[Devel] [PATCH 6/7] ve/cgroup: Set release_agent_path for root cgroups separately for each ve.
Pavel Tikhomirov
ptikhomirov at virtuozzo.com
Thu Apr 2 13:28:23 MSK 2020
On 4/1/20 6:41 PM, Valeriy Vdovin wrote:
> https://jira.sw.ru/browse/PSBM-83887
> Signed-off-by: Valeriy Vdovin <valeriy.vdovin at virtuozzo.com>
> ---
> include/linux/cgroup.h | 5 +--
> include/linux/ve.h | 7 ++++
> kernel/cgroup.c | 108 ++++++++++++++++++++++++++++++++++++++++---------
> kernel/ve/ve.c | 61 +++++++++++++++++++++++++++-
> 4 files changed, 158 insertions(+), 23 deletions(-)
>
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index 86d3e5d..25e2bbd 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -417,9 +417,6 @@ struct cgroupfs_root {
> /* IDs for cgroups in this hierarchy */
> struct ida cgroup_ida;
>
> - /* The path to use for release notifications. */
> - char release_agent_path[PATH_MAX];
> -
> /* The name for this hierarchy - may be empty */
> char name[MAX_CGROUP_ROOT_NAMELEN];
> };
> @@ -663,7 +660,7 @@ int cgroup_task_count(const struct cgroup *cgrp);
> void cgroup_release_agent(struct work_struct *work);
>
> #ifdef CONFIG_VE
> -void cgroup_mark_ve_root(struct ve_struct *ve);
> +int cgroup_mark_ve_root(struct ve_struct *ve);
> void cgroup_unbind_roots_from_ve(struct ve_struct *ve);
> #endif
>
> diff --git a/include/linux/ve.h b/include/linux/ve.h
> index 12b5873..bb6602d 100644
> --- a/include/linux/ve.h
> +++ b/include/linux/ve.h
> @@ -214,6 +214,13 @@ void do_update_load_avg_ve(void);
>
> void ve_add_to_release_list(struct ve_struct *ve, struct cgroup *cgrp);
> void ve_rm_from_release_list(struct ve_struct *ve, struct cgroup *cgrp);
> +
> +int ve_set_release_agent_path(struct ve_struct *ve, struct cgroup *cgroot,
> + const char *release_agent);
> +
> +const char *ve_get_release_agent_path(struct ve_struct *ve,
> + struct cgroup *cgrp_root);
> +
> extern struct ve_struct *get_ve(struct ve_struct *ve);
> extern void put_ve(struct ve_struct *ve);
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 680ec8e..b2fa6a2 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -1081,10 +1081,16 @@ static int rebind_subsystems(struct cgroupfs_root *root,
>
> static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry)
> {
> + const char *release_agent;
> struct cgroupfs_root *root = dentry->d_sb->s_fs_info;
> struct cgroup_subsys *ss;
> + struct cgroup *root_cgrp = &root->top_cgroup;
>
> +#ifdef CONFIG_VE
> + struct ve_struct *ve = get_exec_env();
> +#endif
> mutex_lock(&cgroup_root_mutex);
> +
> for_each_subsys(root, ss)
> seq_printf(seq, ",%s", ss->name);
> if (root->flags & CGRP_ROOT_SANE_BEHAVIOR)
> @@ -1095,9 +1101,18 @@ static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry)
> seq_puts(seq, ",xattr");
> if (root->flags & CGRP_ROOT_CPUSET_V2_MODE)
> seq_puts(seq, ",cpuset_v2_mode");
> - if (strlen(root->release_agent_path))
> - seq_show_option(seq, "release_agent",
> - root->release_agent_path);
> +#ifdef CONFIG_VE
> + if (!ve_is_super(ve)) {
> + mutex_lock(&cgroup_mutex);
> + root_cgrp = task_cgroup_from_root(ve->init_task, root);
Why not "css_cgroup_from_root(ve->root_css_set, root);" instead?
> + mutex_unlock(&cgroup_mutex);
> + }
> +#endif
> + rcu_read_lock();
> + release_agent = ve_get_release_agent_path(root_cgrp->ve_owner, root_cgrp);
> + if (release_agent && release_agent[0])
> + seq_show_option(seq, "release_agent", release_agent);
> + rcu_read_unlock();
> if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->top_cgroup.flags))
> seq_puts(seq, ",clone_children");
> if (strlen(root->name))
> @@ -1375,8 +1390,13 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data)
> /* re-populate subsystem files */
> cgroup_populate_dir(cgrp, false, added_mask);
>
> - if (opts.release_agent)
> - strcpy(root->release_agent_path, opts.release_agent);
> + if (opts.release_agent) {
> + struct cgroup *root_cgrp;
> + root_cgrp = cgroup_get_local_root(cgrp);
> + if (root_cgrp->ve_owner)
> + ret = ve_set_release_agent_path(root_cgrp->ve_owner,
> + root_cgrp, opts.release_agent);
> + }
> out_unlock:
> kfree(opts.release_agent);
> kfree(opts.name);
> @@ -1537,8 +1557,6 @@ static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts)
> root->subsys_mask = opts->subsys_mask;
> root->flags = opts->flags;
> ida_init(&root->cgroup_ida);
> - if (opts->release_agent)
> - strcpy(root->release_agent_path, opts->release_agent);
> if (opts->name)
> strcpy(root->name, opts->name);
> if (opts->cpuset_clone_children)
> @@ -2304,27 +2322,44 @@ static int cgroup_procs_write(struct cgroup *cgrp, struct cftype *cft, u64 tgid)
> static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft,
> const char *buffer)
> {
> - BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
> -
> + int ret = 0;
> + struct cgroup *root_cgrp;
> if (strlen(buffer) >= PATH_MAX)
> return -EINVAL;
>
> if (!cgroup_lock_live_group(cgrp))
> return -ENODEV;
>
> - mutex_lock(&cgroup_root_mutex);
> - strcpy(cgrp->root->release_agent_path, buffer);
> - mutex_unlock(&cgroup_root_mutex);
> + root_cgrp = cgroup_get_local_root(cgrp);
> + BUG_ON(!root_cgrp);
> + if (root_cgrp->ve_owner) {
> + ret = ve_set_release_agent_path(root_cgrp->ve_owner,
> + root_cgrp, buffer);
> + }
> +
> mutex_unlock(&cgroup_mutex);
> - return 0;
> + return ret;
> }
>
> static int cgroup_release_agent_show(struct cgroup *cgrp, struct cftype *cft,
> struct seq_file *seq)
> {
> + const char *release_agent;
> + struct cgroup *root_cgrp;
> +
> if (!cgroup_lock_live_group(cgrp))
> return -ENODEV;
> - seq_puts(seq, cgrp->root->release_agent_path);
> +
> + root_cgrp = cgroup_get_local_root(cgrp);
> + if (root_cgrp->ve_owner) {
> + rcu_read_lock();
> + release_agent = ve_get_release_agent_path(
> + root_cgrp->ve_owner, root_cgrp);
> +
> + if (release_agent)
> + seq_puts(seq, release_agent);
> + rcu_read_unlock();
> + }
> seq_putc(seq, '\n');
> mutex_unlock(&cgroup_mutex);
> return 0;
> @@ -4140,7 +4175,7 @@ static struct cftype files[] = {
> },
> {
> .name = "release_agent",
> - .flags = CFTYPE_ONLY_ON_ROOT,
> + .flags = CFTYPE_ONLY_ON_ROOT | CFTYPE_VE_WRITABLE,
> .read_seq_string = cgroup_release_agent_show,
> .write_string = cgroup_release_agent_write,
> .max_write_len = PATH_MAX,
> @@ -4344,22 +4379,53 @@ static int subgroups_count(struct cgroup *cgroup)
> return cgrps_count;
> }
>
> +static struct cftype *get_cftype_by_name(const char *name)
> +{
> + struct cftype *cft;
> + for (cft = files; cft->name[0] != '\0'; cft++) {
> + if (!strcmp(cft->name, name))
> + return cft;
> + }
> + return NULL;
> +}
> +
> +static int cgroup_add_file_on_mark_ve(struct cgroup *ve_root)
> +{
> + int err;
> + struct dentry *dir = ve_root->dentry;
> + struct cftype *cft = get_cftype_by_name("release_agent");
> + BUG_ON(!cft);
> +
> + mutex_lock(&dir->d_inode->i_mutex);
> + err = cgroup_add_file(ve_root, NULL, cft);
> + mutex_unlock(&dir->d_inode->i_mutex);
> + if (err) {
> + pr_warn("cgroup_addrm_files: failed to add %s, err=%d\n",
> + cft->name, err);
> + }
> + return err;
> +}
> +
> #ifdef CONFIG_VE
> -void cgroup_mark_ve_root(struct ve_struct *ve)
> +int cgroup_mark_ve_root(struct ve_struct *ve)
> {
> struct cgroup *cgrp;
> struct cgroupfs_root *root;
> + int err = 0;
>
> mutex_lock(&cgroup_mutex);
> for_each_active_root(root) {
> cgrp = task_cgroup_from_root(ve->init_task, root);
> cgrp->ve_owner = ve;
> set_bit(CGRP_VE_ROOT, &cgrp->flags);
> -
> + err = cgroup_add_file_on_mark_ve(cgrp);
> + if (err)
> + break;
> if (test_bit(cpu_cgroup_subsys_id, &root->subsys_mask))
> link_ve_root_cpu_cgroup(cgrp);
> }
> mutex_unlock(&cgroup_mutex);
> + return err;
> }
>
> void cgroup_unbind_roots_from_ve(struct ve_struct *ve)
> @@ -5516,7 +5582,13 @@ void cgroup_release_agent(struct work_struct *work)
> goto continue_free;
> if (__cgroup_path(cgrp, pathbuf, PAGE_SIZE, 1) < 0)
> goto continue_free;
> - agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
> +
> + rcu_read_lock();
> + root_cgrp = cgroup_get_local_root(cgrp);
> + release_agent = ve_get_release_agent_path(ve, root_cgrp);
> + if (release_agent)
> + agentbuf = kstrdup(release_agent, GFP_KERNEL);
> + rcu_read_unlock();
> if (!agentbuf)
> goto continue_free;
>
> diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
> index 0136bf2..d2edfc0 100644
> --- a/kernel/ve/ve.c
> +++ b/kernel/ve/ve.c
> @@ -51,6 +51,11 @@ struct per_cgroot_data {
> * data is related to this cgroup
> */
> struct cgroup *cgroot;
> + /*
> + * path to release agent binaray, that should
> + * be spawned for all cgroups under this cgroup root
> + */
> + struct cgroup_rcu_string __rcu *release_agent_path;
> };
>
> extern struct kmapset_set sysfs_ve_perms_set;
> @@ -152,6 +157,58 @@ static struct per_cgroot_data *per_cgroot_data_new_locked(
> return data;
> }
>
> +int ve_set_release_agent_path(struct ve_struct *ve,
> + struct cgroup *cgroot, const char *release_agent)
> +{
> + struct per_cgroot_data *data;
> + struct cgroup_rcu_string *new_path, *old_path;
> +
> + new_path = cgroup_rcu_strdup(release_agent, strlen(release_agent));
> + if (!new_path)
> + return -ENOMEM;
> +
> + raw_spin_lock(&ve->per_cgroot_list_lock);
> + data = per_cgroot_data_find_locked(&ve->per_cgroot_list, cgroot);
> + if (!data) {
> + data = per_cgroot_data_new_locked(&ve->per_cgroot_list,
> + cgroot);
> + if (IS_ERR(data)) {
> + kfree_rcu(new_path, rcu_head);
> + raw_spin_unlock(&ve->per_cgroot_list_lock);
> + return PTR_ERR(data);
> + }
> + }
> +
> + old_path = data->release_agent_path;
> + rcu_assign_pointer(data->release_agent_path, new_path);
> +
> + raw_spin_unlock(&ve->per_cgroot_list_lock);
> +
> + if (old_path)
> + kfree_rcu(old_path, rcu_head);
> + return 0;
> +}
> +
> +const char *ve_get_release_agent_path(struct ve_struct *ve, struct cgroup *cgroot)
> +{
> + const char *result = NULL;
> + struct per_cgroot_data *data;
> + struct cgroup_rcu_string *str;
> +
> + raw_spin_lock(&ve->per_cgroot_list_lock);
> +
> + data = per_cgroot_data_find_locked(&ve->per_cgroot_list, cgroot);
> + if (!data)
> + goto unlock;
> +
> + str = rcu_dereference(data->release_agent_path);
> + if (str)
> + result = str->val;
> +unlock:
> + raw_spin_unlock(&ve->per_cgroot_list_lock);
> + return result;
> +}
> +
> struct cgroup_subsys_state *ve_get_init_css(struct ve_struct *ve, int subsys_id)
> {
> struct cgroup_subsys_state *css, *tmp;
> @@ -643,7 +700,9 @@ static int ve_start_container(struct ve_struct *ve)
> if (err < 0)
> goto err_iterate;
>
> - cgroup_mark_ve_root(ve);
> + err = cgroup_mark_ve_root(ve);
> + if (err)
> + goto err_mark_ve;
>
> err = ve_workqueue_start(ve);
> if (err)
>
--
Best regards, Tikhomirov Pavel
Software Developer, Virtuozzo.
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