[PATCH 4/9] Task Watchers v2: Register cpuset task watcher

[Matt Helsley <matthltc@us.ibm.com>]

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Register a task watcher for cpusets instead of hooking into
copy_process() and do_exit() directly.

Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
---
 include/linux/cpuset.h |    4 ----
 kernel/cpuset.c        |    7 +++++--
 kernel/exit.c          |    2 --
 kernel/fork.c          |    6 +-----
 4 files changed, 6 insertions(+), 13 deletions(-)

Benchmark results:
System: 4 1.7GHz ppc64 (Power 4+) processors, 30968600MB RAM, 2.6.19-rc2-mm2 kernel

Clone	Number of Children Cloned
	5000		7500		10000		12500		15000		17500
	---------------------------------------------------------------------------------------
Mean	18023.8 	18243.8 	18485.1 	18422.9 	18469.4 	18505.1
Dev	317.163 	297.266 	298.965 	288.518 	294.607 	290.491
Err (%)	1.75969 	1.6294 		1.61733 	1.56608 	1.59511 	1.56979

Fork	Number of Children Forked
	5000		7500		10000		12500		15000		17500
	---------------------------------------------------------------------------------------
Mean	17950.9 	18149.7 	18283 		18409.3 	18414.1 	18450.3
Dev	310.206 	300.925 	297.458 	290.673 	298.75	 	301.009
Err (%)	1.72808 	1.65802 	1.62696 	1.57895 	1.6224 		1.63146

Kernbench:
Elapsed: 124.248s User: 439.83s System: 46.258s CPU: 390.7%
439.80user 46.26system 2:04.53elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k
439.79user 46.20system 2:04.29elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k
439.80user 46.42system 2:04.37elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k
439.88user 46.16system 2:04.36elapsed 390%CPU (0avgtext+0avgdata 0maxresident)k
439.76user 46.21system 2:03.72elapsed 392%CPU (0avgtext+0avgdata 0maxresident)k
439.93user 46.21system 2:03.90elapsed 392%CPU (0avgtext+0avgdata 0maxresident)k
439.88user 46.25system 2:04.67elapsed 389%CPU (0avgtext+0avgdata 0maxresident)k
439.79user 46.38system 2:04.31elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k
439.90user 46.25system 2:04.09elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k
439.77user 46.24system 2:04.24elapsed 391%CPU (0avgtext+0avgdata 0maxresident)k

Index: linux-2.6.19-rc2-mm2/kernel/fork.c
===================================================================
--- linux-2.6.19-rc2-mm2.orig/kernel/fork.c
+++ linux-2.6.19-rc2-mm2/kernel/fork.c
@@ -28,11 +28,10 @@
 #include <linux/mman.h>
 #include <linux/fs.h>
 #include <linux/nsproxy.h>
 #include <linux/capability.h>
 #include <linux/cpu.h>
-#include <linux/cpuset.h>
 #include <linux/security.h>
 #include <linux/swap.h>
 #include <linux/syscalls.h>
 #include <linux/jiffies.h>
 #include <linux/futex.h>
@@ -1053,17 +1052,16 @@ static struct task_struct *copy_process(
 		p->tgid = current->tgid;
 
 	retval = notify_task_watchers(WATCH_TASK_INIT, clone_flags, p);
 	if (retval < 0)
 		goto bad_fork_cleanup_delays_binfmt;
-	cpuset_fork(p);
 #ifdef CONFIG_NUMA
  	p->mempolicy = mpol_copy(p->mempolicy);
  	if (IS_ERR(p->mempolicy)) {
  		retval = PTR_ERR(p->mempolicy);
  		p->mempolicy = NULL;
- 		goto bad_fork_cleanup_cpuset;
+ 		goto bad_fork_cleanup_delays_binfmt;
  	}
 	mpol_fix_fork_child_flag(p);
 #endif
 #ifdef CONFIG_TRACE_IRQFLAGS
 	p->irq_events = 0;
@@ -1272,13 +1270,11 @@ bad_fork_cleanup_files:
 bad_fork_cleanup_security:
 	security_task_free(p);
 bad_fork_cleanup_policy:
 #ifdef CONFIG_NUMA
 	mpol_free(p->mempolicy);
-bad_fork_cleanup_cpuset:
 #endif
-	cpuset_exit(p);
 bad_fork_cleanup_delays_binfmt:
 	delayacct_tsk_free(p);
 	notify_task_watchers(WATCH_TASK_FREE, 0, p);
 	if (p->binfmt)
 		module_put(p->binfmt->module);
Index: linux-2.6.19-rc2-mm2/kernel/cpuset.c
===================================================================
--- linux-2.6.19-rc2-mm2.orig/kernel/cpuset.c
+++ linux-2.6.19-rc2-mm2/kernel/cpuset.c
@@ -47,10 +47,11 @@
 #include <linux/stat.h>
 #include <linux/string.h>
 #include <linux/time.h>
 #include <linux/backing-dev.h>
 #include <linux/sort.h>
+#include <linux/task_watchers.h>
 
 #include <asm/uaccess.h>
 #include <asm/atomic.h>
 #include <linux/mutex.h>
 
@@ -2172,17 +2173,18 @@ void __init cpuset_init_smp(void)
  *
  * At the point that cpuset_fork() is called, 'current' is the parent
  * task, and the passed argument 'child' points to the child task.
  **/
 
-void cpuset_fork(struct task_struct *child)
+static void cpuset_fork(unsigned long clone_flags, struct task_struct *child)
 {
 	task_lock(current);
 	child->cpuset = current->cpuset;
 	atomic_inc(&child->cpuset->count);
 	task_unlock(current);
 }
+task_watcher_func(init, cpuset_fork);
 
 /**
  * cpuset_exit - detach cpuset from exiting task
  * @tsk: pointer to task_struct of exiting process
  *
@@ -2239,11 +2241,11 @@ void cpuset_fork(struct task_struct *chi
  *    to NULL here, and check in cpuset_update_task_memory_state()
  *    for a NULL pointer.  This hack avoids that NULL check, for no
  *    cost (other than this way too long comment ;).
  **/
 
-void cpuset_exit(struct task_struct *tsk)
+static void cpuset_exit(unsigned long exit_code, struct task_struct *tsk)
 {
 	struct cpuset *cs;
 
 	cs = tsk->cpuset;
 	tsk->cpuset = &top_cpuset;	/* the_top_cpuset_hack - see above */
@@ -2258,10 +2260,11 @@ void cpuset_exit(struct task_struct *tsk
 		cpuset_release_agent(pathbuf);
 	} else {
 		atomic_dec(&cs->count);
 	}
 }
+task_watcher_func(free, cpuset_exit);
 
 /**
  * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
  * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
  *
Index: linux-2.6.19-rc2-mm2/kernel/exit.c
===================================================================
--- linux-2.6.19-rc2-mm2.orig/kernel/exit.c
+++ linux-2.6.19-rc2-mm2/kernel/exit.c
@@ -28,11 +28,10 @@
 #include <linux/mount.h>
 #include <linux/proc_fs.h>
 #include <linux/mempolicy.h>
 #include <linux/taskstats_kern.h>
 #include <linux/delayacct.h>
-#include <linux/cpuset.h>
 #include <linux/syscalls.h>
 #include <linux/signal.h>
 #include <linux/posix-timers.h>
 #include <linux/cn_proc.h>
 #include <linux/mutex.h>
@@ -920,11 +919,10 @@ fastcall NORET_TYPE void do_exit(long co
 	if (group_dead)
 		acct_process();
 	__exit_files(tsk);
 	__exit_fs(tsk);
 	exit_thread();
-	cpuset_exit(tsk);
 	exit_keys(tsk);
 
 	if (group_dead && tsk->signal->leader)
 		disassociate_ctty(1);
 
Index: linux-2.6.19-rc2-mm2/include/linux/cpuset.h
===================================================================
--- linux-2.6.19-rc2-mm2.orig/include/linux/cpuset.h
+++ linux-2.6.19-rc2-mm2/include/linux/cpuset.h
@@ -17,12 +17,10 @@
 extern int number_of_cpusets;	/* How many cpusets are defined in system? */
 
 extern int cpuset_init_early(void);
 extern int cpuset_init(void);
 extern void cpuset_init_smp(void);
-extern void cpuset_fork(struct task_struct *p);
-extern void cpuset_exit(struct task_struct *p);
 extern cpumask_t cpuset_cpus_allowed(struct task_struct *p);
 extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
 #define cpuset_current_mems_allowed (current->mems_allowed)
 void cpuset_init_current_mems_allowed(void);
 void cpuset_update_task_memory_state(void);
@@ -69,12 +67,10 @@ extern void cpuset_track_online_nodes(vo
 #else /* !CONFIG_CPUSETS */
 
 static inline int cpuset_init_early(void) { return 0; }
 static inline int cpuset_init(void) { return 0; }
 static inline void cpuset_init_smp(void) {}
-static inline void cpuset_fork(struct task_struct *p) {}
-static inline void cpuset_exit(struct task_struct *p) {}
 
 static inline cpumask_t cpuset_cpus_allowed(struct task_struct *p)
 {
 	return cpu_possible_map;
 }

--

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