From 39f22027248f658ade599e89c2fe6afae02ac9d7 Mon Sep 17 00:00:00 2001
From: Jens Axboe <jens.axboe@oracle.com>
Date: Fri, 4 Dec 2009 11:29:12 +0100
Subject: [PATCH] Better support for setting up and removing private cgroups

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
 cgroup.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++----------
 cgroup.h |  6 ++++
 fio.c    |  2 ++
 fio.h    |  1 -
 4 files changed, 81 insertions(+), 17 deletions(-)

diff --git a/cgroup.c b/cgroup.c
index 548740a0..b0c7ea20 100644
--- a/cgroup.c
+++ b/cgroup.c
@@ -4,7 +4,59 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include "fio.h"
+#include "flist.h"
 #include "cgroup.h"
+#include "smalloc.h"
+
+static struct flist_head *cgroup_list;
+static struct fio_mutex *lock;
+
+struct cgroup_member {
+	struct flist_head list;
+	char *root;
+};
+
+static void add_cgroup(const char *name)
+{
+	struct cgroup_member *cm;
+
+	cm = smalloc(sizeof(*cm));
+	INIT_FLIST_HEAD(&cm->list);
+	cm->root = smalloc_strdup(name);
+
+	fio_mutex_down(lock);
+
+	if (!cgroup_list) {
+		cgroup_list = smalloc(sizeof(struct flist_head));
+		INIT_FLIST_HEAD(cgroup_list);
+	}
+
+	flist_add_tail(&cm->list, cgroup_list);
+	fio_mutex_up(lock);
+}
+
+void cgroup_kill(void)
+{
+	struct flist_head *n, *tmp;
+	struct cgroup_member *cm;
+
+	fio_mutex_down(lock);
+	if (!cgroup_list)
+		goto out;
+
+	flist_for_each_safe(n, tmp, cgroup_list) {
+		cm = flist_entry(n, struct cgroup_member, list);
+		rmdir(cm->root);
+		flist_del(&cm->list);
+		sfree(cm->root);
+		sfree(cm);
+	}
+
+	sfree(cgroup_list);
+	cgroup_list = NULL;
+out:
+	fio_mutex_up(lock);
+}
 
 /*
  * Check if the given root appears valid
@@ -40,7 +92,6 @@ static int cgroup_add_pid(struct thread_data *td)
 
 	root = get_cgroup_root(td);
 	sprintf(tmp, "%s/tasks", root);
-
 	f = fopen(tmp, "w");
 	if (!f) {
 		td_verror(td, errno, "cgroup open tasks");
@@ -97,17 +148,20 @@ int cgroup_setup(struct thread_data *td)
 			return 1;
 		}
 	} else
-		td->o.cgroup_was_created = 1;
+		add_cgroup(root);
 
-	sprintf(tmp, "%s/blkio.weight", root);
-	f = fopen(tmp, "w");
-	if (!f) {
-		td_verror(td, errno, "cgroup open weight");
-		return 1;
+	if (td->o.cgroup_weight) {
+		sprintf(tmp, "%s/blkio.weight", root);
+		f = fopen(tmp, "w");
+		if (!f) {
+			td_verror(td, errno, "cgroup open weight");
+			return 1;
+		}
+
+		fprintf(f, "%d", td->o.cgroup_weight);
+		fclose(f);
 	}
 
-	fprintf(f, "%d", td->o.cgroup_weight);
-	fclose(f);
 	free(root);
 
 	if (cgroup_add_pid(td))
@@ -120,16 +174,19 @@ void cgroup_shutdown(struct thread_data *td)
 {
 	if (cgroup_check_fs(td))
 		return;
-	if (!td->o.cgroup_weight)
+	if (!td->o.cgroup_weight && td->o.cgroup)
 		return;
 
 	cgroup_del_pid(td);
+}
 
-	if (td->o.cgroup_was_created) {
-		char *root;
 
-		root = get_cgroup_root(td);
-		rmdir(root);
-		free(root);
-	}
+static void fio_init cgroup_init(void)
+{
+	lock = fio_mutex_init(1);
+}
+
+static void fio_exit cgroup_exit(void)
+{
+	fio_mutex_remove(lock);
 }
diff --git a/cgroup.h b/cgroup.h
index 65fa3ad1..1c67ba80 100644
--- a/cgroup.h
+++ b/cgroup.h
@@ -6,6 +6,8 @@
 int cgroup_setup(struct thread_data *td);
 void cgroup_shutdown(struct thread_data *td);
 
+void cgroup_kill(void);
+
 #else
 
 static inline int cgroup_setup(struct thread_data *td)
@@ -18,5 +20,9 @@ static inline void cgroup_shutdown(struct thread_data *td)
 {
 }
 
+void cgroup_kill(void)
+{
+}
+
 #endif
 #endif
diff --git a/fio.c b/fio.c
index 4bbab5af..a18ca1b6 100644
--- a/fio.c
+++ b/fio.c
@@ -1668,6 +1668,8 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	cgroup_kill();
+
 	fio_mutex_remove(startup_mutex);
 	fio_mutex_remove(writeout_mutex);
 	return exit_value;
diff --git a/fio.h b/fio.h
index aa5124cd..17aeaada 100644
--- a/fio.h
+++ b/fio.h
@@ -278,7 +278,6 @@ struct thread_options {
 	char *cgroup_root;
 	char *cgroup;
 	unsigned int cgroup_weight;
-	unsigned int cgroup_was_created;
 };
 
 #define FIO_VERROR_SIZE	128
-- 
2.25.1