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authorTom Zanussi <zanussi@kernel.org>2021-09-02 15:57:12 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-09-08 15:29:16 -0400
commitc910db943d35d4ac4b77570ece76e0799af24233 (patch)
tree6d6bcf3cbd73b5e82ad79e25dbe90dd40d56491d /kernel/trace
parent0be083cee42ec78ba6f9148f5b12a00aa2fb8bd3 (diff)
tracing: Dynamically allocate the per-elt hist_elt_data array
Setting the hist_elt_data.field_var_str[] array unconditionally to a size of SYNTH_FIELD_MAX elements wastes space unnecessarily. The actual number of elements needed can be calculated at run-time instead. In most cases, this will save a lot of space since it's a per-elt array which isn't normally close to being full. It also allows us to increase SYNTH_FIELD_MAX without worrying about even more wastage when we do that. Link: https://lkml.kernel.org/r/d52ae0ad5e1b59af7c4f54faf3fc098461fd82b3.camel@kernel.org Signed-off-by: Tom Zanussi <zanussi@kernel.org> Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace_events_hist.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 9d91b1c06957..a6061a69aa84 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -508,7 +508,8 @@ struct track_data {
struct hist_elt_data {
char *comm;
u64 *var_ref_vals;
- char *field_var_str[SYNTH_FIELDS_MAX];
+ char **field_var_str;
+ int n_field_var_str;
};
struct snapshot_context {
@@ -1401,9 +1402,11 @@ static void hist_elt_data_free(struct hist_elt_data *elt_data)
{
unsigned int i;
- for (i = 0; i < SYNTH_FIELDS_MAX; i++)
+ for (i = 0; i < elt_data->n_field_var_str; i++)
kfree(elt_data->field_var_str[i]);
+ kfree(elt_data->field_var_str);
+
kfree(elt_data->comm);
kfree(elt_data);
}
@@ -1451,6 +1454,13 @@ static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt)
size = STR_VAR_LEN_MAX;
+ elt_data->field_var_str = kcalloc(n_str, sizeof(char *), GFP_KERNEL);
+ if (!elt_data->field_var_str) {
+ hist_elt_data_free(elt_data);
+ return -EINVAL;
+ }
+ elt_data->n_field_var_str = n_str;
+
for (i = 0; i < n_str; i++) {
elt_data->field_var_str[i] = kzalloc(size, GFP_KERNEL);
if (!elt_data->field_var_str[i]) {

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