[PATCH 07/11] Task watchers: Register per-task delay accounting task watcher

Matt Helsley
2006-06-14T00:03:05Z

Adapts delayacct to use Task Watchers. Does not adapt taskstats to use Task
Watchers.

Signed-off-by: Matt Helsley <matthltc@us.ibm.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Chandra S. Seetharaman <sekharan@us.ibm.com>
--

include/linux/delayacct.h | 2 +-
kernel/delayacct.c | 23 +++++++++++++++++++++++
kernel/exit.c | 2 --
kernel/fork.c | 2 --
4 files changed, 24 insertions(+), 5 deletions(-)

Index: linux-2.6.17-rc5-mm2/kernel/exit.c
===================================================================
--- linux-2.6.17-rc5-mm2.orig/kernel/exit.c
+++ linux-2.6.17-rc5-mm2/kernel/exit.c
@@ -26,11 +26,10 @@
#include <linux/profile.h>
#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/mutex.h>
@@ -916,11 +915,10 @@ fastcall NORET_TYPE void do_exit(long co
compat_exit_robust_list(tsk);
#endif
tsk->exit_code = code;
taskstats_exit_send(tsk, tidstats, tgidstats);
taskstats_exit_free(tidstats, tgidstats);
- delayacct_tsk_exit(tsk);
notify_result = notify_watchers(WATCH_TASK_FREE, tsk);
WARN_ON(notify_result & NOTIFY_STOP_MASK);

exit_mm(tsk);

Index: linux-2.6.17-rc5-mm2/kernel/fork.c
===================================================================
--- linux-2.6.17-rc5-mm2.orig/kernel/fork.c
+++ linux-2.6.17-rc5-mm2/kernel/fork.c
@@ -41,11 +41,10 @@
#include <linux/ptrace.h>
#include <linux/mount.h>
#include <linux/profile.h>
#include <linux/rmap.h>
#include <linux/acct.h>
-#include <linux/delayacct.h>
#include <linux/notifier.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
@@ -1002,11 +1001,10 @@ static task_t *copy_process(unsigned lon

if (p->binfmt && !try_module_get(p->binfmt->module))
goto bad_fork_cleanup_put_domain;

p->did_exec = 0;
- delayacct_tsk_init(p); /* Must remain after dup_task_struct() */
copy_flags(clone_flags, p);
p->pid = pid;
retval = -EFAULT;
if (clone_flags & CLONE_PARENT_SETTID)
if (put_user(p->pid, parent_tidptr))
Index: linux-2.6.17-rc5-mm2/kernel/delayacct.c
===================================================================
--- linux-2.6.17-rc5-mm2.orig/kernel/delayacct.c
+++ linux-2.6.17-rc5-mm2/kernel/delayacct.c
@@ -16,10 +16,11 @@
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <linux/sysctl.h>
#include <linux/delayacct.h>
+#include <linux/notifier.h>

int delayacct_on __read_mostly; /* Delay accounting turned on/off */
kmem_cache_t *delayacct_cache;

static int __init delayacct_setup_enable(char *str)
@@ -27,17 +28,39 @@ static int __init delayacct_setup_enable
delayacct_on = 1;
return 1;
}
__setup("delayacct", delayacct_setup_enable);

+static int delayacct_watch_task(struct notifier_block *nb, unsigned long val,
+ void *t)
+{
+ struct task_struct *tsk = t;
+ switch(get_watch_event(val)) {
+ case WATCH_TASK_CLONE:
+ delayacct_tsk_init(tsk);
+ break;
+ case WATCH_TASK_FREE:
+ delayacct_tsk_exit(tsk);
+ break;
+ default:
+ return NOTIFY_DONE;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __read_mostly delayacct_nb = {
+ .notifier_call = delayacct_watch_task,
+};
+
void delayacct_init(void)
{
delayacct_cache = kmem_cache_create("delayacct_cache",
sizeof(struct task_delay_info),
0,
SLAB_PANIC,
NULL, NULL);
+ register_task_watcher(&delayacct_nb);
delayacct_tsk_init(&init_task);
}

void __delayacct_tsk_init(struct task_struct *tsk)
{
Index: linux-2.6.17-rc5-mm2/include/linux/delayacct.h
===================================================================
--- linux-2.6.17-rc5-mm2.orig/include/linux/delayacct.h
+++ linux-2.6.17-rc5-mm2/include/linux/delayacct.h
@@ -59,11 +59,11 @@ static inline void delayacct_tsk_init(st
__delayacct_tsk_init(tsk);
}

static inline void delayacct_tsk_exit(struct task_struct *tsk)
{
- if (tsk->delays)
+ if (unlikely(tsk->delays))
__delayacct_tsk_exit(tsk);
}

static inline void delayacct_blkio_start(void)
{

--