Message-ID: <20071116022240.GC16953@Krystal>
Date:	Thu, 15 Nov 2007 21:22:40 -0500
From:	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To:	Mike Mason <mmlnx@...ibm.com>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC 4/7] LTTng instrumentation kernel

* Mike Mason (mmlnx@...ibm.com) wrote:
> This patch uses _trace_mark in lockdep.c and printk.c.  I assume they 
> should be trace_mark (no '_' prefix).
>

Since it folows the markers with immediate values patch, it requires to
use the underscored version, because the lockdep code can be called from
the return from trap (thus breakpoint) because of the interrupt enable
instrumentation and therefore cause a recursive trap.

The underscored version means "don't use the optimized version".

Mathieu


> Mike Mason
>
>
> Mathieu Desnoyers wrote:
>
> Core kernel events.
>
> *not* present in this patch because they are architecture specific :
> - syscall entry/exit
> - traps
> - kernel thread creation
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
> ---
> include/linux/module.h |    1 +
> kernel/exit.c          |    5 +++++
> kernel/fork.c          |    4 ++++
> kernel/irq/handle.c    |    6 ++++++
> kernel/itimer.c        |   11 +++++++++++
> kernel/kthread.c       |    4 ++++
> kernel/lockdep.c       |   19 +++++++++++++++++++
> kernel/module.c        |   25 +++++++++++++++++++++++++
> kernel/printk.c        |   26 ++++++++++++++++++++++++++
> kernel/sched.c         |   11 +++++++++++
> kernel/signal.c        |    2 ++
> kernel/softirq.c       |   22 ++++++++++++++++++++++
> kernel/timer.c         |   12 +++++++++++-
> 13 files changed, 147 insertions(+), 1 deletion(-)
>
> Index: linux-2.6-lttng/kernel/irq/handle.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/irq/handle.c	2007-11-13 09:25:27.000000000 
> -0500
> +++ linux-2.6-lttng/kernel/irq/handle.c	2007-11-13 09:49:33.000000000 -0500
> @@ -130,6 +130,10 @@ irqreturn_t handle_IRQ_event(unsigned in
> {
> 	irqreturn_t ret, retval = IRQ_NONE;
> 	unsigned int status = 0;
> +	struct pt_regs *regs = get_irq_regs();
> +
> +	trace_mark(kernel_irq_entry, "irq_id %u kernel_mode %u", irq,
> +		(regs)?(!user_mode(regs)):(1));
>
> 	handle_dynamic_tick(action);
>
> @@ -148,6 +152,8 @@ irqreturn_t handle_IRQ_event(unsigned in
> 		add_interrupt_randomness(irq);
> 	local_irq_disable();
>
> +	trace_mark(kernel_irq_exit, MARK_NOARGS);
> +
> 	return retval;
> }
>
> Index: linux-2.6-lttng/kernel/itimer.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/itimer.c	2007-11-13 09:25:27.000000000 
> -0500
> +++ linux-2.6-lttng/kernel/itimer.c	2007-11-13 09:49:33.000000000 -0500
> @@ -132,6 +132,8 @@ enum hrtimer_restart it_real_fn(struct h
> 	struct signal_struct *sig =
> 		container_of(timer, struct signal_struct, real_timer);
>
> +	trace_mark(kernel_timer_itimer_expired, "pid %d", sig->tsk->pid);
> +
> 	send_group_sig_info(SIGALRM, SEND_SIG_PRIV, sig->tsk);
>
> 	return HRTIMER_NORESTART;
> @@ -157,6 +159,15 @@ int do_setitimer(int which, struct itime
> 	    !timeval_valid(&value->it_interval))
> 		return -EINVAL;
>
> +	trace_mark(kernel_timer_itimer_set,
> +			"which %d interval_sec %ld interval_usec %ld "
> +			"value_sec %ld value_usec %ld",
> +			which,
> +			value->it_interval.tv_sec,
> +			value->it_interval.tv_usec,
> +			value->it_value.tv_sec,
> +			value->it_value.tv_usec);
> +
> 	switch (which) {
> 	case ITIMER_REAL:
> again:
> Index: linux-2.6-lttng/kernel/kthread.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/kthread.c	2007-11-13 09:25:27.000000000 
> -0500
> +++ linux-2.6-lttng/kernel/kthread.c	2007-11-13 09:49:33.000000000 -0500
> @@ -195,6 +195,8 @@ int kthread_stop(struct task_struct *k)
> 	/* It could exit after stop_info.k set, but before wake_up_process. */
> 	get_task_struct(k);
>
> +	trace_mark(kernel_kthread_stop, "pid %d", k->pid);
> +
> 	/* Must init completion *before* thread sees kthread_stop_info.k */
> 	init_completion(&kthread_stop_info.done);
> 	smp_wmb();
> @@ -210,6 +212,8 @@ int kthread_stop(struct task_struct *k)
> 	ret = kthread_stop_info.err;
> 	mutex_unlock(&kthread_stop_lock);
>
> +	trace_mark(kernel_kthread_stop_ret, "ret %d", ret);
> +
> 	return ret;
> }
> EXPORT_SYMBOL(kthread_stop);
> Index: linux-2.6-lttng/kernel/lockdep.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/lockdep.c	2007-11-13 09:25:27.000000000 
> -0500
> +++ linux-2.6-lttng/kernel/lockdep.c	2007-11-13 09:49:33.000000000 -0500
> @@ -2014,6 +2014,9 @@ void trace_hardirqs_on(void)
> 	struct task_struct *curr = current;
> 	unsigned long ip;
>
> +	_trace_mark(locking_hardirqs_on, "ip #p%lu",
> +		(unsigned long) __builtin_return_address(0));
> +
> 	if (unlikely(!debug_locks || current->lockdep_recursion))
> 		return;
>
> @@ -2061,6 +2064,9 @@ void trace_hardirqs_off(void)
> {
> 	struct task_struct *curr = current;
>
> +	_trace_mark(locking_hardirqs_off, "ip #p%lu",
> +		(unsigned long) __builtin_return_address(0));
> +
> 	if (unlikely(!debug_locks || current->lockdep_recursion))
> 		return;
>
> @@ -2088,6 +2094,9 @@ void trace_softirqs_on(unsigned long ip)
> {
> 	struct task_struct *curr = current;
>
> +	_trace_mark(locking_softirqs_on, "ip #p%lu",
> +		(unsigned long) __builtin_return_address(0));
> +
> 	if (unlikely(!debug_locks))
> 		return;
>
> @@ -2122,6 +2131,9 @@ void trace_softirqs_off(unsigned long ip
> {
> 	struct task_struct *curr = current;
>
> +	_trace_mark(locking_softirqs_off, "ip #p%lu",
> +		(unsigned long) __builtin_return_address(0));
> +
> 	if (unlikely(!debug_locks))
> 		return;
>
> @@ -2358,6 +2370,10 @@ static int __lock_acquire(struct lockdep
> 	int chain_head = 0;
> 	u64 chain_key;
>
> +	_trace_mark(locking_lock_acquire,
> +		"ip #p%lu subclass %u lock %p trylock %d",
> +		ip, subclass, lock, trylock);
> +
> 	if (!prove_locking)
> 		check = 1;
>
> @@ -2631,6 +2647,9 @@ __lock_release(struct lockdep_map *lock,
> {
> 	struct task_struct *curr = current;
>
> +	_trace_mark(locking_lock_release, "ip #p%lu lock %p nested %d",
> +		ip, lock, nested);
> +
> 	if (!check_unlock(curr, lock, ip))
> 		return;
>
> Index: linux-2.6-lttng/kernel/printk.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/printk.c	2007-11-13 09:25:27.000000000 
> -0500
> +++ linux-2.6-lttng/kernel/printk.c	2007-11-13 09:49:33.000000000 -0500
> @@ -619,6 +619,7 @@ asmlinkage int printk(const char *fmt, .
> 	int r;
>
> 	va_start(args, fmt);
> +	trace_mark(kernel_printk, "ip %p", __builtin_return_address(0));
> 	r = vprintk(fmt, args);
> 	va_end(args);
>
> @@ -653,6 +654,31 @@ asmlinkage int vprintk(const char *fmt, 	/* Emit the 
> output into the temporary buffer */
> 	printed_len = vscnprintf(printk_buf, sizeof(printk_buf), fmt, args);
>
> +	if (printed_len > 0) {
> +		unsigned int loglevel;
> +		int mark_len;
> +		char *mark_buf;
> +		char saved_char;
> +
> +		if (printk_buf[0] == '<' && printk_buf[1] >= '0' &&
> +		   printk_buf[1] <= '7' && printk_buf[2] == '>') {
> +			loglevel = printk_buf[1] - '0';
> +			mark_buf = &printk_buf[3];
> +			mark_len = printed_len - 3;
> +		} else {
> +			loglevel = default_message_loglevel;
> +			mark_buf = printk_buf;
> +			mark_len = printed_len;
> +		}
> +		if (mark_buf[mark_len - 1] == '\n')
> +			mark_len--;
> +		saved_char = mark_buf[mark_len];
> +		mark_buf[mark_len] = '\0';
> +		_trace_mark(kernel_vprintk, "loglevel %c string %s ip %p",
> +			loglevel, mark_buf, __builtin_return_address(0));
> +		mark_buf[mark_len] = saved_char;
> +	}
> +
> 	/*
> 	 * Copy the output into log_buf.  If the caller didn't provide
> 	 * appropriate log level tags, we insert them here
> Index: linux-2.6-lttng/kernel/sched.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/sched.c	2007-11-13 09:25:27.000000000 -0500
> +++ linux-2.6-lttng/kernel/sched.c	2007-11-13 09:49:33.000000000 -0500
> @@ -1161,6 +1161,8 @@ void wait_task_inactive(struct task_stru
> 		 * just go back and repeat.
> 		 */
> 		rq = task_rq_lock(p, &flags);
> +		trace_mark(kernel_sched_wait_task, "pid %d state %ld",
> +			p->pid, p->state);
> 		running = task_running(rq, p);
> 		on_rq = p->se.on_rq;
> 		task_rq_unlock(rq, &flags);
> @@ -1495,6 +1497,8 @@ static int try_to_wake_up(struct task_st
> #endif
>
> 	rq = task_rq_lock(p, &flags);
> +	trace_mark(kernel_sched_try_wakeup, "pid %d state %ld",
> +		p->pid, p->state);
> 	old_state = p->state;
> 	if (!(old_state & state))
> 		goto out;
> @@ -1733,6 +1737,8 @@ void fastcall wake_up_new_task(struct ta
> 	struct rq *rq;
>
> 	rq = task_rq_lock(p, &flags);
> +	trace_mark(kernel_sched_wakeup_new_task, "pid %d state %ld",
> +		p->pid, p->state);
> 	BUG_ON(p->state != TASK_RUNNING);
> 	update_rq_clock(rq);
>
> @@ -1911,6 +1917,9 @@ context_switch(struct rq *rq, struct tas
> 	struct mm_struct *mm, *oldmm;
>
> 	prepare_task_switch(rq, prev, next);
> +	trace_mark(kernel_sched_schedule,
> +		"prev_pid %d next_pid %d prev_state %ld",
> +		prev->pid, next->pid, prev->state);
> 	mm = next->mm;
> 	oldmm = prev->active_mm;
> 	/*
> @@ -2139,6 +2148,8 @@ static void sched_migrate_task(struct ta
> 	    || unlikely(cpu_is_offline(dest_cpu)))
> 		goto out;
>
> +	trace_mark(kernel_sched_migrate_task, "pid %d state %ld dest_cpu %d",
> +		p->pid, p->state, dest_cpu);
> 	/* force the process onto the specified CPU */
> 	if (migrate_task(p, dest_cpu, &req)) {
> 		/* Need to wait for migration thread (might exit: take ref). */
> Index: linux-2.6-lttng/kernel/signal.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/signal.c	2007-11-13 09:25:27.000000000 
> -0500
> +++ linux-2.6-lttng/kernel/signal.c	2007-11-13 09:49:33.000000000 -0500
> @@ -663,6 +663,8 @@ static int send_signal(int sig, struct s
> 	struct sigqueue * q = NULL;
> 	int ret = 0;
>
> +	trace_mark(kernel_send_signal, "pid %d signal %d", t->pid, sig);
> +
> 	/*
> 	 * Deliver the signal to listening signalfds. This must be called
> 	 * with the sighand lock held.
> Index: linux-2.6-lttng/kernel/softirq.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/softirq.c	2007-11-13 09:25:27.000000000 
> -0500
> +++ linux-2.6-lttng/kernel/softirq.c	2007-11-13 09:49:33.000000000 -0500
> @@ -229,7 +229,15 @@ restart:
>
> 	do {
> 		if (pending & 1) {
> +			trace_mark(kernel_softirq_entry, "softirq_id %lu",
> +				((unsigned long)h
> +					- (unsigned long)softirq_vec)
> +					/ sizeof(*h));
> 			h->action(h);
> +			trace_mark(kernel_softirq_exit, "softirq_id %lu",
> +				((unsigned long)h
> +					- (unsigned long)softirq_vec)
> +					/ sizeof(*h));
> 			rcu_bh_qsctr_inc(cpu);
> 		}
> 		h++;
> @@ -315,6 +323,8 @@ void irq_exit(void)
>  */
> inline fastcall void raise_softirq_irqoff(unsigned int nr)
> {
> +	trace_mark(kernel_softirq_raise, "softirq %u", nr);
> +
> 	__raise_softirq_irqoff(nr);
>
> 	/*
> @@ -400,7 +410,13 @@ static void tasklet_action(struct softir
> 			if (!atomic_read(&t->count)) {
> 				if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
> 					BUG();
> +				trace_mark(kernel_tasklet_low_entry,
> +						"func %p data %lu",
> +						t->func, t->data);
> 				t->func(t->data);
> +				trace_mark(kernel_tasklet_low_exit,
> +						"func %p data %lu",
> +						t->func, t->data);
> 				tasklet_unlock(t);
> 				continue;
> 			}
> @@ -433,7 +449,13 @@ static void tasklet_hi_action(struct sof
> 			if (!atomic_read(&t->count)) {
> 				if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
> 					BUG();
> +				trace_mark(kernel_tasklet_high_entry,
> +						"func %p data %lu",
> +						t->func, t->data);
> 				t->func(t->data);
> +				trace_mark(kernel_tasklet_high_exit,
> +						"func %p data %lu",
> +						t->func, t->data);
> 				tasklet_unlock(t);
> 				continue;
> 			}
> Index: linux-2.6-lttng/kernel/timer.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/timer.c	2007-11-13 09:25:27.000000000 -0500
> +++ linux-2.6-lttng/kernel/timer.c	2007-11-13 09:49:33.000000000 -0500
> @@ -43,6 +43,7 @@
> #include <asm/div64.h>
> #include <asm/timex.h>
> #include <asm/io.h>
> +#include <asm/irq_regs.h>
>
> u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
>
> @@ -290,6 +291,8 @@ static void internal_add_timer(tvec_base
> 		i = (expires >> (TVR_BITS + 3 * TVN_BITS)) & TVN_MASK;
> 		vec = base->tv5.vec + i;
> 	}
> +	trace_mark(kernel_timer_set, "expires %lu function %p data %lu",
> +		expires, timer->function, timer->data);
> 	/*
> 	 * Timers are FIFO:
> 	 */
> @@ -931,6 +934,11 @@ void do_timer(unsigned long ticks)
> {
> 	jiffies_64 += ticks;
> 	update_times(ticks);
> +	trace_mark(kernel_timer_update_time,
> +		"jiffies #8u%llu xtime_sec %ld xtime_nsec %ld "
> +		"walltomonotonic_sec %ld walltomonotonic_nsec %ld",
> +		jiffies_64, xtime.tv_sec, xtime.tv_nsec,
> +		wall_to_monotonic.tv_sec, wall_to_monotonic.tv_nsec);
> }
>
> #ifdef __ARCH_WANT_SYS_ALARM
> @@ -1012,7 +1020,9 @@ asmlinkage long sys_getegid(void)
>
> static void process_timeout(unsigned long __data)
> {
> -	wake_up_process((struct task_struct *)__data);
> +	struct task_struct *task = (struct task_struct *)__data;
> +	trace_mark(kernel_timer_timeout, "pid %d", task->pid);
> +	wake_up_process(task);
> }
>
> /**
> Index: linux-2.6-lttng/kernel/exit.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/exit.c	2007-11-13 09:25:27.000000000 -0500
> +++ linux-2.6-lttng/kernel/exit.c	2007-11-13 09:49:33.000000000 -0500
> @@ -177,6 +177,7 @@ repeat:
>
> 	write_unlock_irq(&tasklist_lock);
> 	release_thread(p);
> +	trace_mark(kernel_process_free, "pid %d", p->pid);
> 	call_rcu(&p->rcu, delayed_put_task_struct);
>
> 	p = leader;
> @@ -994,6 +995,8 @@ fastcall NORET_TYPE void do_exit(long co
>
> 	if (group_dead)
> 		acct_process();
> +	trace_mark(kernel_process_exit, "pid %d", tsk->pid);
> +
> 	exit_sem(tsk);
> 	__exit_files(tsk);
> 	__exit_fs(tsk);
> @@ -1539,6 +1542,8 @@ static long do_wait(pid_t pid, int optio
> 	int flag, retval;
> 	int allowed, denied;
>
> +	trace_mark(kernel_process_wait, "pid %d", pid);
> +
> 	add_wait_queue(&current->signal->wait_chldexit,&wait);
> repeat:
> 	/*
> Index: linux-2.6-lttng/kernel/fork.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/fork.c	2007-11-13 09:25:27.000000000 -0500
> +++ linux-2.6-lttng/kernel/fork.c	2007-11-13 09:49:33.000000000 -0500
> @@ -1435,6 +1435,10 @@ long do_fork(unsigned long clone_flags,
> 	if (!IS_ERR(p)) {
> 		struct completion vfork;
>
> +		trace_mark(kernel_process_fork,
> +			"parent_pid %d child_pid %d child_tgid %d",
> +			current->pid, p->pid, p->tgid);
> +
> 		/*
> 		 * this is enough to call pid_nr_ns here, but this if
> 		 * improves optimisation of regular fork()
> Index: linux-2.6-lttng/include/linux/module.h
> ===================================================================
> --- linux-2.6-lttng.orig/include/linux/module.h	2007-11-13 
> 09:48:41.000000000 -0500
> +++ linux-2.6-lttng/include/linux/module.h	2007-11-13 09:49:33.000000000 
> -0500
> @@ -466,6 +466,7 @@ int register_module_notifier(struct noti
> int unregister_module_notifier(struct notifier_block * nb);
>
> extern void print_modules(void);
> +extern void list_modules(void *call_data);
>
> extern void module_update_markers(void);
>
> Index: linux-2.6-lttng/kernel/module.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/module.c	2007-11-13 09:49:16.000000000 
> -0500
> +++ linux-2.6-lttng/kernel/module.c	2007-11-13 09:49:33.000000000 -0500
> @@ -1294,6 +1294,8 @@ static int __unlink_module(void *_mod)
> /* Free a module, remove from lists, etc (must hold module_mutex). */
> static void free_module(struct module *mod)
> {
> +	trace_mark(kernel_module_free, "name %s", mod->name);
> +
> 	/* Delete from various lists */
> 	stop_machine_run(__unlink_module, mod, NR_CPUS);
> 	remove_notes_attrs(mod);
> @@ -2063,6 +2065,8 @@ static struct module *load_module(void _
> 	/* Get rid of temporary copy */
> 	vfree(hdr);
>
> +	trace_mark(kernel_module_load, "name %s", mod->name);
> +
> 	/* Done! */
> 	return mod;
>
> @@ -2426,6 +2430,27 @@ const struct seq_operations modules_op =
> 	.show	= m_show
> };
>
> +void list_modules(void *call_data)
> +{
> +	/* Enumerate loaded modules */
> +	struct list_head	*i;
> +	struct module		*mod;
> +	unsigned long refcount = 0;
> +
> +	mutex_lock(&module_mutex);
> +	list_for_each(i, &modules) {
> +		mod = list_entry(i, struct module, list);
> +#ifdef CONFIG_MODULE_UNLOAD
> +		refcount = local_read(&mod->ref[0].count);
> +#endif
> +		__trace_mark(0, list_module, call_data,
> +				"name %s state %d refcount %lu",
> +				mod->name, mod->state, refcount);
> +	}
> +	mutex_unlock(&module_mutex);
> +}
> +EXPORT_SYMBOL_GPL(list_modules);
> +
> /* Given an address, look for it in the module exception tables. */
> const struct exception_table_entry *search_module_extables(unsigned long 
> addr)
> {
>
> -- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole 
> Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F 
> BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line 
> "unsubscribe linux-kernel" in the body of a message to 
> majordomo@...r.kernel.org More majordomo info at 
> http://vger.kernel.org/majordomo-info.html Please read the FAQ at 
> http://www.tux.org/lkml/ 

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
-
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