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tracing: Remove code which merges duplicates

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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>
This commit is contained in:
Vedang Patel
2018-01-15 20:51:38 -06:00
committed by Steven Rostedt (VMware)
parent cbf4100efb
commit c193707dde
3 changed files with 6 additions and 95 deletions
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83
kernel/trace/tracing_map.c
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@@ -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;