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

Matt Helsley
2006-11-03T04:23:01Z

[-- Attachment #1: task-watchers-register-cpusets --]
[-- Type: text/plain, Size: 7836 bytes --]

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;