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/*
* Copyright (C) 2018 The Android Open Source 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 "libpsi"
#include <errno.h>
#include <string.h>
#include <sys/epoll.h>
#include <log/log.h>
#include "psi/psi.h"
#define PSI_MON_FILE_MEMORY "/proc/pressure/memory"
static const char* stall_type_name[] = {
"some",
"full",
};
int init_psi_monitor(enum psi_stall_type stall_type,
int threshold_us, int window_us) {
int fd;
int res;
char buf[256];
fd = TEMP_FAILURE_RETRY(open(PSI_MON_FILE_MEMORY, O_WRONLY | O_CLOEXEC));
if (fd < 0) {
ALOGE("No kernel psi monitor support (errno=%d)", errno);
return -1;
}
switch (stall_type) {
case (PSI_SOME):
case (PSI_FULL):
res = snprintf(buf, sizeof(buf), "%s %d %d",
stall_type_name[stall_type], threshold_us, window_us);
break;
default:
ALOGE("Invalid psi stall type: %d", stall_type);
errno = EINVAL;
goto err;
}
if (res >= (ssize_t)sizeof(buf)) {
ALOGE("%s line overflow for psi stall type '%s'",
PSI_MON_FILE_MEMORY, stall_type_name[stall_type]);
errno = EINVAL;
goto err;
}
res = TEMP_FAILURE_RETRY(write(fd, buf, strlen(buf) + 1));
if (res < 0) {
ALOGE("%s write failed for psi stall type '%s'; errno=%d",
PSI_MON_FILE_MEMORY, stall_type_name[stall_type], errno);
goto err;
}
return fd;
err:
close(fd);
return -1;
}
int register_psi_monitor(int epollfd, int fd, void* data) {
int res;
struct epoll_event epev;
epev.events = EPOLLPRI;
epev.data.ptr = data;
res = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &epev);
if (res < 0) {
ALOGE("epoll_ctl for psi monitor failed; errno=%d", errno);
}
return res;
}
int unregister_psi_monitor(int epollfd, int fd) {
return epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, NULL);
}
void destroy_psi_monitor(int fd) {
if (fd >= 0) {
close(fd);
}
}
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