[PATCH] perf: remove include of cgroup.h from perf_event.h

[PATCH] perf: remove include of cgroup.h from perf_event.h

[Li Zefan]

Move struct perf_cgroup_info and perf_cgroup to kernel/perf/core.c,
and then we can remove include of cgroup.h.

Signed-off-by: Li Zefan <lizefan@huawei.com>
---
 include/linux/perf_event.h | 18 +-----------------
 kernel/events/core.c       | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index e47ee46..8737e1c 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -21,7 +21,6 @@
  */
 
 #ifdef CONFIG_PERF_EVENTS
-# include <linux/cgroup.h>
 # include <asm/perf_event.h>
 # include <asm/local64.h>
 #endif
@@ -299,22 +298,7 @@ struct swevent_hlist {
 #define PERF_ATTACH_GROUP	0x02
 #define PERF_ATTACH_TASK	0x04
 
-#ifdef CONFIG_CGROUP_PERF
-/*
- * perf_cgroup_info keeps track of time_enabled for a cgroup.
- * This is a per-cpu dynamically allocated data structure.
- */
-struct perf_cgroup_info {
-	u64				time;
-	u64				timestamp;
-};
-
-struct perf_cgroup {
-	struct				cgroup_subsys_state css;
-	struct				perf_cgroup_info *info;	/* timing info, one per cpu */
-};
-#endif
-
+struct perf_cgroup;
 struct ring_buffer;
 
 /**
diff --git a/kernel/events/core.c b/kernel/events/core.c
index b0cd865..5976a2a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -37,6 +37,7 @@
 #include <linux/ftrace_event.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/mm_types.h>
+#include <linux/cgroup.h>
 
 #include "internal.h"
 
@@ -234,6 +235,20 @@ static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
 #ifdef CONFIG_CGROUP_PERF
 
 /*
+ * perf_cgroup_info keeps track of time_enabled for a cgroup.
+ * This is a per-cpu dynamically allocated data structure.
+ */
+struct perf_cgroup_info {
+	u64				time;
+	u64				timestamp;
+};
+
+struct perf_cgroup {
+	struct cgroup_subsys_state	css;
+	struct perf_cgroup_info		*info;
+};
+
+/*
  * Must ensure cgroup is pinned (css_get) before calling
  * this function. In other words, we cannot call this function
  * if there is no cgroup event for the current CPU context.
-- 
1.8.0.2

Re: [PATCH] perf: remove include of cgroup.h from perf_event.h

[Stephane Eranian]

On Tue, Mar 5, 2013 at 4:38 AM, Li Zefan <lizefan@huawei.com> wrote:
> Move struct perf_cgroup_info and perf_cgroup to kernel/perf/core.c,
> and then we can remove include of cgroup.h.
>
> Signed-off-by: Li Zefan <lizefan@huawei.com>
> ---
>  include/linux/perf_event.h | 18 +-----------------
>  kernel/events/core.c       | 15 +++++++++++++++
>  2 files changed, 16 insertions(+), 17 deletions(-)
>
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index e47ee46..8737e1c 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -21,7 +21,6 @@
>   */
>
>  #ifdef CONFIG_PERF_EVENTS
> -# include <linux/cgroup.h>
>  # include <asm/perf_event.h>
>  # include <asm/local64.h>
>  #endif
> @@ -299,22 +298,7 @@ struct swevent_hlist {
>  #define PERF_ATTACH_GROUP      0x02
>  #define PERF_ATTACH_TASK       0x04
>
> -#ifdef CONFIG_CGROUP_PERF
> -/*
> - * perf_cgroup_info keeps track of time_enabled for a cgroup.
> - * This is a per-cpu dynamically allocated data structure.
> - */
> -struct perf_cgroup_info {
> -       u64                             time;
> -       u64                             timestamp;
> -};
> -
> -struct perf_cgroup {
> -       struct                          cgroup_subsys_state css;
> -       struct                          perf_cgroup_info *info; /* timing info, one per cpu */
> -};
> -#endif
> -
> +struct perf_cgroup;

The problem is that you have struct perf_cgroup in the struct perf_event
structure. Today, this field is not referenced outside of kernel/events/core.c
But it is available outside this file. If someday the field is reference, your
changes will have to do reverted. So I am wondering what is the point
of the change right now?


>  struct ring_buffer;
>
>  /**
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index b0cd865..5976a2a 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -37,6 +37,7 @@
>  #include <linux/ftrace_event.h>
>  #include <linux/hw_breakpoint.h>
>  #include <linux/mm_types.h>
> +#include <linux/cgroup.h>
>
>  #include "internal.h"
>
> @@ -234,6 +235,20 @@ static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
>  #ifdef CONFIG_CGROUP_PERF
>
>  /*
> + * perf_cgroup_info keeps track of time_enabled for a cgroup.
> + * This is a per-cpu dynamically allocated data structure.
> + */
> +struct perf_cgroup_info {
> +       u64                             time;
> +       u64                             timestamp;
> +};
> +
> +struct perf_cgroup {
> +       struct cgroup_subsys_state      css;
> +       struct perf_cgroup_info         *info;
> +};
> +
> +/*
>   * Must ensure cgroup is pinned (css_get) before calling
>   * this function. In other words, we cannot call this function
>   * if there is no cgroup event for the current CPU context.
> --
> 1.8.0.2
>

Re: [PATCH] perf: remove include of cgroup.h from perf_event.h

[Li Zefan]

On 2013/3/5 16:33, Stephane Eranian wrote:
> On Tue, Mar 5, 2013 at 4:38 AM, Li Zefan <lizefan@huawei.com> wrote:
>> Move struct perf_cgroup_info and perf_cgroup to kernel/perf/core.c,
>> and then we can remove include of cgroup.h.
>>
>> Signed-off-by: Li Zefan <lizefan@huawei.com>
>> ---
>>  include/linux/perf_event.h | 18 +-----------------
>>  kernel/events/core.c       | 15 +++++++++++++++
>>  2 files changed, 16 insertions(+), 17 deletions(-)
>>
>> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
>> index e47ee46..8737e1c 100644
>> --- a/include/linux/perf_event.h
>> +++ b/include/linux/perf_event.h
>> @@ -21,7 +21,6 @@
>>   */
>>
>>  #ifdef CONFIG_PERF_EVENTS
>> -# include <linux/cgroup.h>
>>  # include <asm/perf_event.h>
>>  # include <asm/local64.h>
>>  #endif
>> @@ -299,22 +298,7 @@ struct swevent_hlist {
>>  #define PERF_ATTACH_GROUP      0x02
>>  #define PERF_ATTACH_TASK       0x04
>>
>> -#ifdef CONFIG_CGROUP_PERF
>> -/*
>> - * perf_cgroup_info keeps track of time_enabled for a cgroup.
>> - * This is a per-cpu dynamically allocated data structure.
>> - */
>> -struct perf_cgroup_info {
>> -       u64                             time;
>> -       u64                             timestamp;
>> -};
>> -
>> -struct perf_cgroup {
>> -       struct                          cgroup_subsys_state css;
>> -       struct                          perf_cgroup_info *info; /* timing info, one per cpu */
>> -};
>> -#endif
>> -
>> +struct perf_cgroup;
> 
> The problem is that you have struct perf_cgroup in the struct perf_event
> structure. Today, this field is not referenced outside of kernel/events/core.c
> But it is available outside this file. If someday the field is reference, your
> changes will have to do reverted. So I am wondering what is the point
> of the change right now?
> 

I touch cgroup.h quite frequently, so I'd like to reduce the compile time caused
by cgroup.h changes, so I've made a few patches to remove cgroup.h from some
header files.

It's better to expose as less interfaces as possible, and if someone wants to
export someting he should think about if it's the right thing to do.

Like we often make static functions usable to external users, and also often do the
reverse thing, this patch is nothing special.

Re: [PATCH] perf: remove include of cgroup.h from perf_event.h

[Tejun Heo]

(cc'ing Steven and Frederic and quoting whole body)

Hello, guys.

On Tue, Mar 05, 2013 at 06:37:12PM +0800, Li Zefan wrote:
> On 2013/3/5 16:33, Stephane Eranian wrote:
> > On Tue, Mar 5, 2013 at 4:38 AM, Li Zefan <lizefan@huawei.com> wrote:
> >> Move struct perf_cgroup_info and perf_cgroup to kernel/perf/core.c,
> >> and then we can remove include of cgroup.h.
> >>
> >> Signed-off-by: Li Zefan <lizefan@huawei.com>
> >> ---
> >>  include/linux/perf_event.h | 18 +-----------------
> >>  kernel/events/core.c       | 15 +++++++++++++++
> >>  2 files changed, 16 insertions(+), 17 deletions(-)
> >>
> >> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> >> index e47ee46..8737e1c 100644
> >> --- a/include/linux/perf_event.h
> >> +++ b/include/linux/perf_event.h
> >> @@ -21,7 +21,6 @@
> >>   */
> >>
> >>  #ifdef CONFIG_PERF_EVENTS
> >> -# include <linux/cgroup.h>
> >>  # include <asm/perf_event.h>
> >>  # include <asm/local64.h>
> >>  #endif
> >> @@ -299,22 +298,7 @@ struct swevent_hlist {
> >>  #define PERF_ATTACH_GROUP      0x02
> >>  #define PERF_ATTACH_TASK       0x04
> >>
> >> -#ifdef CONFIG_CGROUP_PERF
> >> -/*
> >> - * perf_cgroup_info keeps track of time_enabled for a cgroup.
> >> - * This is a per-cpu dynamically allocated data structure.
> >> - */
> >> -struct perf_cgroup_info {
> >> -       u64                             time;
> >> -       u64                             timestamp;
> >> -};
> >> -
> >> -struct perf_cgroup {
> >> -       struct                          cgroup_subsys_state css;
> >> -       struct                          perf_cgroup_info *info; /* timing info, one per cpu */
> >> -};
> >> -#endif
> >> -
> >> +struct perf_cgroup;
> > 
> > The problem is that you have struct perf_cgroup in the struct perf_event
> > structure. Today, this field is not referenced outside of kernel/events/core.c
> > But it is available outside this file. If someday the field is reference, your
> > changes will have to do reverted. So I am wondering what is the point
> > of the change right now?
> > 
> 
> I touch cgroup.h quite frequently, so I'd like to reduce the compile time caused
> by cgroup.h changes, so I've made a few patches to remove cgroup.h from some
> header files.
> 
> It's better to expose as less interfaces as possible, and if someone wants to
> export someting he should think about if it's the right thing to do.
> 
> Like we often make static functions usable to external users, and also often do the
> reverse thing, this patch is nothing special.

I don't care either way.  Steven, Frederic, Ingo?

Thanks.

-- 
tejun

Re: [PATCH] perf: remove include of cgroup.h from perf_event.h

[Ingo Molnar]

* Stephane Eranian <eranian@google.com> wrote:

> > - * This is a per-cpu dynamically allocated data structure.
> > - */
> > -struct perf_cgroup_info {
> > -       u64                             time;
> > -       u64                             timestamp;
> > -};
> > -
> > -struct perf_cgroup {
> > -       struct                          cgroup_subsys_state css;
> > -       struct                          perf_cgroup_info *info; /* timing info, one per cpu */
> > -};
> > -#endif
> > -
> > +struct perf_cgroup;
> 
> The problem is that you have struct perf_cgroup in the struct perf_event 
> structure. Today, this field is not referenced outside of kernel/events/core.c But 
> it is available outside this file. If someday the field is reference, your changes 
> will have to do reverted. So I am wondering what is the point of the change right 
> now?

It's standard practice to not define the type for task_struct or other kernel 
subsystems.

For example slab caches can be created via kmem_cache_create() anywhere in the tree, 
but the internal structure is only known to the SLAB subsystem.

Thanks,

	Ingo

Re: [PATCH] perf: remove include of cgroup.h from perf_event.h

[Stephane Eranian]

On Wed, Mar 6, 2013 at 11:31 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Stephane Eranian <eranian@google.com> wrote:
>
>> > - * This is a per-cpu dynamically allocated data structure.
>> > - */
>> > -struct perf_cgroup_info {
>> > -       u64                             time;
>> > -       u64                             timestamp;
>> > -};
>> > -
>> > -struct perf_cgroup {
>> > -       struct                          cgroup_subsys_state css;
>> > -       struct                          perf_cgroup_info *info; /* timing info, one per cpu */
>> > -};
>> > -#endif
>> > -
>> > +struct perf_cgroup;
>>
>> The problem is that you have struct perf_cgroup in the struct perf_event
>> structure. Today, this field is not referenced outside of kernel/events/core.c But
>> it is available outside this file. If someday the field is reference, your changes
>> will have to do reverted. So I am wondering what is the point of the change right
>> now?
>
> It's standard practice to not define the type for task_struct or other kernel
> subsystems.
>
> For example slab caches can be created via kmem_cache_create() anywhere in the tree,
> but the internal structure is only known to the SLAB subsystem.
>
I am fine with the change.

[tip:perf/core] perf: Remove include of cgroup.h from perf_event.h

[tip-bot for Li Zefan]

Commit-ID:  877c685607925238e302cd3aa38788dca6c1b226
Gitweb:     http://git.kernel.org/tip/877c685607925238e302cd3aa38788dca6c1b226
Author:     Li Zefan <lizefan@huawei.com>
AuthorDate: Tue, 5 Mar 2013 11:38:08 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 6 Mar 2013 11:32:56 +0100

perf: Remove include of cgroup.h from perf_event.h

Move struct perf_cgroup_info and perf_cgroup to
kernel/perf/core.c, and then we can remove include of cgroup.h.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/513568A0.6020804@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 include/linux/perf_event.h | 18 +-----------------
 kernel/events/core.c       | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 17 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index e47ee46..8737e1c 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -21,7 +21,6 @@
  */
 
 #ifdef CONFIG_PERF_EVENTS
-# include <linux/cgroup.h>
 # include <asm/perf_event.h>
 # include <asm/local64.h>
 #endif
@@ -299,22 +298,7 @@ struct swevent_hlist {
 #define PERF_ATTACH_GROUP	0x02
 #define PERF_ATTACH_TASK	0x04
 
-#ifdef CONFIG_CGROUP_PERF
-/*
- * perf_cgroup_info keeps track of time_enabled for a cgroup.
- * This is a per-cpu dynamically allocated data structure.
- */
-struct perf_cgroup_info {
-	u64				time;
-	u64				timestamp;
-};
-
-struct perf_cgroup {
-	struct				cgroup_subsys_state css;
-	struct				perf_cgroup_info *info;	/* timing info, one per cpu */
-};
-#endif
-
+struct perf_cgroup;
 struct ring_buffer;
 
 /**
diff --git a/kernel/events/core.c b/kernel/events/core.c
index b0cd865..5976a2a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -37,6 +37,7 @@
 #include <linux/ftrace_event.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/mm_types.h>
+#include <linux/cgroup.h>
 
 #include "internal.h"
 
@@ -234,6 +235,20 @@ static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
 #ifdef CONFIG_CGROUP_PERF
 
 /*
+ * perf_cgroup_info keeps track of time_enabled for a cgroup.
+ * This is a per-cpu dynamically allocated data structure.
+ */
+struct perf_cgroup_info {
+	u64				time;
+	u64				timestamp;
+};
+
+struct perf_cgroup {
+	struct cgroup_subsys_state	css;
+	struct perf_cgroup_info		*info;
+};
+
+/*
  * Must ensure cgroup is pinned (css_get) before calling
  * this function. In other words, we cannot call this function
  * if there is no cgroup event for the current CPU context.