cgroups: move cgroup_event_listener.c to tools/cgroup

Move the cgroup_event_listener.c tool from Documentation into the new
tools/cgroup directory.

This change involves wiring cgroup_event_listener.c into the tools/
make system so that is can be built with:
  $ make tools/cgroup

Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Greg Thelen
2013-01-04 13:05:17 -08:00
committed by Tejun Heo
parent 12a9d2fef1
commit 92e015b1cf
6 changed files with 23 additions and 13 deletions

View File

@@ -4,8 +4,6 @@ blkio-controller.txt
- Description for Block IO Controller, implementation and usage details.
cgroups.txt
- Control Groups definition, implementation details, examples and API.
cgroup_event_listener.c
- A user program for cgroup listener.
cpuacct.txt
- CPU Accounting Controller; account CPU usage for groups of tasks.
cpusets.txt

View File

@@ -1,110 +0,0 @@
/*
* cgroup_event_listener.c - Simple listener of cgroup events
*
* Copyright (C) Kirill A. Shutemov <kirill@shutemov.name>
*/
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/eventfd.h>
#define USAGE_STR "Usage: cgroup_event_listener <path-to-control-file> <args>\n"
int main(int argc, char **argv)
{
int efd = -1;
int cfd = -1;
int event_control = -1;
char event_control_path[PATH_MAX];
char line[LINE_MAX];
int ret;
if (argc != 3) {
fputs(USAGE_STR, stderr);
return 1;
}
cfd = open(argv[1], O_RDONLY);
if (cfd == -1) {
fprintf(stderr, "Cannot open %s: %s\n", argv[1],
strerror(errno));
goto out;
}
ret = snprintf(event_control_path, PATH_MAX, "%s/cgroup.event_control",
dirname(argv[1]));
if (ret >= PATH_MAX) {
fputs("Path to cgroup.event_control is too long\n", stderr);
goto out;
}
event_control = open(event_control_path, O_WRONLY);
if (event_control == -1) {
fprintf(stderr, "Cannot open %s: %s\n", event_control_path,
strerror(errno));
goto out;
}
efd = eventfd(0, 0);
if (efd == -1) {
perror("eventfd() failed");
goto out;
}
ret = snprintf(line, LINE_MAX, "%d %d %s", efd, cfd, argv[2]);
if (ret >= LINE_MAX) {
fputs("Arguments string is too long\n", stderr);
goto out;
}
ret = write(event_control, line, strlen(line) + 1);
if (ret == -1) {
perror("Cannot write to cgroup.event_control");
goto out;
}
while (1) {
uint64_t result;
ret = read(efd, &result, sizeof(result));
if (ret == -1) {
if (errno == EINTR)
continue;
perror("Cannot read from eventfd");
break;
}
assert(ret == sizeof(result));
ret = access(event_control_path, W_OK);
if ((ret == -1) && (errno == ENOENT)) {
puts("The cgroup seems to have removed.");
ret = 0;
break;
}
if (ret == -1) {
perror("cgroup.event_control "
"is not accessible any more");
break;
}
printf("%s %s: crossed\n", argv[1], argv[2]);
}
out:
if (efd >= 0)
close(efd);
if (event_control >= 0)
close(event_control);
if (cfd >= 0)
close(cfd);
return (ret != 0);
}

View File

@@ -399,8 +399,7 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
9.10 Memory thresholds
Memory controller implements memory thresholds using cgroups notification
API. You can use Documentation/cgroups/cgroup_event_listener.c to test
it.
API. You can use tools/cgroup/cgroup_event_listener.c to test it.
(Shell-A) Create cgroup and run event listener
# mkdir /cgroup/A