Module Name: src
Committed By: riastradh
Date: Sun Dec 19 10:58:29 UTC 2021
Added Files:
src/sys/external/bsd/drm2/include/drm: task_barrier.h
Log Message:
Reimplement task barrier without semaphores.
To generate a diff of this commit:
cvs rdiff -u -r0 -r1.1 src/sys/external/bsd/drm2/include/drm/task_barrier.h
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Added files:
Index: src/sys/external/bsd/drm2/include/drm/task_barrier.h
diff -u /dev/null src/sys/external/bsd/drm2/include/drm/task_barrier.h:1.1
--- /dev/null Sun Dec 19 10:58:29 2021
+++ src/sys/external/bsd/drm2/include/drm/task_barrier.h Sun Dec 19 10:58:29 2021
@@ -0,0 +1,120 @@
+/* $NetBSD: task_barrier.h,v 1.1 2021/12/19 10:58:29 riastradh Exp $ */
+
+/*-
+ * Copyright (c) 2020 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _DRM_TASK_BARRIER_H_
+#define _DRM_TASK_BARRIER_H_
+
+#include <sys/condvar.h>
+#include <sys/mutex.h>
+
+struct task_barrier {
+ kmutex_t tb_lock;
+ kcondvar_t tb_cv;
+ unsigned tb_cur;
+ unsigned tb_gen;
+ unsigned tb_max;
+};
+
+static inline void
+task_barrier_init(struct task_barrier *tb)
+{
+
+ mutex_init(&tb->tb_lock, MUTEX_DEFAULT, IPL_VM);
+ cv_init(&tb->tb_cv, "taskbar");
+ tb->tb_cur = 0;
+ tb->tb_gen = 0;
+ tb->tb_max = 0;
+}
+
+static inline void
+task_barrier_destroy(struct task_barrier *tb)
+{
+
+ KASSERT(tb->tb_cur == 0);
+ cv_destroy(&tb->tb_cv);
+ mutex_destroy(&tb->tb_lock);
+}
+
+static inline void
+task_barrier_add_task(struct task_barrier *tb)
+{
+
+ tb->tb_max++;
+}
+
+static inline void
+task_barrier_rem_task(struct task_barrier *tb)
+{
+
+ tb->tb_max--;
+}
+
+static inline void
+task_barrier_enter(struct task_barrier *tb)
+{
+
+ mutex_enter(&tb->tb_lock);
+ KASSERT(tb->tb_cur < tb->tb_max);
+ if (++tb->tb_cur < tb->tb_max) {
+ unsigned gen = tb->tb_gen;
+ do {
+ cv_wait(&tb->tb_cv, &tb->tb_lock);
+ } while (gen == tb->tb_gen);
+ } else {
+ tb->tb_gen++;
+ cv_broadcast(&tb->tb_cv);
+ }
+ mutex_exit(&tb->tb_lock);
+}
+
+static inline void
+task_barrier_exit(struct task_barrier *tb)
+{
+
+ mutex_enter(&tb->tb_lock);
+ KASSERT(tb->tb_cur > 0);
+ if (--tb->tb_cur > 0) {
+ unsigned gen = tb->tb_gen;
+ do {
+ cv_wait(&tb->tb_cv, &tb->tb_lock);
+ } while (gen == tb->tb_gen);
+ } else {
+ tb->tb_gen++;
+ cv_broadcast(&tb->tb_cv);
+ }
+}
+
+static inline void
+task_barrier_full(struct task_barrier *tb)
+{
+
+ task_barrier_enter(tb);
+ task_barrier_exit(tb);
+}
+
+#endif /* _DRM_TASK_BARRIER_H_ */
