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tracing/filter: Call synchronize_sched() just once for system filters 

By separating out the reseting of the filter->n_preds to zero from
the reallocation of preds for the filter, we can reset groups of
filters first, call synchronize_sched() just once, and then reallocate
each of the filters in the system group.

Cc: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2011-01-27 22:46:46 -05:00 committed by Steven Rostedt
parent c9c53ca03d
commit 0fc3ca9a10
1 changed files with 63 additions and 17 deletions
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80
kernel/trace/trace_events_filter.c
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@ -570,17 +570,28 @@ static void __free_preds(struct event_filter *filter)
filter->n_preds = 0;
}
static void reset_preds(struct event_filter *filter)
{
struct filter_pred *pred;
int n_preds = filter->n_preds;
int i;
filter->n_preds = 0;
if (!filter->preds)
return;
for (i = 0; i < n_preds; i++) {
pred = filter->preds[i];
pred->fn = filter_pred_none;
}
}
static void filter_disable_preds(struct ftrace_event_call *call)
{
struct event_filter *filter = call->filter;
int i;
call->flags &= ~TRACE_EVENT_FL_FILTERED;
if (filter->preds) {
for (i = 0; i < filter->n_preds; i++)
filter->preds[i]->fn = filter_pred_none;
}
filter->n_preds = 0;
reset_preds(filter);
}
static void __free_filter(struct event_filter *filter)
@ -620,15 +631,17 @@ static int __alloc_preds(struct event_filter *filter, int n_preds)
if (filter->preds) {
if (filter->a_preds < n_preds) {
/* We need to reallocate */
filter->n_preds = 0;
/*
* It is possible that the filter is currently
* being used. We need to zero out the number
* of preds, wait on preemption and then free
* the preds.
* We need to reallocate.
* We should have already have zeroed out
* the pred count and called synchronized_sched()
* to make sure no one is using the preds.
*/
synchronize_sched();
if (WARN_ON_ONCE(filter->n_preds)) {
/* We need to reset it now */
filter->n_preds = 0;
synchronize_sched();
}
__free_preds(filter);
}
}
@ -1328,6 +1341,30 @@ static int replace_system_preds(struct event_subsystem *system,
/* try to see if the filter can be applied */
err = replace_preds(call, filter, ps, filter_string, true);
if (err)
goto fail;
}
/* set all filter pred counts to zero */
list_for_each_entry(call, &ftrace_events, list) {
struct event_filter *filter = call->filter;
if (strcmp(call->class->system, system->name) != 0)
continue;
reset_preds(filter);
}
/*
* Since some of the preds may be used under preemption
* we need to wait for them to finish before we may
* reallocate them.
*/
synchronize_sched();
list_for_each_entry(call, &ftrace_events, list) {
struct event_filter *filter = call->filter;
if (strcmp(call->class->system, system->name) != 0)
continue;
/* really apply the filter */
@ -1342,11 +1379,13 @@ static int replace_system_preds(struct event_subsystem *system,
fail = false;
}
if (fail) {
parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
return -EINVAL;
}
if (fail)
goto fail;
return 0;
fail:
parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
return -EINVAL;
}
int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
@ -1381,6 +1420,13 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
goto out;
}
/*
* Make sure all the pred counts are zero so that
* no task is using it when we reallocate the preds array.
*/
reset_preds(call->filter);
synchronize_sched();
err = replace_preds(call, call->filter, ps, filter_string, false);
if (err)
append_filter_err(ps, call->filter);