vendor: Add support for BFQIO cgroups
* Introduce a standalone libbfqio to be picked by inputflinger,
surfaceflinger and display HAL, without extending the VNDK.
* This commit is based on the following patches:
From: Steve Kondik <steve@cyngn.com>
Date: Tue, 08 Sep 2015 02:23:41 -0700
cutils: Add support for BFQIO cgroups
* Add support for a custom hierarchy of cgroups on top of the BFQ
IO scheduler. This allows us to place every thread into the
right class (realtime/best-effort/idle) with a set up priority
buckets depending on use case.
* The benefit of doing this is pretty incredible from an
interactivity standpoint. Realtime users (display/audio) benefit
the most, resulting in glitch-free audio and jank-free video.
Dexopting in the background no longer causes active harm to
foreground tasks. Other tasks such as account syncing become
invisible from the user's perspective.
* Magic bullet? Perhaps.
Change-Id: I4eb911395364ce46d6dcbff43e94286ded03a97d
From: Steve Kondik <steve@cyngn.com>
Date: Sat, 19 Sep 2015 12:43:40 -0700
cutils: Fix copypasta in ioprio code
Change-Id: I976693be4a6913ed2090fa32d0f8e4c93657e7e7
From: Steve Kondik <steve@cyngn.com>
Date: Sun, 20 Sep 2015 01:08:07 -0700
cutils: Fix display ioprio
* A few unwanted items are sneaking into this class resulting in
system slowdowns. Fixit.
Change-Id: I29033a38adf2c65535f916135d395d5147afe323
From: Steve Kondik <steve@cyngn.com>
Date: Sun, 20 Sep 2015 03:00:54 -0700
cutils: Clean up ioprio grouping
* It's now better understood what's happening system-wide due to these
changes, so clean up the stuff which is not necessary and/or
potentially harmful.
Change-Id: I72178770844c1ac388a0b424b12cdc49042aec87
From: Steve Kondik <steve@cyngn.com>
Date: Sun, 20 Sep 2015 17:36:54 -0700
cutils: Remove ioprio magic
* ..and replace it with something we can call explictly where it is
required in order to achieve the same goodness without the badness.
Change-Id: I605b3acbc56ce82663dd6f1c9f3320d0ab75e178
From: Zhao Wei Liew <zhaoweiliew@gmail.com>
Date: Thu, 08 Sep 2016 20:01:29 +0800
cutils: iosched_policy: Access BFQIO cgroup in /dev/bfqio
AOSP doesn't mount cgroups in /sys/fs/cgroup, but in /dev/.
Follow what AOSP does.
Change-Id: I40d2241e3e5c41612d3a54d22981d3250f8b1ed6
Change-Id: I7d42bd6bb9176724c1e5687de14946923150ae89
diff --git a/libbfqio/bfqio.c b/libbfqio/bfqio.c
new file mode 100644
index 0000000..131c78b
--- /dev/null
+++ b/libbfqio/bfqio.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2017 The LineageOS Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "bfqio"
+
+#include <fcntl.h>
+#include <cutils/iosched_policy.h>
+#include <cutils/log.h>
+#include <pthread.h>
+#include <sys/stat.h>
+
+static int __rtio_cgroup_supported = -1;
+static pthread_once_t __rtio_init_once = PTHREAD_ONCE_INIT;
+
+static void __initialize_rtio(void) {
+ if (!access("/dev/bfqio/tasks", W_OK) || !access("/dev/bfqio/rt-display/tasks", W_OK)) {
+ __rtio_cgroup_supported = 1;
+ } else {
+ __rtio_cgroup_supported = 0;
+ }
+}
+
+int android_set_rt_ioprio(int tid, int rt) {
+ int fd = -1, rc = -1;
+
+ pthread_once(&__rtio_init_once, __initialize_rtio);
+ if (__rtio_cgroup_supported != 1) {
+ return -1;
+ }
+
+ if (rt) {
+ fd = open("/dev/bfqio/rt-display/tasks", O_WRONLY | O_CLOEXEC);
+ } else {
+ fd = open("/dev/bfqio/tasks", O_WRONLY | O_CLOEXEC);
+ }
+
+ if (fd < 0) {
+ return -1;
+ }
+
+#ifdef HAVE_GETTID
+ if (tid == 0) {
+ tid = gettid();
+ }
+#endif
+
+ // specialized itoa -- works for tid > 0
+ char text[22];
+ char *end = text + sizeof(text) - 1;
+ char *ptr = end;
+ *ptr = '\0';
+ while (tid > 0) {
+ *--ptr = '0' + (tid % 10);
+ tid = tid / 10;
+ }
+
+ rc = write(fd, ptr, end - ptr);
+ if (rc < 0) {
+ /*
+ * If the thread is in the process of exiting,
+ * don't flag an error
+ */
+ if (errno == ESRCH) {
+ rc = 0;
+ } else {
+ SLOGV("android_set_rt_ioprio failed to write '%s' (%s); fd=%d\n",
+ ptr, strerror(errno), fd);
+ }
+ }
+
+ close(fd);
+ return rc;
+}