Commit 83db047d authored by Lucas De Marchi's avatar Lucas De Marchi
Browse files

drm/xe: Stop accumulating LRC timestamp on job_free 



The exec queue timestamp is only really useful when it's being queried
through the fdinfo. There's no need to update it so often, on every
job_free. Tracing a simple app like vkcube running shows an update
rate of ~ 120Hz. In case of discrete, the BO is on vram, creating a lot
of pcie transactions.

The update on job_free() is used to cover a gap: if exec
queue is created and destroyed rapidly, before a new query, the
timestamp still needs to be accumulated and accounted for in the xef.

Initial implementation in commit 6109f24f ("drm/xe: Add helper to
accumulate exec queue runtime") couldn't do it on the exec_queue_fini
since the xef could be gone at that point. However since commit
ce8c161c ("drm/xe: Add ref counting for xe_file") the xef is
refcounted and the exec queue always holds a reference, making this safe
now.

Improve the fix in commit 2149ded6 ("drm/xe: Fix use after free when
client stats are captured") by reducing the frequency in which the
update is needed.

Fixes: 2149ded6 ("drm/xe: Fix use after free when client stats are captured")
Reviewed-by: default avatarNirmoy Das <nirmoy.das@intel.com>
Reviewed-by: default avatarJonathan Cavitt <jonathan.cavitt@intel.com>
Reviewed-by: default avatarUmesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241104143815.2112272-3-lucas.demarchi@intel.com


Signed-off-by: default avatarLucas De Marchi <lucas.demarchi@intel.com>
parent a7238ee3

drivers/gpu/drm/xe/xe_exec_queue.c

+6 −0
Original line number Diff line number Diff line
@@ -260,8 +260,14 @@ void xe_exec_queue_fini(struct xe_exec_queue *q) 
{

	int i;



	/*

	 * Before releasing our ref to lrc and xef, accumulate our run ticks

	 */

	xe_exec_queue_update_run_ticks(q);



	for (i = 0; i < q->width; ++i)

		xe_lrc_put(q->lrc[i]);



	__xe_exec_queue_free(q);

}

drivers/gpu/drm/xe/xe_guc_submit.c

+0 −2
Original line number Diff line number Diff line
@@ -747,8 +747,6 @@ static void guc_exec_queue_free_job(struct drm_sched_job *drm_job) 
{

	struct xe_sched_job *job = to_xe_sched_job(drm_job);



	xe_exec_queue_update_run_ticks(job->q);



	trace_xe_sched_job_free(job);

	xe_sched_job_put(job);

}