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 <[email protected]>

---
 include/linux/perf_event.h | 18 +-----------------
 kernel/events/core.c       | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 17 deletions(-)

include/linux/perf_event.h +0 -8

index e47ee46..8737e1c 100644
@@ -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;

include/linux/perf_event.h +0 -0

 struct ring_buffer;
 
 /**

kernel/events/core.c +15 -1

index b0cd865..5976a2a 100644
@@ -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

Quoted 40 lines · 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 <[email protected]>

---
 include/linux/perf_event.h | 18 +-----------------
 kernel/events/core.c       | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 17 deletions(-)

include/linux/perf_event.h +0 -16

index e47ee46..8737e1c 100644
@@ -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

include/linux/perf_event.h struct swevent_hlist { · line 301

Quoted 2 lines

include/linux/perf_event.h +1 -1

-
+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?

Quoted 41 lines · Stephane Eranian

Quoted 40 lines · 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 <[email protected]>

---
 include/linux/perf_event.h | 18 +-----------------
 kernel/events/core.c       | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 17 deletions(-)

include/linux/perf_event.h +0 -16

index e47ee46..8737e1c 100644
@@ -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

Quoted 9 lines

include/linux/perf_event.h struct swevent_hlist { · line 301

Quoted 2 lines

include/linux/perf_event.h +1 -1

-
+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.

Quoted 12 lines

- * This is a per-cpu dynamically allocated data structure.
- */

include/linux/perf_event.h +0 -10

-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

Review

Quoted 2 lines

(quoted diff) +1 -1

-
+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?

Quoted 12 lines · Stephane Eranian

Quoted 12 lines

- * This is a per-cpu dynamically allocated data structure.
- */

include/linux/perf_event.h +0 -10

-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

Quoted 8 lines

Review

Quoted 2 lines

(quoted diff) +1 -1

-
+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.