Commit 35fe6d76 authored by Shaohua Li's avatar Shaohua Li Committed by Jens Axboe
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block: use standard blktrace API to output cgroup info for debug notes 



Currently cfq/bfq/blk-throttle output cgroup info in trace in their own
way. Now we have standard blktrace API for this, so convert them to use
it.

Note, this changes the behavior a little bit. cgroup info isn't output
by default, we only do this with 'blk_cgroup' option enabled. cgroup
info isn't output as a string by default too, we only do this with
'blk_cgname' option enabled. Also cgroup info is output in different
position of the note string. I think these behavior changes aren't a big
issue (actually we make trace data shorter which is good), since the
blktrace note is solely for debugging.

Signed-off-by: default avatarShaohua Li <shli@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 69fd5c39

block/bfq-iosched.h

+8 −5
Original line number Diff line number Diff line
@@ -917,13 +917,16 @@ void bfq_add_bfqq_busy(struct bfq_data *bfqd, struct bfq_queue *bfqq); 
struct bfq_group *bfqq_group(struct bfq_queue *bfqq);



#define bfq_log_bfqq(bfqd, bfqq, fmt, args...)	do {			\

	blk_add_trace_msg((bfqd)->queue, "bfq%d%c %s " fmt, (bfqq)->pid,\

			bfq_bfqq_sync((bfqq)) ? 'S' : 'A',		\

			bfqq_group(bfqq)->blkg_path, ##args);		\

	blk_add_cgroup_trace_msg((bfqd)->queue,				\

			bfqg_to_blkg(bfqq_group(bfqq))->blkcg,		\

			"bfq%d%c " fmt, (bfqq)->pid,			\

			bfq_bfqq_sync((bfqq)) ? 'S' : 'A', ##args);	\

} while (0)



#define bfq_log_bfqg(bfqd, bfqg, fmt, args...)	\

	blk_add_trace_msg((bfqd)->queue, "%s " fmt, (bfqg)->blkg_path, ##args)

#define bfq_log_bfqg(bfqd, bfqg, fmt, args...)	do {			\

	blk_add_cgroup_trace_msg((bfqd)->queue,				\

		bfqg_to_blkg(bfqg)->blkcg, fmt, ##args);		\

} while (0)



#else /* CONFIG_BFQ_GROUP_IOSCHED */

block/blk-throttle.c

+2 −4
Original line number Diff line number Diff line
@@ -373,10 +373,8 @@ static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw) 
	if (likely(!blk_trace_note_message_enabled(__td->queue)))	\

		break;							\

	if ((__tg)) {							\

		char __pbuf[128];					\

									\

		blkg_path(tg_to_blkg(__tg), __pbuf, sizeof(__pbuf));	\

		blk_add_trace_msg(__td->queue, "throtl %s " fmt, __pbuf, ##args); \

		blk_add_cgroup_trace_msg(__td->queue,			\

			tg_to_blkg(__tg)->blkcg, "throtl " fmt, ##args);\

	} else {							\

		blk_add_trace_msg(__td->queue, "throtl " fmt, ##args);	\

	}								\

block/cfq-iosched.c

+6 −9
Original line number Diff line number Diff line
@@ -656,20 +656,17 @@ static inline void cfqg_put(struct cfq_group *cfqg) 
}



#define cfq_log_cfqq(cfqd, cfqq, fmt, args...)	do {			\

	char __pbuf[128];						\

									\

	blkg_path(cfqg_to_blkg((cfqq)->cfqg), __pbuf, sizeof(__pbuf));	\

	blk_add_trace_msg((cfqd)->queue, "cfq%d%c%c %s " fmt, (cfqq)->pid, \

	blk_add_cgroup_trace_msg((cfqd)->queue,				\

			cfqg_to_blkg((cfqq)->cfqg)->blkcg,		\

			"cfq%d%c%c " fmt, (cfqq)->pid,			\

			cfq_cfqq_sync((cfqq)) ? 'S' : 'A',		\

			cfqq_type((cfqq)) == SYNC_NOIDLE_WORKLOAD ? 'N' : ' ',\

			  __pbuf, ##args);				\

			  ##args);					\

} while (0)



#define cfq_log_cfqg(cfqd, cfqg, fmt, args...)	do {			\

	char __pbuf[128];						\

									\

	blkg_path(cfqg_to_blkg(cfqg), __pbuf, sizeof(__pbuf));		\

	blk_add_trace_msg((cfqd)->queue, "%s " fmt, __pbuf, ##args);	\

	blk_add_cgroup_trace_msg((cfqd)->queue,				\

			cfqg_to_blkg(cfqg)->blkcg, fmt, ##args);	\

} while (0)



static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,

include/linux/blktrace_api.h

+9 −4
Original line number Diff line number Diff line
@@ -28,10 +28,12 @@ struct blk_trace { 
	atomic_t dropped;

};



struct blkcg;



extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);

extern void blk_trace_shutdown(struct request_queue *);

extern __printf(2, 3)

void __trace_note_message(struct blk_trace *, const char *fmt, ...);

extern __printf(3, 4)

void __trace_note_message(struct blk_trace *, struct blkcg *blkcg, const char *fmt, ...);



/**

 * blk_add_trace_msg - Add a (simple) message to the blktrace stream
@@ -46,12 +48,14 @@ void __trace_note_message(struct blk_trace *, const char *fmt, ...); 
 *     NOTE: Can not use 'static inline' due to presence of var args...

 *

 **/

#define blk_add_trace_msg(q, fmt, ...)					\

#define blk_add_cgroup_trace_msg(q, cg, fmt, ...)			\

	do {								\

		struct blk_trace *bt = (q)->blk_trace;			\

		if (unlikely(bt))					\

			__trace_note_message(bt, fmt, ##__VA_ARGS__);	\

			__trace_note_message(bt, cg, fmt, ##__VA_ARGS__);\

	} while (0)

#define blk_add_trace_msg(q, fmt, ...)					\

	blk_add_cgroup_trace_msg(q, NULL, fmt, ##__VA_ARGS__)

#define BLK_TN_MAX_MSG		128



static inline bool blk_trace_note_message_enabled(struct request_queue *q)
@@ -82,6 +86,7 @@ extern struct attribute_group blk_trace_attr_group; 
# define blk_trace_startstop(q, start)			(-ENOTTY)

# define blk_trace_remove(q)				(-ENOTTY)

# define blk_add_trace_msg(q, fmt, ...)			do { } while (0)

# define blk_add_cgroup_trace_msg(q, cg, fmt, ...)	do { } while (0)

# define blk_trace_remove_sysfs(dev)			do { } while (0)

# define blk_trace_note_message_enabled(q)		(false)

static inline int blk_trace_init_sysfs(struct device *dev)

kernel/trace/blktrace.c

+10 −2
Original line number Diff line number Diff line
@@ -154,7 +154,8 @@ static void trace_note_time(struct blk_trace *bt) 
	local_irq_restore(flags);

}



void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)

void __trace_note_message(struct blk_trace *bt, struct blkcg *blkcg,

	const char *fmt, ...)

{

	int n;

	va_list args;
@@ -178,7 +179,14 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 
	n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);

	va_end(args);



	if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))

		blkcg = NULL;

#ifdef CONFIG_BLK_CGROUP

	trace_note(bt, 0, BLK_TN_MESSAGE, buf, n,

		blkcg ? cgroup_get_kernfs_id(blkcg->css.cgroup) : NULL);

#else

	trace_note(bt, 0, BLK_TN_MESSAGE, buf, n, NULL);

#endif

	local_irq_restore(flags);

}

EXPORT_SYMBOL_GPL(__trace_note_message);
@@ -375,7 +383,7 @@ static ssize_t blk_msg_write(struct file *filp, const char __user *buffer, 
		return PTR_ERR(msg);



	bt = filp->private_data;

	__trace_note_message(bt, "%s", msg);

	__trace_note_message(bt, NULL, "%s", msg);

	kfree(msg);



	return count;

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