[PATCH 3/13] BC: beancounters core and API

[Kirill Korotaev <dev@sw.ru>]

Core functionality and interfaces of BC:
find/create beancounter, initialization,
charge/uncharge of resource, core objects' declarations.

Basic structures:
 bc_resource_parm - resource description
 beancounter      - set of resources, id, lock

Signed-off-by: Pavel Emelianov <xemul@sw.ru>
Signed-off-by: Kirill Korotaev <dev@sw.ru>

---

 include/bc/beancounter.h |  171 +++++++++++++++++++++++++++++++
 include/linux/types.h    |   16 ++
 init/main.c              |    3 
 kernel/bc/beancounter.c  |  253 +++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 443 insertions(+)

--- /dev/null	2006-07-18 14:52:43.075228448 +0400
+++ ./include/bc/beancounter.h	2006-11-03 17:47:18.000000000 +0300
@@ -0,0 +1,171 @@
+/*
+ * include/bc/beancounter.h
+ *
+ * Copyright (C) 2006 OpenVZ SWsoft Inc
+ *
+ */
+
+#ifndef __BEANCOUNTER_H__
+#define __BEANCOUNTER_H__
+
+enum {
+	BC_KMEMSIZE,
+	BC_PRIVVMPAGES,
+	BC_PHYSPAGES,
+	BC_NUMTASKS,
+	BC_NUMFILES,
+
+	BC_RESOURCES
+};
+
+struct bc_resource_parm {
+	unsigned long	barrier;
+	unsigned long	limit;
+	unsigned long	held;
+	unsigned long	minheld;
+	unsigned long	maxheld;
+	unsigned long	failcnt;
+};
+
+#ifdef __KERNEL__
+
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/configfs.h>
+#include <asm/atomic.h>
+
+#define BC_MAXVALUE	((unsigned long)LONG_MAX)
+
+enum bc_severity {
+	BC_BARRIER,
+	BC_LIMIT,
+	BC_FORCE,
+};
+
+struct beancounter;
+
+#ifdef CONFIG_BEANCOUNTERS
+
+struct bc_resource {
+	char	*bcr_name;
+
+	int	(*bcr_init)(struct beancounter *bc, int res);
+	int	(*bcr_change)(struct beancounter *bc,
+			unsigned long new_bar, unsigned long new_lim);
+	void	(*bcr_barrier_hit)(struct beancounter *bc);
+	int	(*bcr_limit_hit)(struct beancounter *bc, unsigned long val,
+			unsigned long flags);
+	void	(*bcr_fini)(struct beancounter *bc);
+};
+
+extern struct bc_resource *bc_resources[];
+
+struct beancounter {
+	atomic_t		bc_refcount;
+	spinlock_t		bc_lock;
+	bcid_t			bc_id;
+	struct hlist_node	bc_hash;
+
+	struct bc_resource_parm bc_parms[BC_RESOURCES];
+};
+
+static inline struct beancounter *bc_get(struct beancounter *bc)
+{
+	atomic_inc(&bc->bc_refcount);
+	return bc;
+}
+
+extern void bc_put(struct beancounter *bc);
+
+#define BC_LOOKUP		0 /* Just lookup in hash
+				   */
+#define BC_ALLOC		1 /* Lookup in hash and try to make
+				   * new BC if no one found
+				   */
+
+extern struct beancounter *bc_findcreate(bcid_t bcid, int bc_flags);
+
+static inline void bc_adjust_maxheld(struct bc_resource_parm *parm)
+{
+	if (parm->maxheld < parm->held)
+		parm->maxheld = parm->held;
+}
+
+static inline void bc_adjust_minheld(struct bc_resource_parm *parm)
+{
+	if (parm->minheld > parm->held)
+		parm->minheld = parm->held;
+}
+
+static inline void bc_init_resource(struct bc_resource_parm *parm,
+		unsigned long bar, unsigned long lim)
+{
+	parm->barrier = bar;
+	parm->limit = lim;
+	parm->held = 0;
+	parm->minheld = 0;
+	parm->maxheld = 0;
+	parm->failcnt = 0;
+}
+
+int bc_change_param(struct beancounter *bc, int res,
+		unsigned long bar, unsigned long lim);
+
+int __must_check bc_charge_locked(struct beancounter *bc, int res_id,
+		unsigned long val, int strict, unsigned long flags);
+static inline int __must_check bc_charge(struct beancounter *bc, int res_id,
+		unsigned long val, int strict)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&bc->bc_lock, flags);
+	ret = bc_charge_locked(bc, res_id, val, strict, flags);
+	spin_unlock_irqrestore(&bc->bc_lock, flags);
+	return ret;
+}
+
+void __must_check bc_uncharge_locked(struct beancounter *bc, int res_id,
+		unsigned long val);
+static inline void bc_uncharge(struct beancounter *bc, int res_id,
+		unsigned long val)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&bc->bc_lock, flags);
+	bc_uncharge_locked(bc, res_id, val);
+	spin_unlock_irqrestore(&bc->bc_lock, flags);
+}
+
+void __init bc_register_resource(int res_id, struct bc_resource *br);
+void __init bc_init_early(void);
+#else /* CONFIG_BEANCOUNTERS */
+static inline int __must_check bc_charge_locked(struct beancounter *bc, int res,
+		unsigned long val, int strict, unsigned long flags)
+{
+	return 0;
+}
+
+static inline int __must_check bc_charge(struct beancounter *bc, int res,
+		unsigned long val, int strict)
+{
+	return 0;
+}
+
+static inline void bc_uncharge_locked(struct beancounter *bc, int res,
+		unsigned long val)
+{
+}
+
+static inline void bc_uncharge(struct beancounter *bc, int res,
+		unsigned long val)
+{
+}
+
+static inline void bc_init_early(void)
+{
+}
+#endif /* CONFIG_BEANCOUNTERS */
+#endif /* __KERNEL__ */
+#endif
--- ./include/linux/types.h.bcprep	2006-11-03 17:46:25.000000000 +0300
+++ ./include/linux/types.h	2006-11-03 17:46:31.000000000 +0300
@@ -40,6 +40,21 @@ typedef __kernel_gid32_t	gid_t;
 typedef __kernel_uid16_t        uid16_t;
 typedef __kernel_gid16_t        gid16_t;
 
+/*
+ * Type of beancounter id (CONFIG_BEANCOUNTERS)
+ * 
+ * The ancient Unix implementations of this kind of resource management and
+ * security are built around setluid() which sets a uid value that cannot
+ * be changed again and is normally used for security purposes. That
+ * happened to be a uid_t and in simple setups at login uid = luid = euid
+ * would be the norm.
+ * 
+ * Thus the Linux one happens to be a uid_t. It could be something else but
+ * for the "container per user" model whatever a container is must be able
+ * to hold all possible uid_t values. Alan Cox.
+ */
+typedef uid_t			bcid_t;
+
 #ifdef CONFIG_UID16
 /* This is defined by include/asm-{arch}/posix_types.h */
 typedef __kernel_old_uid_t	old_uid_t;
@@ -52,6 +67,7 @@ typedef __kernel_old_gid_t	old_gid_t;
 #else
 typedef __kernel_uid_t		uid_t;
 typedef __kernel_gid_t		gid_t;
+typedef __kernel_uid_t		bcid_t;
 #endif /* __KERNEL__ */
 
 #if defined(__GNUC__) && !defined(__STRICT_ANSI__)
--- ./init/main.c.bccore	2006-11-03 17:46:10.000000000 +0300
+++ ./init/main.c	2006-11-03 17:47:18.000000000 +0300
@@ -53,6 +53,8 @@
 #include <linux/lockdep.h>
 #include <linux/pid_namespace.h>
 
+#include <bc/beancounter.h>
+
 #include <asm/io.h>
 #include <asm/bugs.h>
 #include <asm/setup.h>
@@ -483,6 +485,7 @@ asmlinkage void __init start_kernel(void
 	char * command_line;
 	extern struct kernel_param __start___param[], __stop___param[];
 
+	bc_init_early();
 	smp_setup_processor_id();
 
 	/*
--- /dev/null	2006-07-18 14:52:43.075228448 +0400
+++ ./kernel/bc/beancounter.c	2006-11-03 17:47:18.000000000 +0300
@@ -0,0 +1,253 @@
+/*
+ * kernel/bc/beancounter.c
+ *
+ * Copyright (C) 2006 OpenVZ SWsoft Inc
+ *
+ */
+
+#include <linux/sched.h>
+#include <linux/list.h>
+#include <linux/hash.h>
+#include <linux/gfp.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+#include <bc/beancounter.h>
+
+#define BC_HASH_BITS	(8)
+#define BC_HASH_SIZE	(1 << BC_HASH_BITS)
+
+static int bc_dummy_init(struct beancounter *bc, int i)
+{
+	bc_init_resource(&bc->bc_parms[i], BC_MAXVALUE, BC_MAXVALUE);
+	return 0;
+}
+
+static struct bc_resource bc_dummy_res = {
+	.bcr_name = "dummy",
+	.bcr_init = bc_dummy_init,
+};
+
+struct bc_resource *bc_resources[BC_RESOURCES] = {
+	[0 ... BC_RESOURCES - 1] = &bc_dummy_res,
+};
+
+struct beancounter init_bc;
+static struct hlist_head bc_hash[BC_HASH_SIZE];
+static spinlock_t bc_hash_lock;
+static kmem_cache_t *bc_cache;
+
+static void init_beancounter_struct(struct beancounter *bc, bcid_t bcid)
+{
+	bc->bc_id = bcid;
+	spin_lock_init(&bc->bc_lock);
+	atomic_set(&bc->bc_refcount, 1);
+}
+
+struct beancounter *bc_findcreate(bcid_t bcid, int bc_flags)
+{
+	unsigned long flags;
+	struct beancounter *bc;
+	struct beancounter *new_bc;
+	struct hlist_head *head;
+	struct hlist_node *ptr;
+	int i;
+
+	head = &bc_hash[hash_long(bcid, BC_HASH_BITS)];
+	bc = NULL;
+	new_bc = NULL;
+
+retry:
+	spin_lock_irqsave(&bc_hash_lock, flags);
+	hlist_for_each (ptr, head) {
+		bc = hlist_entry(ptr, struct beancounter, bc_hash);
+		if (bc->bc_id == bcid)
+			break;
+	}
+
+	if (bc != NULL) {
+		bc_get(bc);
+		spin_unlock_irqrestore(&bc_hash_lock, flags);
+
+		if (new_bc != NULL)
+			kmem_cache_free(bc_cache, new_bc);
+		return bc;
+	}
+
+	if (new_bc != NULL) {
+		hlist_add_head(&new_bc->bc_hash, head);
+		spin_unlock_irqrestore(&bc_hash_lock, flags);
+		return new_bc;
+	}
+	spin_unlock_irqrestore(&bc_hash_lock, flags);
+
+	if (!(bc_flags & BC_ALLOC))
+		return NULL;
+
+	new_bc = kmem_cache_alloc(bc_cache, GFP_KERNEL);
+	if (new_bc == NULL)
+		return NULL;
+
+	init_beancounter_struct(new_bc, bcid);
+	for (i = 0; i < BC_RESOURCES; i++)
+		if (bc_resources[i]->bcr_init(new_bc, i))
+			goto out_unroll;
+	goto retry;
+
+out_unroll:
+	for (i--; i >= 0; i--)
+		if (bc_resources[i]->bcr_fini)
+			bc_resources[i]->bcr_fini(new_bc);
+	kmem_cache_free(bc_cache, new_bc);
+	return NULL;
+}
+
+void bc_put(struct beancounter *bc)
+{
+	int i;
+	unsigned long flags;
+
+	if (likely(!atomic_dec_and_lock_irqsave(&bc->bc_refcount,
+				&bc_hash_lock, flags)))
+		return;
+
+	hlist_del(&bc->bc_hash);
+	spin_unlock_irqrestore(&bc_hash_lock, flags);
+
+	for (i = 0; i < BC_RESOURCES; i++) {
+		if (bc_resources[i]->bcr_fini)
+			bc_resources[i]->bcr_fini(bc);
+
+		if (bc->bc_parms[i].held != 0)
+			printk(KERN_ERR "BC: Resource %s holds %lu on put\n",
+					bc_resources[i]->bcr_name,
+					bc->bc_parms[i].held);
+	}
+
+	kmem_cache_free(bc_cache, bc);
+}
+
+int bc_charge_locked(struct beancounter *bc, int res, unsigned long val,
+		int strict, unsigned long flags)
+{
+	struct bc_resource_parm *parm;
+	unsigned long new_held;
+
+	BUG_ON(val > BC_MAXVALUE);
+
+	parm = &bc->bc_parms[res];
+	new_held = parm->held + val;
+
+	switch (strict) {
+	case BC_LIMIT:
+		if (new_held > parm->limit)
+			break;
+		/* fallthrough */
+	case BC_BARRIER:
+		if (new_held > parm->barrier) {
+			if (strict == BC_BARRIER)
+				break;
+			if (parm->held < parm->barrier &&
+					bc_resources[res]->bcr_barrier_hit)
+				bc_resources[res]->bcr_barrier_hit(bc);
+		}
+		/* fallthrough */
+	case BC_FORCE:
+		parm->held = new_held;
+		bc_adjust_maxheld(parm);
+		return 0;
+	default:
+		BUG();
+	}
+
+	if (bc_resources[res]->bcr_limit_hit)
+		return bc_resources[res]->bcr_limit_hit(bc, val, flags);
+
+	parm->failcnt++;
+	return -ENOMEM;
+}
+
+void bc_uncharge_locked(struct beancounter *bc, int res, unsigned long val)
+{
+	struct bc_resource_parm *parm;
+
+	BUG_ON(val > BC_MAXVALUE);
+
+	parm = &bc->bc_parms[res];
+	if (unlikely(val > parm->held)) {
+		printk(KERN_ERR "BC: Uncharging too much of %s: %lu vs %lu\n",
+				bc_resources[res]->bcr_name,
+				val, parm->held);
+		val = parm->held;
+	}
+
+	parm->held -= val;
+	bc_adjust_minheld(parm);
+}
+
+int bc_change_param(struct beancounter *bc, int res,
+		unsigned long bar, unsigned long lim)
+{
+	int ret;
+
+	ret = -EINVAL;
+	if (bar > lim)
+		goto out;
+	if (bar > BC_MAXVALUE || lim > BC_MAXVALUE)
+		goto out;
+
+	ret = 0;
+	spin_lock_irq(&bc->bc_lock);
+	if (bc_resources[res]->bcr_change) {
+		ret = bc_resources[res]->bcr_change(bc, bar, lim);
+		if (ret < 0)
+			goto out_unlock;
+	}
+
+	bc->bc_parms[res].barrier = bar;
+	bc->bc_parms[res].limit = lim;
+
+out_unlock:
+	spin_unlock_irq(&bc->bc_lock);
+out:
+	return ret;
+}
+
+void __init bc_register_resource(int res_id, struct bc_resource *br)
+{
+	BUG_ON(bc_resources[res_id] != &bc_dummy_res);
+	BUG_ON(res_id >= BC_RESOURCES);
+
+	bc_resources[res_id] = br;
+}
+
+void __init bc_init_early(void)
+{
+	int i;
+
+	init_beancounter_struct(&init_bc, 0);
+
+	for (i = 0; i < BC_RESOURCES; i++) {
+		init_bc.bc_parms[i].barrier = BC_MAXVALUE;
+		init_bc.bc_parms[i].limit = BC_MAXVALUE;
+	}
+
+	spin_lock_init(&bc_hash_lock);
+	hlist_add_head(&init_bc.bc_hash, &bc_hash[hash_long(0, BC_HASH_BITS)]);
+}
+
+int __init bc_init_late(void)
+{
+	bc_cache = kmem_cache_create("beancounters",
+			sizeof(struct beancounter), 0,
+			SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL, NULL);
+	return 0;
+}
+
+__initcall(bc_init_late);
+
+EXPORT_SYMBOL(bc_resources);
+EXPORT_SYMBOL(init_bc);
+EXPORT_SYMBOL(bc_change_param);
+EXPORT_SYMBOL(bc_findcreate);
+EXPORT_SYMBOL(bc_put);