87 lines
2.2 KiB
C
87 lines
2.2 KiB
C
/*
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* Copyright (C) 2017 The LineageOS Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#define LOG_TAG "bfqio"
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#include <fcntl.h>
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#include <cutils/iosched_policy.h>
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#include <cutils/log.h>
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#include <pthread.h>
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#include <sys/stat.h>
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#include <unistd.h>
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static int __rtio_cgroup_supported = -1;
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static pthread_once_t __rtio_init_once = PTHREAD_ONCE_INIT;
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static void __initialize_rtio(void) {
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if (!access("/dev/bfqio/tasks", W_OK) || !access("/dev/bfqio/rt-display/tasks", W_OK)) {
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__rtio_cgroup_supported = 1;
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} else {
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__rtio_cgroup_supported = 0;
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}
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}
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int android_set_rt_ioprio(int tid, int rt) {
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int fd = -1, rc = -1;
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pthread_once(&__rtio_init_once, __initialize_rtio);
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if (__rtio_cgroup_supported != 1) {
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return -1;
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}
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if (rt) {
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fd = open("/dev/bfqio/rt-display/tasks", O_WRONLY | O_CLOEXEC);
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} else {
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fd = open("/dev/bfqio/tasks", O_WRONLY | O_CLOEXEC);
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}
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if (fd < 0) {
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return -1;
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}
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#ifdef HAVE_GETTID
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if (tid == 0) {
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tid = gettid();
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}
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#endif
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// specialized itoa -- works for tid > 0
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char text[22];
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char *end = text + sizeof(text) - 1;
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char *ptr = end;
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*ptr = '\0';
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while (tid > 0) {
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*--ptr = '0' + (tid % 10);
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tid = tid / 10;
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}
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rc = write(fd, ptr, end - ptr);
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if (rc < 0) {
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/*
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* If the thread is in the process of exiting,
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* don't flag an error
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*/
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if (errno == ESRCH) {
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rc = 0;
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} else {
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SLOGV("android_set_rt_ioprio failed to write '%s' (%s); fd=%d\n",
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ptr, strerror(errno), fd);
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}
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}
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close(fd);
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return rc;
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}
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