1 files changed, 214 insertions, 119 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 6d8de051382..fbc6fc8949b 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;
@@ -1715,7 +1804,7 @@ 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);
@@ -1913,14 +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
@@ -2138,11 +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
  */
@@ -2158,16 +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 = {
@@ -2401,10 +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);
 
@@ -2415,34 +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;
 }
@@ -2458,9 +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);
@@ -2473,6 +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];
 
@@ -2502,7 +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)
@@ -2514,13 +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)
@@ -2683,6 +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