The patch titled
cgroups: add simple listener of cgroup events to documentation
has been added to the -mm tree. Its filename is
cgroups-add-simple-listener-of-cgroup-events-to-documentation.patch
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See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: cgroups: add simple listener of cgroup events to documentation
From: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx>
Signed-off-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Dan Malek <dan@xxxxxxxxxxxxxxxxx>
Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/cgroups/cgroup_event_listener.c | 102 ++++++++++++++++
1 file changed, 102 insertions(+)
diff -puN /dev/null Documentation/cgroups/cgroup_event_listener.c
--- /dev/null
+++ a/Documentation/cgroups/cgroup_event_listener.c
@@ -0,0 +1,102 @@
+/*
+ * cgroup_event_listener.c - Simple listener of cgroup events
+ *
+ * Copyright (C) Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
+ */
+
+#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];
+ 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 = dprintf(event_control, "%d %d %s", efd, cfd, argv[2]);
+ 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 accessable 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);
+}
_
Patches currently in -mm which might be from kirill@xxxxxxxxxxxxx are
cgroups-fix-contents-in-cgroups-documentation.patch
cgroup-implement-eventfd-based-generic-api-for-notifications.patch
cgroup-implement-eventfd-based-generic-api-for-notifications-kconfig-fix.patch
cgroup-implement-eventfd-based-generic-api-for-notifications-fixes.patch
memcg-extract-mem_group_usage-from-mem_cgroup_read.patch
memcg-rework-usage-of-stats-by-soft-limit.patch
memcg-implement-memory-thresholds.patch
memcg-implement-memory-thresholds-checkpatch-fixes.patch
memcg-implement-memory-thresholds-checkpatch-fixes-fix.patch
memcg-implement-memory-thresholds-check-if-first-threshold-crossed.patch
memcg-typo-in-comment-to-mem_cgroup_print_oom_info.patch
memcg-update-threshold-and-softlimit-at-commit-v2.patch
memcg-share-event-counter-rather-than-duplicate-v2.patch
memcg-update-memcg_testtxt.patch
cgroups-fix-race-between-userspace-and-kernelspace.patch
cgroups-remove-events-before-destroying-subsystem-state-objects.patch
cgroups-add-simple-listener-of-cgroup-events-to-documentation.patch
memcg-update-memcg_testtxt-to-describe-memory-thresholds.patch
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