fio: work with cgroup2 as well

The current code only works with cgroupv1, but as long as you don't want
to set blkio.weight or anything we can use the 'cgroup=' setting with
cgroupv2 easily with cgroupv1, we just need to write the thread pids to
a different file for cgroup2.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/backend.c b/backend.c
index c52eba58fa10eb4e02768a74d693cc2eee8b3241..a7e91843a0be087ff552d050a48aef8220cc2a8d 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -50,7 +50,7 @@
 
 static struct fio_sem *startup_sem;
 static struct flist_head *cgroup_list;
-static char *cgroup_mnt;
+static struct cgroup_mnt *cgroup_mnt;
 static int exit_value;
 static volatile int fio_abort;
 static unsigned int nr_process = 0;
@@ -1886,7 +1886,7 @@ err:
        close_and_free_files(td);
        cleanup_io_u(td);
        close_ioengine(td);
-       cgroup_shutdown(td, &cgroup_mnt);
+       cgroup_shutdown(td, cgroup_mnt);
        verify_free_state(td);
 
        if (td->zone_state_index) {
@@ -2508,7 +2508,6 @@ int fio_backend(struct sk_out *sk_out)
                cgroup_kill(cgroup_list);
                sfree(cgroup_list);
        }
-       sfree(cgroup_mnt);
 
        fio_sem_remove(startup_sem);
        stat_exit();

diff --git a/cgroup.c b/cgroup.c
index 629047b495b33c145ca545ac4856efdecaf78df5..77e31a4d0e222fd4f03ccbccb92a48a7c1457d9a 100644 (file)
--- a/cgroup.c
+++ b/cgroup.c
@@ -18,12 +18,13 @@ struct cgroup_member {
        unsigned int cgroup_nodelete;
 };
 
-static char *find_cgroup_mnt(struct thread_data *td)
+static struct cgroup_mnt *find_cgroup_mnt(struct thread_data *td)
 {
-       char *mntpoint = NULL;
+       struct cgroup_mnt *cgroup_mnt = NULL;
        struct mntent *mnt, dummy;
        char buf[256] = {0};
        FILE *f;
+       bool cgroup2 = false;
 
        f = setmntent("/proc/mounts", "r");
        if (!f) {
@@ -35,15 +36,29 @@ static char *find_cgroup_mnt(struct thread_data *td)
                if (!strcmp(mnt->mnt_type, "cgroup") &&
                    strstr(mnt->mnt_opts, "blkio"))
                        break;
+               if (!strcmp(mnt->mnt_type, "cgroup2")) {
+                       cgroup2 = true;
+                       break;
+               }
        }
 
-       if (mnt)
-               mntpoint = smalloc_strdup(mnt->mnt_dir);
-       else
+       if (mnt) {
+               cgroup_mnt = smalloc(sizeof(*cgroup_mnt));
+               if (cgroup_mnt) {
+                       cgroup_mnt->path = smalloc_strdup(mnt->mnt_dir);
+                       if (!cgroup_mnt->path) {
+                               sfree(cgroup_mnt);
+                               log_err("fio: could not allocate memory\n");
+                       } else {
+                               cgroup_mnt->cgroup2 = cgroup2;
+                       }
+               }
+       } else {
                log_err("fio: cgroup blkio does not appear to be mounted\n");
+       }
 
        endmntent(f);
-       return mntpoint;
+       return cgroup_mnt;
 }
 
 static void add_cgroup(struct thread_data *td, const char *name,
@@ -96,14 +111,14 @@ void cgroup_kill(struct flist_head *clist)
        fio_sem_up(lock);
 }
 
-static char *get_cgroup_root(struct thread_data *td, char *mnt)
+static char *get_cgroup_root(struct thread_data *td, struct cgroup_mnt *mnt)
 {
        char *str = malloc(64);
 
        if (td->o.cgroup)
-               sprintf(str, "%s/%s", mnt, td->o.cgroup);
+               sprintf(str, "%s/%s", mnt->path, td->o.cgroup);
        else
-               sprintf(str, "%s/%s", mnt, td->o.name);
+               sprintf(str, "%s/%s", mnt->path, td->o.name);
 
        return str;
 }
@@ -128,22 +143,25 @@ static int write_int_to_file(struct thread_data *td, const char *path,
 
 }
 
-static int cgroup_write_pid(struct thread_data *td, const char *root)
+static int cgroup_write_pid(struct thread_data *td, char *path, bool cgroup2)
 {
        unsigned int val = td->pid;
 
-       return write_int_to_file(td, root, "tasks", val, "cgroup write pid");
+       if (cgroup2)
+               return write_int_to_file(td, path, "cgroup.procs",
+                                        val, "cgroup write pid");
+       return write_int_to_file(td, path, "tasks", val, "cgroup write pid");
 }
 
 /*
  * Move pid to root class
  */
-static int cgroup_del_pid(struct thread_data *td, char *mnt)
+static int cgroup_del_pid(struct thread_data *td, struct cgroup_mnt *mnt)
 {
-       return cgroup_write_pid(td, mnt);
+       return cgroup_write_pid(td, mnt->path, mnt->cgroup2);
 }
 
-int cgroup_setup(struct thread_data *td, struct flist_head *clist, char **mnt)
+int cgroup_setup(struct thread_data *td, struct flist_head *clist, struct cgroup_mnt **mnt)
 {
        char *root;
 
@@ -172,13 +190,17 @@ int cgroup_setup(struct thread_data *td, struct flist_head *clist, char **mnt)
                add_cgroup(td, root, clist);
 
        if (td->o.cgroup_weight) {
+               if ((*mnt)->cgroup2) {
+                       log_err("fio: cgroup weit doesn't work with cgroup2\n");
+                       goto err;
+               }
                if (write_int_to_file(td, root, "blkio.weight",
                                        td->o.cgroup_weight,
                                        "cgroup open weight"))
                        goto err;
        }
 
-       if (!cgroup_write_pid(td, root)) {
+       if (!cgroup_write_pid(td, root, (*mnt)->cgroup2)) {
                free(root);
                return 0;
        }
@@ -188,14 +210,18 @@ err:
        return 1;
 }
 
-void cgroup_shutdown(struct thread_data *td, char **mnt)
+void cgroup_shutdown(struct thread_data *td, struct cgroup_mnt *mnt)
 {
-       if (*mnt == NULL)
+       if (mnt == NULL)
                return;
        if (!td->o.cgroup_weight && !td->o.cgroup)
-               return;
+               goto out;
 
-       cgroup_del_pid(td, *mnt);
+       cgroup_del_pid(td, mnt);
+out:
+       if (mnt->path)
+               sfree(mnt->path);
+       sfree(mnt);
 }
 
 static void fio_init cgroup_init(void)

diff --git a/cgroup.h b/cgroup.h
index 0bbe25a2cb79f720d843113c8ca07a3c002ac40f..5afac7f7551fe502670cc3b82cf2910a1374cc04 100644 (file)
--- a/cgroup.h
+++ b/cgroup.h
@@ -3,21 +3,28 @@
 
 #ifdef FIO_HAVE_CGROUPS
 
-int cgroup_setup(struct thread_data *, struct flist_head *, char **);
-void cgroup_shutdown(struct thread_data *, char **);
+struct cgroup_mnt {
+       char *path;
+       bool cgroup2;
+};
+
+int cgroup_setup(struct thread_data *, struct flist_head *, struct cgroup_mnt **);
+void cgroup_shutdown(struct thread_data *, struct cgroup_mnt *);
 
 void cgroup_kill(struct flist_head *list);
 
 #else
 
+struct cgroup_mnt;
+
 static inline int cgroup_setup(struct thread_data *td, struct flist_head *list,
-                              char **mnt)
+                              struct cgroup_mount **mnt)
 {
        td_verror(td, EINVAL, "cgroup_setup");
        return 1;
 }
 
-static inline void cgroup_shutdown(struct thread_data *td, char **mnt)
+static inline void cgroup_shutdown(struct thread_data *td, struct cgroup_mnt *mnt)
 {
 }