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Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c340
1 files changed, 220 insertions, 120 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2727f9238359..fbc6fc8949b4 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -44,6 +44,7 @@
#include <linux/kmod.h>
#include <linux/delayacct.h>
#include <linux/cgroupstats.h>
+#include <linux/hash.h>
#include <asm/atomic.h>
@@ -118,17 +119,7 @@ static int root_count;
* be called.
*/
static int need_forkexit_callback;
-
-/* bits in struct cgroup flags field */
-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) */
- CGRP_RELEASABLE,
- /* Control Group requires release notifications to userspace */
- CGRP_NOTIFY_ON_RELEASE,
-};
+static int need_mm_owner_callback __read_mostly;
/* convenient tests for these bits */
inline int cgroup_is_removed(const struct cgroup *cgrp)
@@ -204,6 +195,27 @@ static struct cg_cgroup_link init_css_set_link;
static DEFINE_RWLOCK(css_set_lock);
static int css_set_count;
+/* hash table for cgroup groups. This improves the performance to
+ * find an existing css_set */
+#define CSS_SET_HASH_BITS 7
+#define CSS_SET_TABLE_SIZE (1 << CSS_SET_HASH_BITS)
+static struct hlist_head css_set_table[CSS_SET_TABLE_SIZE];
+
+static struct hlist_head *css_set_hash(struct cgroup_subsys_state *css[])
+{
+ int i;
+ int index;
+ unsigned long tmp = 0UL;
+
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++)
+ tmp += (unsigned long)css[i];
+ tmp = (tmp >> 16) ^ tmp;
+
+ index = hash_long(tmp, CSS_SET_HASH_BITS);
+
+ return &css_set_table[index];
+}
+
/* We don't maintain the lists running through each css_set to its
* task until after the first call to cgroup_iter_start(). This
* reduces the fork()/exit() overhead for people who have cgroups
@@ -230,7 +242,7 @@ static int use_task_css_set_links;
static void unlink_css_set(struct css_set *cg)
{
write_lock(&css_set_lock);
- list_del(&cg->list);
+ hlist_del(&cg->hlist);
css_set_count--;
while (!list_empty(&cg->cg_links)) {
struct cg_cgroup_link *link;
@@ -295,9 +307,7 @@ static inline void put_css_set_taskexit(struct css_set *cg)
/*
* find_existing_css_set() is a helper for
* find_css_set(), and checks to see whether an existing
- * css_set is suitable. This currently walks a linked-list for
- * simplicity; a later patch will use a hash table for better
- * performance
+ * css_set is suitable.
*
* oldcg: the cgroup group that we're using before the cgroup
* transition
@@ -314,7 +324,9 @@ static struct css_set *find_existing_css_set(
{
int i;
struct cgroupfs_root *root = cgrp->root;
- struct list_head *l = &init_css_set.list;
+ struct hlist_head *hhead;
+ struct hlist_node *node;
+ struct css_set *cg;
/* Built the set of subsystem state objects that we want to
* see in the new css_set */
@@ -331,18 +343,13 @@ static struct css_set *find_existing_css_set(
}
}
- /* Look through existing cgroup groups to find one to reuse */
- do {
- struct css_set *cg =
- list_entry(l, struct css_set, list);
-
+ hhead = css_set_hash(template);
+ hlist_for_each_entry(cg, node, hhead, hlist) {
if (!memcmp(template, cg->subsys, sizeof(cg->subsys))) {
/* All subsystems matched */
return cg;
}
- /* Try the next cgroup group */
- l = l->next;
- } while (l != &init_css_set.list);
+ }
/* No existing cgroup group matched */
return NULL;
@@ -404,6 +411,8 @@ static struct css_set *find_css_set(
struct list_head tmp_cg_links;
struct cg_cgroup_link *link;
+ struct hlist_head *hhead;
+
/* First see if we already have a cgroup group that matches
* the desired set */
write_lock(&css_set_lock);
@@ -428,6 +437,7 @@ static struct css_set *find_css_set(
kref_init(&res->ref);
INIT_LIST_HEAD(&res->cg_links);
INIT_LIST_HEAD(&res->tasks);
+ INIT_HLIST_NODE(&res->hlist);
/* Copy the set of subsystem state objects generated in
* find_existing_css_set() */
@@ -467,9 +477,12 @@ static struct css_set *find_css_set(
BUG_ON(!list_empty(&tmp_cg_links));
- /* Link this cgroup group into the list */
- list_add(&res->list, &init_css_set.list);
css_set_count++;
+
+ /* Add this cgroup group to the hash table */
+ hhead = css_set_hash(res->subsys);
+ hlist_add_head(&res->hlist, hhead);
+
write_unlock(&css_set_lock);
return res;
@@ -562,7 +575,7 @@ static struct inode_operations cgroup_dir_inode_operations;
static struct file_operations proc_cgroupstats_operations;
static struct backing_dev_info cgroup_backing_dev_info = {
- .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+ .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK,
};
static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb)
@@ -948,7 +961,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
int ret = 0;
struct super_block *sb;
struct cgroupfs_root *root;
- struct list_head tmp_cg_links, *l;
+ struct list_head tmp_cg_links;
INIT_LIST_HEAD(&tmp_cg_links);
/* First find the desired set of subsystems */
@@ -990,6 +1003,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
/* New superblock */
struct cgroup *cgrp = &root->top_cgroup;
struct inode *inode;
+ int i;
BUG_ON(sb->s_root != NULL);
@@ -1034,22 +1048,25 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
/* Link the top cgroup in this hierarchy into all
* the css_set objects */
write_lock(&css_set_lock);
- l = &init_css_set.list;
- do {
+ for (i = 0; i < CSS_SET_TABLE_SIZE; i++) {
+ struct hlist_head *hhead = &css_set_table[i];
+ struct hlist_node *node;
struct css_set *cg;
- struct cg_cgroup_link *link;
- cg = list_entry(l, struct css_set, list);
- BUG_ON(list_empty(&tmp_cg_links));
- link = list_entry(tmp_cg_links.next,
- struct cg_cgroup_link,
- cgrp_link_list);
- list_del(&link->cgrp_link_list);
- link->cg = cg;
- list_add(&link->cgrp_link_list,
- &root->top_cgroup.css_sets);
- list_add(&link->cg_link_list, &cg->cg_links);
- l = l->next;
- } while (l != &init_css_set.list);
+
+ hlist_for_each_entry(cg, node, hhead, hlist) {
+ struct cg_cgroup_link *link;
+
+ BUG_ON(list_empty(&tmp_cg_links));
+ link = list_entry(tmp_cg_links.next,
+ struct cg_cgroup_link,
+ cgrp_link_list);
+ list_del(&link->cgrp_link_list);
+ link->cg = cg;
+ list_add(&link->cgrp_link_list,
+ &root->top_cgroup.css_sets);
+ list_add(&link->cg_link_list, &cg->cg_links);
+ }
+ }
write_unlock(&css_set_lock);
free_cg_links(&tmp_cg_links);
@@ -1307,18 +1324,16 @@ enum cgroup_filetype {
FILE_DIR,
FILE_TASKLIST,
FILE_NOTIFY_ON_RELEASE,
- FILE_RELEASABLE,
FILE_RELEASE_AGENT,
};
-static ssize_t cgroup_write_uint(struct cgroup *cgrp, struct cftype *cft,
- struct file *file,
- const char __user *userbuf,
- size_t nbytes, loff_t *unused_ppos)
+static ssize_t cgroup_write_X64(struct cgroup *cgrp, struct cftype *cft,
+ struct file *file,
+ const char __user *userbuf,
+ size_t nbytes, loff_t *unused_ppos)
{
char buffer[64];
int retval = 0;
- u64 val;
char *end;
if (!nbytes)
@@ -1329,16 +1344,18 @@ static ssize_t cgroup_write_uint(struct cgroup *cgrp, struct cftype *cft,
return -EFAULT;
buffer[nbytes] = 0; /* nul-terminate */
-
- /* strip newline if necessary */
- if (nbytes && (buffer[nbytes-1] == '\n'))
- buffer[nbytes-1] = 0;
- val = simple_strtoull(buffer, &end, 0);
- if (*end)
- return -EINVAL;
-
- /* Pass to subsystem */
- retval = cft->write_uint(cgrp, cft, val);
+ strstrip(buffer);
+ if (cft->write_u64) {
+ u64 val = simple_strtoull(buffer, &end, 0);
+ if (*end)
+ return -EINVAL;
+ retval = cft->write_u64(cgrp, cft, val);
+ } else {
+ s64 val = simple_strtoll(buffer, &end, 0);
+ if (*end)
+ return -EINVAL;
+ retval = cft->write_s64(cgrp, cft, val);
+ }
if (!retval)
retval = nbytes;
return retval;
@@ -1419,23 +1436,39 @@ static ssize_t cgroup_file_write(struct file *file, const char __user *buf,
return -ENODEV;
if (cft->write)
return cft->write(cgrp, cft, file, buf, nbytes, ppos);
- if (cft->write_uint)
- return cgroup_write_uint(cgrp, cft, file, buf, nbytes, ppos);
+ if (cft->write_u64 || cft->write_s64)
+ return cgroup_write_X64(cgrp, cft, file, buf, nbytes, ppos);
+ if (cft->trigger) {
+ int ret = cft->trigger(cgrp, (unsigned int)cft->private);
+ return ret ? ret : nbytes;
+ }
return -EINVAL;
}
-static ssize_t cgroup_read_uint(struct cgroup *cgrp, struct cftype *cft,
- struct file *file,
- char __user *buf, size_t nbytes,
- loff_t *ppos)
+static ssize_t cgroup_read_u64(struct cgroup *cgrp, struct cftype *cft,
+ struct file *file,
+ char __user *buf, size_t nbytes,
+ loff_t *ppos)
{
char tmp[64];
- u64 val = cft->read_uint(cgrp, cft);
+ u64 val = cft->read_u64(cgrp, cft);
int len = sprintf(tmp, "%llu\n", (unsigned long long) val);
return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
}
+static ssize_t cgroup_read_s64(struct cgroup *cgrp, struct cftype *cft,
+ struct file *file,
+ char __user *buf, size_t nbytes,
+ loff_t *ppos)
+{
+ char tmp[64];
+ s64 val = cft->read_s64(cgrp, cft);
+ int len = sprintf(tmp, "%lld\n", (long long) val);
+
+ return simple_read_from_buffer(buf, nbytes, ppos, tmp, len);
+}
+
static ssize_t cgroup_common_file_read(struct cgroup *cgrp,
struct cftype *cft,
struct file *file,
@@ -1490,11 +1523,56 @@ static ssize_t cgroup_file_read(struct file *file, char __user *buf,
if (cft->read)
return cft->read(cgrp, cft, file, buf, nbytes, ppos);
- if (cft->read_uint)
- return cgroup_read_uint(cgrp, cft, file, buf, nbytes, ppos);
+ if (cft->read_u64)
+ return cgroup_read_u64(cgrp, cft, file, buf, nbytes, ppos);
+ if (cft->read_s64)
+ return cgroup_read_s64(cgrp, cft, file, buf, nbytes, ppos);
return -EINVAL;
}
+/*
+ * seqfile ops/methods for returning structured data. Currently just
+ * supports string->u64 maps, but can be extended in future.
+ */
+
+struct cgroup_seqfile_state {
+ struct cftype *cft;
+ struct cgroup *cgroup;
+};
+
+static int cgroup_map_add(struct cgroup_map_cb *cb, const char *key, u64 value)
+{
+ struct seq_file *sf = cb->state;
+ return seq_printf(sf, "%s %llu\n", key, (unsigned long long)value);
+}
+
+static int cgroup_seqfile_show(struct seq_file *m, void *arg)
+{
+ struct cgroup_seqfile_state *state = m->private;
+ struct cftype *cft = state->cft;
+ if (cft->read_map) {
+ struct cgroup_map_cb cb = {
+ .fill = cgroup_map_add,
+ .state = m,
+ };
+ return cft->read_map(state->cgroup, cft, &cb);
+ }
+ return cft->read_seq_string(state->cgroup, cft, m);
+}
+
+int cgroup_seqfile_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+ kfree(seq->private);
+ return single_release(inode, file);
+}
+
+static struct file_operations cgroup_seqfile_operations = {
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = cgroup_seqfile_release,
+};
+
static int cgroup_file_open(struct inode *inode, struct file *file)
{
int err;
@@ -1507,7 +1585,18 @@ static int cgroup_file_open(struct inode *inode, struct file *file)
cft = __d_cft(file->f_dentry);
if (!cft)
return -ENODEV;
- if (cft->open)
+ if (cft->read_map || cft->read_seq_string) {
+ struct cgroup_seqfile_state *state =
+ kzalloc(sizeof(*state), GFP_USER);
+ if (!state)
+ return -ENOMEM;
+ state->cft = cft;
+ state->cgroup = __d_cgrp(file->f_dentry->d_parent);
+ file->f_op = &cgroup_seqfile_operations;
+ err = single_open(file, cgroup_seqfile_show, state);
+ if (err < 0)
+ kfree(state);
+ } else if (cft->open)
err = cft->open(inode, file);
else
err = 0;
@@ -1715,14 +1804,19 @@ static void cgroup_advance_iter(struct cgroup *cgrp,
* The tasklist_lock is not held here, as do_each_thread() and
* while_each_thread() are protected by RCU.
*/
-void cgroup_enable_task_cg_lists(void)
+static void cgroup_enable_task_cg_lists(void)
{
struct task_struct *p, *g;
write_lock(&css_set_lock);
use_task_css_set_links = 1;
do_each_thread(g, p) {
task_lock(p);
- if (list_empty(&p->cg_list))
+ /*
+ * We should check if the process is exiting, otherwise
+ * it will race with cgroup_exit() in that the list
+ * entry won't be deleted though the process has exited.
+ */
+ if (!(p->flags & PF_EXITING) && list_empty(&p->cg_list))
list_add(&p->cg_list, &p->cgroups->tasks);
task_unlock(p);
} while_each_thread(g, p);
@@ -1908,14 +2002,14 @@ int cgroup_scan_tasks(struct cgroup_scanner *scan)
if (heap->size) {
for (i = 0; i < heap->size; i++) {
- struct task_struct *p = heap->ptrs[i];
+ struct task_struct *q = heap->ptrs[i];
if (i == 0) {
- latest_time = p->start_time;
- latest_task = p;
+ latest_time = q->start_time;
+ latest_task = q;
}
/* Process the task per the caller's callback */
- scan->process_task(p, scan);
- put_task_struct(p);
+ scan->process_task(q, scan);
+ put_task_struct(q);
}
/*
* If we had to process any tasks at all, scan again
@@ -2133,11 +2227,6 @@ static u64 cgroup_read_notify_on_release(struct cgroup *cgrp,
return notify_on_release(cgrp);
}
-static u64 cgroup_read_releasable(struct cgroup *cgrp, struct cftype *cft)
-{
- return test_bit(CGRP_RELEASABLE, &cgrp->flags);
-}
-
/*
* for the common functions, 'private' gives the type of file
*/
@@ -2153,16 +2242,10 @@ static struct cftype files[] = {
{
.name = "notify_on_release",
- .read_uint = cgroup_read_notify_on_release,
+ .read_u64 = cgroup_read_notify_on_release,
.write = cgroup_common_file_write,
.private = FILE_NOTIFY_ON_RELEASE,
},
-
- {
- .name = "releasable",
- .read_uint = cgroup_read_releasable,
- .private = FILE_RELEASABLE,
- }
};
static struct cftype cft_release_agent = {
@@ -2396,10 +2479,9 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
return 0;
}
-static void cgroup_init_subsys(struct cgroup_subsys *ss)
+static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
{
struct cgroup_subsys_state *css;
- struct list_head *l;
printk(KERN_INFO "Initializing cgroup subsys %s\n", ss->name);
@@ -2410,34 +2492,19 @@ static void cgroup_init_subsys(struct cgroup_subsys *ss)
BUG_ON(IS_ERR(css));
init_cgroup_css(css, ss, dummytop);
- /* Update all cgroup groups to contain a subsys
+ /* Update the init_css_set to contain a subsys
* pointer to this state - since the subsystem is
- * newly registered, all tasks and hence all cgroup
- * groups are in the subsystem's top cgroup. */
- write_lock(&css_set_lock);
- l = &init_css_set.list;
- do {
- struct css_set *cg =
- list_entry(l, struct css_set, list);
- cg->subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id];
- l = l->next;
- } while (l != &init_css_set.list);
- write_unlock(&css_set_lock);
-
- /* If this subsystem requested that it be notified with fork
- * events, we should send it one now for every process in the
- * system */
- if (ss->fork) {
- struct task_struct *g, *p;
-
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- ss->fork(ss, p);
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
- }
+ * newly registered, all tasks and hence the
+ * init_css_set is in the subsystem's top cgroup. */
+ init_css_set.subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id];
need_forkexit_callback |= ss->fork || ss->exit;
+ need_mm_owner_callback |= !!ss->mm_owner_changed;
+
+ /* At system boot, before all subsystems have been
+ * registered, no tasks have been forked, so we don't
+ * need to invoke fork callbacks here. */
+ BUG_ON(!list_empty(&init_task.tasks));
ss->active = 1;
}
@@ -2453,9 +2520,9 @@ int __init cgroup_init_early(void)
int i;
kref_init(&init_css_set.ref);
kref_get(&init_css_set.ref);
- INIT_LIST_HEAD(&init_css_set.list);
INIT_LIST_HEAD(&init_css_set.cg_links);
INIT_LIST_HEAD(&init_css_set.tasks);
+ INIT_HLIST_NODE(&init_css_set.hlist);
css_set_count = 1;
init_cgroup_root(&rootnode);
list_add(&rootnode.root_list, &roots);
@@ -2468,6 +2535,9 @@ int __init cgroup_init_early(void)
list_add(&init_css_set_link.cg_link_list,
&init_css_set.cg_links);
+ for (i = 0; i < CSS_SET_TABLE_SIZE; i++)
+ INIT_HLIST_HEAD(&css_set_table[i]);
+
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
@@ -2497,7 +2567,7 @@ int __init cgroup_init(void)
{
int err;
int i;
- struct proc_dir_entry *entry;
+ struct hlist_head *hhead;
err = bdi_init(&cgroup_backing_dev_info);
if (err)
@@ -2509,13 +2579,15 @@ int __init cgroup_init(void)
cgroup_init_subsys(ss);
}
+ /* Add init_css_set to the hash table */
+ hhead = css_set_hash(init_css_set.subsys);
+ hlist_add_head(&init_css_set.hlist, hhead);
+
err = register_filesystem(&cgroup_fs_type);
if (err < 0)
goto out;
- entry = create_proc_entry("cgroups", 0, NULL);
- if (entry)
- entry->proc_fops = &proc_cgroupstats_operations;
+ proc_create("cgroups", 0, NULL, &proc_cgroupstats_operations);
out:
if (err)
@@ -2678,6 +2750,34 @@ void cgroup_fork_callbacks(struct task_struct *child)
}
}
+#ifdef CONFIG_MM_OWNER
+/**
+ * cgroup_mm_owner_callbacks - run callbacks when the mm->owner changes
+ * @p: the new owner
+ *
+ * Called on every change to mm->owner. mm_init_owner() does not
+ * invoke this routine, since it assigns the mm->owner the first time
+ * and does not change it.
+ */
+void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new)
+{
+ struct cgroup *oldcgrp, *newcgrp;
+
+ if (need_mm_owner_callback) {
+ int i;
+ for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+ struct cgroup_subsys *ss = subsys[i];
+ oldcgrp = task_cgroup(old, ss->subsys_id);
+ newcgrp = task_cgroup(new, ss->subsys_id);
+ if (oldcgrp == newcgrp)
+ continue;
+ if (ss->mm_owner_changed)
+ ss->mm_owner_changed(ss, oldcgrp, newcgrp);
+ }
+ }
+}
+#endif /* CONFIG_MM_OWNER */
+
/**
* cgroup_post_fork - called on a new task after adding it to the task list
* @child: the task in question
generated by cgit v1.2.3 (git 2.0.4) at 2024-05-28 00:15:24 +0000