Commit c193707d authored by Vedang Patel's avatar Vedang Patel Committed by Steven Rostedt (VMware)
Browse files

tracing: Remove code which merges duplicates 

We now have the logic to detect and remove duplicates in the
tracing_map hash table. The code which merges duplicates in the
histogram is redundant now. So, modify this code just to detect
duplicates. The duplication detection code is still kept to ensure
that any rare race condition which might cause duplicates does not go
unnoticed.

Link: http://lkml.kernel.org/r/55215cf59e2674391bdaf772fdafc4c393352b03.1516069914.git.tom.zanussi@linux.intel.com



Signed-off-by: default avatarVedang Patel <vedang.patel@intel.com>
Signed-off-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent cbf4100e

kernel/trace/trace_events_hist.c

+0 −11
Original line number Diff line number Diff line
@@ -340,16 +340,6 @@ static int hist_trigger_elt_comm_alloc(struct tracing_map_elt *elt) 
	return 0;

}



static void hist_trigger_elt_comm_copy(struct tracing_map_elt *to,

				       struct tracing_map_elt *from)

{

	char *comm_from = from->private_data;

	char *comm_to = to->private_data;



	if (comm_from)

		memcpy(comm_to, comm_from, TASK_COMM_LEN + 1);

}



static void hist_trigger_elt_comm_init(struct tracing_map_elt *elt)

{

	char *comm = elt->private_data;
@@ -360,7 +350,6 @@ static void hist_trigger_elt_comm_init(struct tracing_map_elt *elt) 


static const struct tracing_map_ops hist_trigger_elt_comm_ops = {

	.elt_alloc	= hist_trigger_elt_comm_alloc,

	.elt_copy	= hist_trigger_elt_comm_copy,

	.elt_free	= hist_trigger_elt_comm_free,

	.elt_init	= hist_trigger_elt_comm_init,

};

kernel/trace/tracing_map.c

+6 −77
Original line number Diff line number Diff line
@@ -847,67 +847,15 @@ create_sort_entry(void *key, struct tracing_map_elt *elt) 
	return sort_entry;

}



static struct tracing_map_elt *copy_elt(struct tracing_map_elt *elt)

{

	struct tracing_map_elt *dup_elt;

	unsigned int i;



	dup_elt = tracing_map_elt_alloc(elt->map);

	if (IS_ERR(dup_elt))

		return NULL;



	if (elt->map->ops && elt->map->ops->elt_copy)

		elt->map->ops->elt_copy(dup_elt, elt);



	dup_elt->private_data = elt->private_data;

	memcpy(dup_elt->key, elt->key, elt->map->key_size);



	for (i = 0; i < elt->map->n_fields; i++) {

		atomic64_set(&dup_elt->fields[i].sum,

			     atomic64_read(&elt->fields[i].sum));

		dup_elt->fields[i].cmp_fn = elt->fields[i].cmp_fn;

	}



	return dup_elt;

}



static int merge_dup(struct tracing_map_sort_entry **sort_entries,

		     unsigned int target, unsigned int dup)

{

	struct tracing_map_elt *target_elt, *elt;

	bool first_dup = (target - dup) == 1;

	int i;



	if (first_dup) {

		elt = sort_entries[target]->elt;

		target_elt = copy_elt(elt);

		if (!target_elt)

			return -ENOMEM;

		sort_entries[target]->elt = target_elt;

		sort_entries[target]->elt_copied = true;

	} else

		target_elt = sort_entries[target]->elt;



	elt = sort_entries[dup]->elt;



	for (i = 0; i < elt->map->n_fields; i++)

		atomic64_add(atomic64_read(&elt->fields[i].sum),

			     &target_elt->fields[i].sum);



	sort_entries[dup]->dup = true;



	return 0;

}



static int merge_dups(struct tracing_map_sort_entry **sort_entries,

static void detect_dups(struct tracing_map_sort_entry **sort_entries,

		      int n_entries, unsigned int key_size)

{

	unsigned int dups = 0, total_dups = 0;

	int err, i, j;

	int i;

	void *key;



	if (n_entries < 2)

		return total_dups;

		return;



	sort(sort_entries, n_entries, sizeof(struct tracing_map_sort_entry *),

	     (int (*)(const void *, const void *))cmp_entries_dup, NULL);
@@ -916,30 +864,14 @@ static int merge_dups(struct tracing_map_sort_entry **sort_entries, 
	for (i = 1; i < n_entries; i++) {

		if (!memcmp(sort_entries[i]->key, key, key_size)) {

			dups++; total_dups++;

			err = merge_dup(sort_entries, i - dups, i);

			if (err)

				return err;

			continue;

		}

		key = sort_entries[i]->key;

		dups = 0;

	}



	if (!total_dups)

		return total_dups;



	for (i = 0, j = 0; i < n_entries; i++) {

		if (!sort_entries[i]->dup) {

			sort_entries[j] = sort_entries[i];

			if (j++ != i)

				sort_entries[i] = NULL;

		} else {

			destroy_sort_entry(sort_entries[i]);

			sort_entries[i] = NULL;

		}

	}



	return total_dups;

	WARN_ONCE(total_dups > 0,

		  "Duplicates detected: %d\n", total_dups);

}



static bool is_key(struct tracing_map *map, unsigned int field_idx)
@@ -1065,10 +997,7 @@ int tracing_map_sort_entries(struct tracing_map *map, 
		return 1;

	}



	ret = merge_dups(entries, n_entries, map->key_size);

	if (ret < 0)

		goto free;

	n_entries -= ret;

	detect_dups(entries, n_entries, map->key_size);



	if (is_key(map, sort_keys[0].field_idx))

		cmp_entries_fn = cmp_entries_key;

kernel/trace/tracing_map.h

+0 −7
Original line number Diff line number Diff line
@@ -215,11 +215,6 @@ struct tracing_map { 
 *	Element allocation occurs before tracing begins, when the

 *	tracing_map_init() call is made by client code.

 *

 * @elt_copy: At certain points in the lifetime of an element, it may

 *	need to be copied.  The copy should include a copy of the

 *	client-allocated data, which can be copied into the 'to'

 *	element from the 'from' element.

 *

 * @elt_free: When a tracing_map_elt is freed, this function is called

 *	and allows client-allocated per-element data to be freed.

 *
@@ -233,8 +228,6 @@ struct tracing_map { 
 */

struct tracing_map_ops {

	int			(*elt_alloc)(struct tracing_map_elt *elt);

	void			(*elt_copy)(struct tracing_map_elt *to,

					    struct tracing_map_elt *from);

	void			(*elt_free)(struct tracing_map_elt *elt);

	void			(*elt_clear)(struct tracing_map_elt *elt);

	void			(*elt_init)(struct tracing_map_elt *elt);

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