13 Mar 2008 14:34:39 +0300
Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org> wrote:

> Hi, guys.
> 
> This is the final set I'm going to send to Andrew. It has a new
> feature - fail counter reset - and splitted, so I send it for a
> final review (maybe some Acked-by-s ;) ) before sending to Andrew.
> 
> Signed-off-by: Pavel Emelyanov <xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>

I like this new interface. thank you.

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu-+CUm20s59erQFUHtdCDX3A@public.gmane.org>