Skip to content

Commit

Permalink
tracing: Remove code which merges duplicates
Browse files Browse the repository at this point in the history 
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: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
  • Loading branch information
@vedangpatel1 @rostedt
vedangpatel1 authored and rostedt committed Mar 10, 2018
1 parent cbf4100 commit c193707
Show file tree
Hide file tree
Showing 3 changed files with 6 additions and 95 deletions.
11 changes: 0 additions & 11 deletions kernel/trace/trace_events_hist.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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,
};
Expand Down
83 changes: 6 additions & 77 deletions kernel/trace/tracing_map.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand All @@ -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)
Expand Down Expand Up @@ -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;
Expand Down
7 changes: 0 additions & 7 deletions kernel/trace/tracing_map.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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.
*
Expand All @@ -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);
Expand Down

0 comments on commit c193707

Please sign in to comment.