1 /*
2 * Copyright (C) 2018 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define LOG_TAG "libpsi"
18
19 #include <errno.h>
20 #include <string.h>
21 #include <sys/epoll.h>
22
23 #include <log/log.h>
24 #include "psi/psi.h"
25
26 #define PSI_MON_FILE_MEMORY "/proc/pressure/memory"
27
28 static const char* stall_type_name[] = {
29 "some",
30 "full",
31 };
32
init_psi_monitor(enum psi_stall_type stall_type,int threshold_us,int window_us)33 int init_psi_monitor(enum psi_stall_type stall_type,
34 int threshold_us, int window_us) {
35 int fd;
36 int res;
37 char buf[256];
38
39 fd = TEMP_FAILURE_RETRY(open(PSI_MON_FILE_MEMORY, O_WRONLY | O_CLOEXEC));
40 if (fd < 0) {
41 ALOGE("No kernel psi monitor support (errno=%d)", errno);
42 return -1;
43 }
44
45 switch (stall_type) {
46 case (PSI_SOME):
47 case (PSI_FULL):
48 res = snprintf(buf, sizeof(buf), "%s %d %d",
49 stall_type_name[stall_type], threshold_us, window_us);
50 break;
51 default:
52 ALOGE("Invalid psi stall type: %d", stall_type);
53 errno = EINVAL;
54 goto err;
55 }
56
57 if (res >= (ssize_t)sizeof(buf)) {
58 ALOGE("%s line overflow for psi stall type '%s'",
59 PSI_MON_FILE_MEMORY, stall_type_name[stall_type]);
60 errno = EINVAL;
61 goto err;
62 }
63
64 res = TEMP_FAILURE_RETRY(write(fd, buf, strlen(buf) + 1));
65 if (res < 0) {
66 ALOGE("%s write failed for psi stall type '%s'; errno=%d",
67 PSI_MON_FILE_MEMORY, stall_type_name[stall_type], errno);
68 goto err;
69 }
70
71 return fd;
72
73 err:
74 close(fd);
75 return -1;
76 }
77
register_psi_monitor(int epollfd,int fd,void * data)78 int register_psi_monitor(int epollfd, int fd, void* data) {
79 int res;
80 struct epoll_event epev;
81
82 epev.events = EPOLLPRI;
83 epev.data.ptr = data;
84 res = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &epev);
85 if (res < 0) {
86 ALOGE("epoll_ctl for psi monitor failed; errno=%d", errno);
87 }
88 return res;
89 }
90
unregister_psi_monitor(int epollfd,int fd)91 int unregister_psi_monitor(int epollfd, int fd) {
92 return epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, NULL);
93 }
94
destroy_psi_monitor(int fd)95 void destroy_psi_monitor(int fd) {
96 if (fd >= 0) {
97 close(fd);
98 }
99 }
100