commit 85040434bec9856c6dd8578fecade222bfe95431
author Tim Murray <timmurray@google.com> Mon Feb 20 15:59:32 2017 +0530
committer Lynus Vaz <lvaz@codeaurora.org> Wed Jul 12 19:20:44 2017 +0530
tree e9210c9a4d87fa5065feef2531d3ad975622e915
parent e011825f80c98c177531e1d6a715cba12d29b541

msm: kgsl: convert some workqueues to use kthreads.

adreno_dispatch_work and _kgsl_event_worker are both low-latency
low-runtime functions that are in the critical path of GPU
rendering. Moving them out of workqueues and into a dedicated FIFO
kthread avoids significant jitter.

bug 30342017

Git-commit: 1a7a93bd33f48a369de29f6f2b56251127bf6ab4
Git-repo: https://android.googlesource.com/kernel/msm

Change-Id: I83562f488c34c2ab001c8ea79e7f09b633c658bd
Signed-off-by: Tim Murray <timmurray@google.com>
Signed-off-by: Abhilash Kumar <krabhi@codeaurora.org>
Signed-off-by: Lynus Vaz <lvaz@codeaurora.org>

drivers/gpu/msm/kgsl.c

diff --git a/drivers/gpu/msm/kgsl.c b/drivers/gpu/msm/kgsl.c
index 4e67efb..38c9e70 100644
--- a/drivers/gpu/msm/kgsl.c
+++ b/drivers/gpu/msm/kgsl.c
@@ -4786,6 +4786,8 @@
 static int __init kgsl_core_init(void)
 {
 	int result = 0;
+	struct sched_param param = { .sched_priority = 2 };
+
 	/* alloc major and minor device numbers */
 	result = alloc_chrdev_region(&kgsl_driver.major, 0, KGSL_DEVICE_MAX,
 		"kgsl");
@@ -4852,6 +4854,18 @@
 	kgsl_driver.mem_workqueue = alloc_workqueue("kgsl-mementry",
 		WQ_UNBOUND | WQ_MEM_RECLAIM, 0);
 
+	kthread_init_worker(&kgsl_driver.worker);
+
+	kgsl_driver.worker_thread = kthread_run(kthread_worker_fn,
+		&kgsl_driver.worker, "kgsl_worker_thread");
+
+	if (IS_ERR(kgsl_driver.worker_thread)) {
+		pr_err("unable to start kgsl thread\n");
+		goto err;
+	}
+
+	sched_setscheduler(kgsl_driver.worker_thread, SCHED_FIFO, &param);
+
 	kgsl_events_init();
 
 	result = kgsl_drawobjs_cache_init();