TononixOS/ubports_kernel_google_msm
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

cgroup: Set CGRP_RELEASABLE when adding to a cgroup

Browse Source 
Changes the meaning of CGRP_RELEASABLE to be set on any cgroup
that has ever had a task or cgroup in it, or had css_get called
on it.  The bit is set in cgroup_attach_task, cgroup_create,
and __css_get.  It is not necessary to set the bit in
cgroup_fork, as the task is either in the root cgroup, in
which can never be released, or the task it was forked from
already set the bit in croup_attach_task.

Signed-off-by: Colin Cross <ccross@android.com>
This commit is contained in:
Colin Cross
2010-11-23 21:37:03 -08:00
parent e5e483d133
commit c0f6fa8c40
2 changed files with 25 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
include/linux/cgroup.h
View File

@@ -84,12 +84,6 @@ enum {
CSS_REMOVED, /* This CSS is dead */
};
/* Caller must verify that the css is not for root cgroup */
static inline void __css_get(struct cgroup_subsys_state *css, int count)
{
atomic_add(count, &css->refcnt);
}
/*
* Call css_get() to hold a reference on the css; it can be used
* for a reference obtained via:
@@ -97,6 +91,7 @@ static inline void __css_get(struct cgroup_subsys_state *css, int count)
* - task->cgroups for a locked task
*/
extern void __css_get(struct cgroup_subsys_state *css, int count);
static inline void css_get(struct cgroup_subsys_state *css)
{
/* We don't need to reference count the root state */
@@ -143,10 +138,7 @@ static inline void css_put(struct cgroup_subsys_state *css)
enum {
/* Control Group is dead */
CGRP_REMOVED,
/*
* Control Group has previously had a child cgroup or a task,
* but no longer (only if CGRP_NOTIFY_ON_RELEASE is set)
*/
/* Control Group has ever had a child cgroup or a task */
CGRP_RELEASABLE,
/* Control Group requires release notifications to userspace */
CGRP_NOTIFY_ON_RELEASE,

53
kernel/cgroup.c
View File

@@ -352,7 +352,15 @@ static struct hlist_head *css_set_hash(struct cgroup_subsys_state *css[])
* compiled into their kernel but not actually in use */
static int use_task_css_set_links __read_mostly;
static void __put_css_set(struct css_set *cg, int taskexit)
/*
* refcounted get/put for css_set objects
*/
static inline void get_css_set(struct css_set *cg)
{
atomic_inc(&cg->refcount);
}
static void put_css_set(struct css_set *cg)
{
struct cg_cgroup_link *link;
struct cg_cgroup_link *saved_link;
@@ -378,12 +386,8 @@ static void __put_css_set(struct css_set *cg, int taskexit)
struct cgroup *cgrp = link->cgrp;
list_del(&link->cg_link_list);
list_del(&link->cgrp_link_list);
if (atomic_dec_and_test(&cgrp->count) &&
notify_on_release(cgrp)) {
if (taskexit)
set_bit(CGRP_RELEASABLE, &cgrp->flags);
if (atomic_dec_and_test(&cgrp->count))
check_for_release(cgrp);
}
kfree(link);
}
@@ -392,24 +396,6 @@ static void __put_css_set(struct css_set *cg, int taskexit)
kfree_rcu(cg, rcu_head);
}
/*
* refcounted get/put for css_set objects
*/
static inline void get_css_set(struct css_set *cg)
{
atomic_inc(&cg->refcount);
}
static inline void put_css_set(struct css_set *cg)
{
__put_css_set(cg, 0);
}
static inline void put_css_set_taskexit(struct css_set *cg)
{
__put_css_set(cg, 1);
}
/*
* compare_css_sets - helper function for find_existing_css_set().
* @cg: candidate css_set being tested
@@ -1931,6 +1917,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
ss->attach(cgrp, &tset);
}
set_bit(CGRP_RELEASABLE, &cgrp->flags);
synchronize_rcu();
/*
@@ -3784,6 +3771,8 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
if (err < 0)
goto err_remove;
set_bit(CGRP_RELEASABLE, &parent->flags);
/* The cgroup directory was pre-locked for us */
BUG_ON(!mutex_is_locked(&cgrp->dentry->d_inode->i_mutex));
@@ -4000,7 +3989,6 @@ again:
cgroup_d_remove_dir(d);
dput(d);
set_bit(CGRP_RELEASABLE, &parent->flags);
check_for_release(parent);
/*
@@ -4631,7 +4619,7 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
task_unlock(tsk);
if (cg)
put_css_set_taskexit(cg);
put_css_set(cg);
}
/**
@@ -4684,6 +4672,14 @@ static void check_for_release(struct cgroup *cgrp)
}
}
/* Caller must verify that the css is not for root cgroup */
void __css_get(struct cgroup_subsys_state *css, int count)
{
atomic_add(count, &css->refcnt);
set_bit(CGRP_RELEASABLE, &css->cgroup->flags);
}
EXPORT_SYMBOL_GPL(__css_get);
/* Caller must verify that the css is not for root cgroup */
void __css_put(struct cgroup_subsys_state *css, int count)
{
@@ -4692,10 +4688,7 @@ void __css_put(struct cgroup_subsys_state *css, int count)
rcu_read_lock();
val = atomic_sub_return(count, &css->refcnt);
if (val == 1) {
if (notify_on_release(cgrp)) {
set_bit(CGRP_RELEASABLE, &cgrp->flags);
check_for_release(cgrp);
}
check_for_release(cgrp);
cgroup_wakeup_rmdir_waiter(cgrp);
}
rcu_read_unlock();