aboutsummaryrefslogtreecommitdiff
path: root/kernel/cgroup/cgroup.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/cgroup/cgroup.c')
-rw-r--r--kernel/cgroup/cgroup.c108
1 files changed, 78 insertions, 30 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 7a8429f8e280..f31bd61c9466 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -86,6 +86,7 @@ EXPORT_SYMBOL_GPL(css_set_lock);
DEFINE_SPINLOCK(trace_cgroup_path_lock);
char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
+bool cgroup_debug __read_mostly;
/*
* Protects cgroup_idr and css_idr so that IDs can be released without
@@ -493,7 +494,7 @@ static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,
}
/**
- * cgroup_e_css - obtain a cgroup's effective css for the specified subsystem
+ * cgroup_e_css_by_mask - obtain a cgroup's effective css for the specified ss
* @cgrp: the cgroup of interest
* @ss: the subsystem of interest (%NULL returns @cgrp->self)
*
@@ -502,8 +503,8 @@ static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,
* enabled. If @ss is associated with the hierarchy @cgrp is on, this
* function is guaranteed to return non-NULL css.
*/
-static struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgrp,
- struct cgroup_subsys *ss)
+static struct cgroup_subsys_state *cgroup_e_css_by_mask(struct cgroup *cgrp,
+ struct cgroup_subsys *ss)
{
lockdep_assert_held(&cgroup_mutex);
@@ -524,6 +525,35 @@ static struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgrp,
}
/**
+ * cgroup_e_css - obtain a cgroup's effective css for the specified subsystem
+ * @cgrp: the cgroup of interest
+ * @ss: the subsystem of interest
+ *
+ * Find and get the effective css of @cgrp for @ss. The effective css is
+ * defined as the matching css of the nearest ancestor including self which
+ * has @ss enabled. If @ss is not mounted on the hierarchy @cgrp is on,
+ * the root css is returned, so this function always returns a valid css.
+ *
+ * The returned css is not guaranteed to be online, and therefore it is the
+ * callers responsiblity to tryget a reference for it.
+ */
+struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgrp,
+ struct cgroup_subsys *ss)
+{
+ struct cgroup_subsys_state *css;
+
+ do {
+ css = cgroup_css(cgrp, ss);
+
+ if (css)
+ return css;
+ cgrp = cgroup_parent(cgrp);
+ } while (cgrp);
+
+ return init_css_set.subsys[ss->id];
+}
+
+/**
* cgroup_get_e_css - get a cgroup's effective css for the specified subsystem
* @cgrp: the cgroup of interest
* @ss: the subsystem of interest
@@ -605,10 +635,11 @@ EXPORT_SYMBOL_GPL(of_css);
*
* Should be called under cgroup_[tree_]mutex.
*/
-#define for_each_e_css(css, ssid, cgrp) \
- for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT; (ssid)++) \
- if (!((css) = cgroup_e_css(cgrp, cgroup_subsys[(ssid)]))) \
- ; \
+#define for_each_e_css(css, ssid, cgrp) \
+ for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT; (ssid)++) \
+ if (!((css) = cgroup_e_css_by_mask(cgrp, \
+ cgroup_subsys[(ssid)]))) \
+ ; \
else
/**
@@ -1007,7 +1038,7 @@ static struct css_set *find_existing_css_set(struct css_set *old_cset,
* @ss is in this hierarchy, so we want the
* effective css from @cgrp.
*/
- template[i] = cgroup_e_css(cgrp, ss);
+ template[i] = cgroup_e_css_by_mask(cgrp, ss);
} else {
/*
* @ss is not in this hierarchy, so we don't want
@@ -1399,12 +1430,15 @@ static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
struct cgroup_subsys *ss = cft->ss;
if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&
- !(cgrp->root->flags & CGRP_ROOT_NOPREFIX))
- snprintf(buf, CGROUP_FILE_NAME_MAX, "%s.%s",
- cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
+ !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {
+ const char *dbg = (cft->flags & CFTYPE_DEBUG) ? ".__DEBUG__." : "";
+
+ snprintf(buf, CGROUP_FILE_NAME_MAX, "%s%s.%s",
+ dbg, cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
cft->name);
- else
+ } else {
strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
+ }
return buf;
}
@@ -1744,7 +1778,7 @@ static int parse_cgroup_root_flags(char *data, unsigned int *root_flags)
*root_flags = 0;
- if (!data)
+ if (!data || *data == '\0')
return 0;
while ((token = strsep(&data, ",")) != NULL) {
@@ -3024,7 +3058,7 @@ static int cgroup_apply_control(struct cgroup *cgrp)
return ret;
/*
- * At this point, cgroup_e_css() results reflect the new csses
+ * At this point, cgroup_e_css_by_mask() results reflect the new csses
* making the following cgroup_update_dfl_csses() properly update
* css associations of all tasks in the subtree.
*/
@@ -3639,7 +3673,8 @@ restart:
continue;
if ((cft->flags & CFTYPE_ONLY_ON_ROOT) && cgroup_parent(cgrp))
continue;
-
+ if ((cft->flags & CFTYPE_DEBUG) && !cgroup_debug)
+ continue;
if (is_add) {
ret = cgroup_add_file(css, cgrp, cft);
if (ret) {
@@ -4202,20 +4237,25 @@ static void css_task_iter_advance(struct css_task_iter *it)
lockdep_assert_held(&css_set_lock);
repeat:
- /*
- * Advance iterator to find next entry. cset->tasks is consumed
- * first and then ->mg_tasks. After ->mg_tasks, we move onto the
- * next cset.
- */
- next = it->task_pos->next;
+ if (it->task_pos) {
+ /*
+ * Advance iterator to find next entry. cset->tasks is
+ * consumed first and then ->mg_tasks. After ->mg_tasks,
+ * we move onto the next cset.
+ */
+ next = it->task_pos->next;
- if (next == it->tasks_head)
- next = it->mg_tasks_head->next;
+ if (next == it->tasks_head)
+ next = it->mg_tasks_head->next;
- if (next == it->mg_tasks_head)
+ if (next == it->mg_tasks_head)
+ css_task_iter_advance_css_set(it);
+ else
+ it->task_pos = next;
+ } else {
+ /* called from start, proceed to the first cset */
css_task_iter_advance_css_set(it);
- else
- it->task_pos = next;
+ }
/* if PROCS, skip over tasks which aren't group leaders */
if ((it->flags & CSS_TASK_ITER_PROCS) && it->task_pos &&
@@ -4255,7 +4295,7 @@ void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
it->cset_head = it->cset_pos;
- css_task_iter_advance_css_set(it);
+ css_task_iter_advance(it);
spin_unlock_irq(&css_set_lock);
}
@@ -5743,6 +5783,16 @@ static int __init cgroup_disable(char *str)
}
__setup("cgroup_disable=", cgroup_disable);
+void __init __weak enable_debug_cgroup(void) { }
+
+static int __init enable_cgroup_debug(char *str)
+{
+ cgroup_debug = true;
+ enable_debug_cgroup();
+ return 1;
+}
+__setup("cgroup_debug", enable_cgroup_debug);
+
/**
* css_tryget_online_from_dir - get corresponding css from a cgroup dentry
* @dentry: directory dentry of interest
@@ -5978,10 +6028,8 @@ static ssize_t show_delegatable_files(struct cftype *files, char *buf,
ret += snprintf(buf + ret, size - ret, "%s\n", cft->name);
- if (unlikely(ret >= size)) {
- WARN_ON(1);
+ if (WARN_ON(ret >= size))
break;
- }
}
return ret;
Powered by cgit, Gruvboxed by Blaster4385.