---
include/linux/cgroup-defs.h | 2 ++
include/linux/cgroup.h | 32 ++++++++++++++++++++++++--------
kernel/cgroup/cgroup-internal.h | 1 +
kernel/cgroup/cgroup-v1.c | 6 ++++--
kernel/cgroup/cgroup.c | 26 ++++++++++++++++++++++----
5 files changed, 53 insertions(+), 14 deletions(-)
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index f5da2396a809..34a284ef3a78 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -166,6 +166,8 @@ struct cgroup_subsys_state {
* fields of the containing structure.
*/
struct cgroup_subsys_state *parent;
+
+ bool debug;
};
/*
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 5708ad663572..72c076920072 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -295,6 +295,8 @@ void css_task_iter_end(struct css_task_iter *it);
* Inline functions.
*/
+extern void css_refcount(struct cgroup_subsys_state *css, const char *op);
+
/**
* css_get - obtain a reference on the specified css
* @css: target css
@@ -303,8 +305,10 @@ void css_task_iter_end(struct css_task_iter *it);
*/
static inline void css_get(struct cgroup_subsys_state *css)
{
- if (!(css->flags & CSS_NO_REF))
+ if (!(css->flags & CSS_NO_REF)) {
percpu_ref_get(&css->refcnt);
+ css_refcount(css, "GET");
+ }
}
/**
@@ -316,8 +320,10 @@ static inline void css_get(struct cgroup_subsys_state *css)
*/
static inline void css_get_many(struct cgroup_subsys_state *css, unsigned int n)
{
- if (!(css->flags & CSS_NO_REF))
+ if (!(css->flags & CSS_NO_REF)) {
percpu_ref_get_many(&css->refcnt, n);
+ css_refcount(css, "GETM");
+ }
}
/**
@@ -335,8 +341,11 @@ static inline bool css_tryget(struct cgroup_subsys_state *css)
{
if (css->flags & CSS_CREATING)
return false;
- if (!(css->flags & CSS_NO_REF))
- return percpu_ref_tryget(&css->refcnt);
+ if (css->flags & CSS_NO_REF)
+ return true;
+ if (!percpu_ref_tryget(&css->refcnt))
+ return false;
+ css_refcount(css, "TRY");
return true;
}
@@ -354,8 +363,11 @@ static inline bool css_tryget_online(struct cgroup_subsys_state *css)
{
if (css->flags & CSS_CREATING)
return false;
- if (!(css->flags & CSS_NO_REF))
- return percpu_ref_tryget_live(&css->refcnt);
+ if (css->flags & CSS_NO_REF)
+ return true;
+ if (!percpu_ref_tryget_live(&css->refcnt))
+ return false;
+ css_refcount(css, "TRYO");
return true;
}
@@ -387,8 +399,10 @@ static inline bool css_is_dying(struct cgroup_subsys_state *css)
*/
static inline void css_put(struct cgroup_subsys_state *css)
{
- if (!(css->flags & CSS_NO_REF))
+ if (!(css->flags & CSS_NO_REF)) {
percpu_ref_put(&css->refcnt);
+ css_refcount(css, "PUT");
+ }
}
/**
@@ -400,8 +414,10 @@ static inline void css_put(struct cgroup_subsys_state *css)
*/
static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
{
- if (!(css->flags & CSS_NO_REF))
+ if (!(css->flags & CSS_NO_REF)) {
percpu_ref_put_many(&css->refcnt, n);
+ css_refcount(css, "PUTM");
+ }
}
static inline void cgroup_get(struct cgroup *cgrp)
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index b22c3d95d8eb..afe417c44602 100644
--- a/kernel/cgroup/cgroup-internal.h
+++ b/kernel/cgroup/cgroup-internal.h
@@ -46,6 +46,7 @@ struct cgroup_fs_context {
unsigned int flags; /* CGRP_ROOT_* flags */
/* cgroup1 bits */
+ bool debug;
bool is_new_root; /* ->root is new and needs refcnt init */
bool cpuset_clone_children;
bool none; /* User explicitly requested empty subsystem */
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 0fbbde86a64d..281930390c6f 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -1033,6 +1033,8 @@ int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param)
return cg_invalf(fc, "cgroup1: name respecified");
ctx->name = param->string;
param->string = NULL;
+ if (strcmp(ctx->name, "xxxxy") == 0)
+ ctx->debug = true;
return 0;
}
@@ -1174,7 +1176,7 @@ int cgroup1_get_tree(struct fs_context *fc)
ss->root == &cgrp_dfl_root)
continue;
- if (!percpu_ref_tryget_live(&ss->root->cgrp.self.refcnt)) {
+ if (!css_tryget_online(&ss->root->cgrp.self)) {
mutex_unlock(&cgroup_mutex);
goto err_restart;
}
@@ -1227,7 +1229,7 @@ int cgroup1_get_tree(struct fs_context *fc)
*/
pinned_sb = kernfs_pin_sb(root->kf_root, NULL);
if (IS_ERR(pinned_sb) ||
- !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) {
+ !css_tryget_online(&root->cgrp.self)) {
mutex_unlock(&cgroup_mutex);
if (!IS_ERR_OR_NULL(pinned_sb))
deactivate_super(pinned_sb);
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 091e7eca3661..a25c6dee8515 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1907,6 +1907,8 @@ void init_cgroup_root(struct cgroup_fs_context *ctx)
strscpy(root->name, ctx->name, MAX_CGROUP_ROOT_NAMELEN);
if (ctx->cpuset_clone_children)
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
+ if (ctx->debug)
+ cgrp->self.debug = true;
}
int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
@@ -1926,7 +1928,7 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
root_cgrp->ancestor_ids[0] = ret;
ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release,
- 0, GFP_KERNEL);
+ PERCPU_REF_INIT_ATOMIC, GFP_KERNEL);
if (ret)
goto out;
@@ -2025,6 +2027,8 @@ int cgroup_do_get_tree(struct fs_context *fc)
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
int ret;
+ printk("*** cgroup_do_get_tree()\n");
+
ctx->kfc.root = ctx->root->kf_root;
ctx->kfc.fill_super = cgroup_fill_super;
@@ -2072,6 +2076,8 @@ static int cgroup_get_tree(struct fs_context *fc)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+ printk("*** cgroup_get_tree()\n");
+
/*
* The first time anyone tries to mount a cgroup, enable the list
* linking each css_set to its tasks and fix up all existing tasks.
@@ -2169,8 +2175,10 @@ static void cgroup_kill_sb(struct super_block *sb)
if (!list_empty(&root->cgrp.self.children) ||
root == &cgrp_dfl_root)
cgroup_put(&root->cgrp);
- else
+ else {
+ css_refcount(&root->cgrp.self, "KIL");
percpu_ref_kill(&root->cgrp.self.refcnt);
+ }
kernfs_kill_sb(sb);
}
@@ -4894,7 +4902,7 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
init_and_link_css(css, ss, cgrp);
- err = percpu_ref_init(&css->refcnt, css_release, 0, GFP_KERNEL);
+ err = percpu_ref_init(&css->refcnt, css_release, PERCPU_REF_INIT_ATOMIC, GFP_KERNEL);
if (err)
goto err_free_css;
@@ -4949,7 +4957,7 @@ static struct cgroup *cgroup_create(struct cgroup *parent)
if (!cgrp)
return ERR_PTR(-ENOMEM);
- ret = percpu_ref_init(&cgrp->self.refcnt, css_release, 0, GFP_KERNEL);
+ ret = percpu_ref_init(&cgrp->self.refcnt, css_release, PERCPU_REF_INIT_ATOMIC, GFP_KERNEL);
if (ret)
goto out_free_cgrp;
@@ -5197,6 +5205,7 @@ static void kill_css(struct cgroup_subsys_state *css)
* Use percpu_ref_kill_and_confirm() to get notifications as each
* css is confirmed to be seen as killed on all CPUs.
*/
+ css_refcount(css, "KLC");
percpu_ref_kill_and_confirm(&css->refcnt, css_killed_ref_fn);
}
@@ -5281,6 +5290,7 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
cgroup1_check_for_release(parent);
/* put the base reference */
+ css_refcount(&cgrp->self, "KIL");
percpu_ref_kill(&cgrp->self.refcnt);
return 0;
@@ -6109,3 +6119,11 @@ static int __init cgroup_sysfs_init(void)
}
subsys_initcall(cgroup_sysfs_init);
#endif /* CONFIG_SYSFS */
+
+noinline void css_refcount(struct cgroup_subsys_state *css, const char *op)
+{
+ if (css->debug)
+ printk("*** %p %s %2ld: %pSR\n",
+ css, op, atomic_long_read(&css->refcnt.count),
+ __builtin_return_address(0));
+}
