On 3/23/21 12:16 PM, Thierry Reding wrote:
On Mon, Jan 11, 2021 at 03:00:01PM +0200, Mikko Perttunen wrote:
Show the number of pending waiters in the debugfs status file.
This is useful for testing to verify that waiters do not leak
or accumulate incorrectly.
Signed-off-by: Mikko Perttunen <mperttunen@xxxxxxxxxx>
---
drivers/gpu/host1x/debug.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/host1x/debug.c b/drivers/gpu/host1x/debug.c
index 1b4997bda1c7..8a14880c61bb 100644
--- a/drivers/gpu/host1x/debug.c
+++ b/drivers/gpu/host1x/debug.c
@@ -69,6 +69,7 @@ static int show_channel(struct host1x_channel *ch, void *data, bool show_fifo)
static void show_syncpts(struct host1x *m, struct output *o)
{
+ struct list_head *pos;
unsigned int i;
host1x_debug_output(o, "---- syncpts ----\n");
@@ -76,12 +77,19 @@ static void show_syncpts(struct host1x *m, struct output *o)
for (i = 0; i < host1x_syncpt_nb_pts(m); i++) {
u32 max = host1x_syncpt_read_max(m->syncpt + i);
u32 min = host1x_syncpt_load(m->syncpt + i);
+ unsigned int waiters = 0;
- if (!min && !max)
+ spin_lock(&m->syncpt[i].intr.lock);
+ list_for_each(pos, &m->syncpt[i].intr.wait_head)
+ waiters++;
+ spin_unlock(&m->syncpt[i].intr.lock);
Would it make sense to keep a running count so that we don't have to
compute it here?
Considering this is just a debug facility, I think I prefer not adding a
new field just for it.
+
+ if (!min && !max && !waiters)
continue;
- host1x_debug_output(o, "id %u (%s) min %d max %d\n",
- i, m->syncpt[i].name, min, max);
+ host1x_debug_output(o,
+ "id %u (%s) min %d max %d (%d waiters)\n",
+ i, m->syncpt[i].name, min, max, waiters);
Or alternatively, would it be useful to collect a bit more information
about waiters so that when they leak we get a better understanding of
which ones leak?
It doesn't look like we currently have much information in struct
host1x_waitlist to identify waiters, but perhaps that can be extended?
I added this patch mainly for use with integration tests, so they can
verify no waiters leaked in negative tests. I think let's put off adding
other information until there's some need for it.
Mikko
Thierry
