[linux-block.git] / fs / ext4 / mballoc.h

/*
 *  fs/ext4/mballoc.h
 *
 *  Written by: Alex Tomas <alex@clusterfs.com>
 *
 */
#ifndef _EXT4_MBALLOC_H
#define _EXT4_MBALLOC_H

#include <linux/time.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>
#include <linux/module.h>
#include <linux/swap.h>
#include <linux/proc_fs.h>
#include <linux/pagemap.h>
#include <linux/seq_file.h>
#include <linux/version.h>
#include <linux/blkdev.h>
#include <linux/marker.h>
#include <linux/mutex.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "group.h"

/*
 * with AGGRESSIVE_CHECK allocator runs consistency checks over
 * structures. these checks slow things down a lot
 */
#define AGGRESSIVE_CHECK__

/*
 * with DOUBLE_CHECK defined mballoc creates persistent in-core
 * bitmaps, maintains and uses them to check for double allocations
 */
#define DOUBLE_CHECK__

/*
 */
#define MB_DEBUG__
#ifdef MB_DEBUG
#define mb_debug(fmt, a...)	printk(fmt, ##a)
#else
#define mb_debug(fmt, a...)
#endif

/*
 * with EXT4_MB_HISTORY mballoc stores last N allocations in memory
 * and you can monitor it in /proc/fs/ext4/<dev>/mb_history
 */
#define EXT4_MB_HISTORY
#define EXT4_MB_HISTORY_ALLOC		1	/* allocation */
#define EXT4_MB_HISTORY_PREALLOC	2	/* preallocated blocks used */
#define EXT4_MB_HISTORY_DISCARD		4	/* preallocation discarded */
#define EXT4_MB_HISTORY_FREE		8	/* free */

#define EXT4_MB_HISTORY_DEFAULT		(EXT4_MB_HISTORY_ALLOC | \
					 EXT4_MB_HISTORY_PREALLOC)

/*
 * How long mballoc can look for a best extent (in found extents)
 */
#define MB_DEFAULT_MAX_TO_SCAN		200

/*
 * How long mballoc must look for a best extent
 */
#define MB_DEFAULT_MIN_TO_SCAN		10

/*
 * How many groups mballoc will scan looking for the best chunk
 */
#define MB_DEFAULT_MAX_GROUPS_TO_SCAN	5

/*
 * with 'ext4_mb_stats' allocator will collect stats that will be
 * shown at umount. The collecting costs though!
 */
#define MB_DEFAULT_STATS		1

/*
 * files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
 * by the stream allocator, which purpose is to pack requests
 * as close each to other as possible to produce smooth I/O traffic
 * We use locality group prealloc space for stream request.
 * We can tune the same via /proc/fs/ext4/<parition>/stream_req
 */
#define MB_DEFAULT_STREAM_THRESHOLD	16	/* 64K */

/*
 * for which requests use 2^N search using buddies
 */
#define MB_DEFAULT_ORDER2_REQS		2

/*
 * default group prealloc size 512 blocks
 */
#define MB_DEFAULT_GROUP_PREALLOC	512

static struct kmem_cache *ext4_pspace_cachep;
static struct kmem_cache *ext4_ac_cachep;
static struct kmem_cache *ext4_free_ext_cachep;

struct ext4_free_data {
	/* this links the free block information from group_info */
	struct rb_node node;

	/* this links the free block information from ext4_sb_info */
	struct list_head list;

	/* group which free block extent belongs */
	ext4_group_t group;

	/* free block extent */
	ext4_grpblk_t start_blk;
	ext4_grpblk_t count;

	/* transaction which freed this extent */
	tid_t	t_tid;
};

struct ext4_group_info {
	unsigned long	bb_state;
	struct rb_root  bb_free_root;
	unsigned short	bb_first_free;
	unsigned short	bb_free;
	unsigned short	bb_fragments;
	struct		list_head bb_prealloc_list;
#ifdef DOUBLE_CHECK
	void		*bb_bitmap;
#endif
	struct rw_semaphore alloc_sem;
	unsigned short	bb_counters[];
};

#define EXT4_GROUP_INFO_NEED_INIT_BIT	0
#define EXT4_GROUP_INFO_LOCKED_BIT	1

#define EXT4_MB_GRP_NEED_INIT(grp)	\
	(test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))


struct ext4_prealloc_space {
	struct list_head	pa_inode_list;
	struct list_head	pa_group_list;
	union {
		struct list_head pa_tmp_list;
		struct rcu_head	pa_rcu;
	} u;
	spinlock_t		pa_lock;
	atomic_t		pa_count;
	unsigned		pa_deleted;
	ext4_fsblk_t		pa_pstart;	/* phys. block */
	ext4_lblk_t		pa_lstart;	/* log. block */
	unsigned short		pa_len;		/* len of preallocated chunk */
	unsigned short		pa_free;	/* how many blocks are free */
	unsigned short		pa_linear;	/* consumed in one direction
						 * strictly, for grp prealloc */
	spinlock_t		*pa_obj_lock;
	struct inode		*pa_inode;	/* hack, for history only */
};


struct ext4_free_extent {
	ext4_lblk_t fe_logical;
	ext4_grpblk_t fe_start;
	ext4_group_t fe_group;
	int fe_len;
};

/*
 * Locality group:
 *   we try to group all related changes together
 *   so that writeback can flush/allocate them together as well
 *   Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
 *   (512). We store prealloc space into the hash based on the pa_free blocks
 *   order value.ie, fls(pa_free)-1;
 */
#define PREALLOC_TB_SIZE 10
struct ext4_locality_group {
	/* for allocator */
	/* to serialize allocates */
	struct mutex		lg_mutex;
	/* list of preallocations */
	struct list_head	lg_prealloc_list[PREALLOC_TB_SIZE];
	spinlock_t		lg_prealloc_lock;
};

struct ext4_allocation_context {
	struct inode *ac_inode;
	struct super_block *ac_sb;

	/* original request */
	struct ext4_free_extent ac_o_ex;

	/* goal request (after normalization) */
	struct ext4_free_extent ac_g_ex;

	/* the best found extent */
	struct ext4_free_extent ac_b_ex;

	/* copy of the bext found extent taken before preallocation efforts */
	struct ext4_free_extent ac_f_ex;

	/* number of iterations done. we have to track to limit searching */
	unsigned long ac_ex_scanned;
	__u16 ac_groups_scanned;
	__u16 ac_found;
	__u16 ac_tail;
	__u16 ac_buddy;
	__u16 ac_flags;		/* allocation hints */
	__u8 ac_status;
	__u8 ac_criteria;
	__u8 ac_repeats;
	__u8 ac_2order;		/* if request is to allocate 2^N blocks and
				 * N > 0, the field stores N, otherwise 0 */
	__u8 ac_op;		/* operation, for history only */
	struct page *ac_bitmap_page;
	struct page *ac_buddy_page;
	struct ext4_prealloc_space *ac_pa;
	struct ext4_locality_group *ac_lg;
};

#define AC_STATUS_CONTINUE	1
#define AC_STATUS_FOUND		2
#define AC_STATUS_BREAK		3

struct ext4_mb_history {
	struct ext4_free_extent orig;	/* orig allocation */
	struct ext4_free_extent goal;	/* goal allocation */
	struct ext4_free_extent result;	/* result allocation */
	unsigned pid;
	unsigned ino;
	__u16 found;	/* how many extents have been found */
	__u16 groups;	/* how many groups have been scanned */
	__u16 tail;	/* what tail broke some buddy */
	__u16 buddy;	/* buddy the tail ^^^ broke */
	__u16 flags;
	__u8 cr:3;	/* which phase the result extent was found at */
	__u8 op:4;
	__u8 merged:1;
};

struct ext4_buddy {
	struct page *bd_buddy_page;
	void *bd_buddy;
	struct page *bd_bitmap_page;
	void *bd_bitmap;
	struct ext4_group_info *bd_info;
	struct super_block *bd_sb;
	__u16 bd_blkbits;
	ext4_group_t bd_group;
	struct rw_semaphore *alloc_semp;
};
#define EXT4_MB_BITMAP(e4b)	((e4b)->bd_bitmap)
#define EXT4_MB_BUDDY(e4b)	((e4b)->bd_buddy)

#ifndef EXT4_MB_HISTORY
static inline void ext4_mb_store_history(struct ext4_allocation_context *ac)
{
	return;
}
#else
static void ext4_mb_store_history(struct ext4_allocation_context *ac);
#endif

#define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)

struct buffer_head *read_block_bitmap(struct super_block *, ext4_group_t);

static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
					ext4_group_t group);
static void ext4_mb_return_to_preallocation(struct inode *inode,
					struct ext4_buddy *e4b, sector_t block,
					int count);
static void ext4_mb_put_pa(struct ext4_allocation_context *,
			struct super_block *, struct ext4_prealloc_space *pa);
static int ext4_mb_init_per_dev_proc(struct super_block *sb);
static int ext4_mb_destroy_per_dev_proc(struct super_block *sb);
static void release_blocks_on_commit(journal_t *journal, transaction_t *txn);


static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group)
{
	struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);

	bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
}

static inline void ext4_unlock_group(struct super_block *sb,
					ext4_group_t group)
{
	struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);

	bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
}

static inline int ext4_is_group_locked(struct super_block *sb,
					ext4_group_t group)
{
	struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);

	return bit_spin_is_locked(EXT4_GROUP_INFO_LOCKED_BIT,
						&(grinfo->bb_state));
}

static ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
					struct ext4_free_extent *fex)
{
	ext4_fsblk_t block;

	block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb)
			+ fex->fe_start
			+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
	return block;
}
#endif
Commit	Line	Data
8f6e39a7 MC	1	/*
	2	* fs/ext4/mballoc.h
	3	*
	4	* Written by: Alex Tomas <alex@clusterfs.com>
	5	*
	6	*/
	7	#ifndef _EXT4_MBALLOC_H
	8	#define _EXT4_MBALLOC_H
	9
	10	#include <linux/time.h>
	11	#include <linux/fs.h>
	12	#include <linux/namei.h>
	13	#include <linux/quotaops.h>
	14	#include <linux/buffer_head.h>
	15	#include <linux/module.h>
	16	#include <linux/swap.h>
	17	#include <linux/proc_fs.h>
	18	#include <linux/pagemap.h>
	19	#include <linux/seq_file.h>
	20	#include <linux/version.h>
8a0aba73 TT	21	#include <linux/blkdev.h>
8a0aba73 TT	22	#include <linux/marker.h>
920313a7	23	#include <linux/mutex.h>
8f6e39a7 MC	24	#include "ext4_jbd2.h"
	25	#include "ext4.h"
	26	#include "group.h"
	27
	28	/*
	29	* with AGGRESSIVE_CHECK allocator runs consistency checks over
	30	* structures. these checks slow things down a lot
	31	*/
	32	#define AGGRESSIVE_CHECK__
	33
	34	/*
	35	* with DOUBLE_CHECK defined mballoc creates persistent in-core
	36	* bitmaps, maintains and uses them to check for double allocations
	37	*/
	38	#define DOUBLE_CHECK__
	39
	40	/*
	41	*/
	42	#define MB_DEBUG__
	43	#ifdef MB_DEBUG
	44	#define mb_debug(fmt, a...) printk(fmt, ##a)
	45	#else
	46	#define mb_debug(fmt, a...)
	47	#endif
	48
	49	/*
	50	* with EXT4_MB_HISTORY mballoc stores last N allocations in memory
	51	* and you can monitor it in /proc/fs/ext4/<dev>/mb_history
	52	*/
	53	#define EXT4_MB_HISTORY
	54	#define EXT4_MB_HISTORY_ALLOC 1 /* allocation */
	55	#define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */
	56	#define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */
	57	#define EXT4_MB_HISTORY_FREE 8 /* free */
	58
	59	#define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC \| \
	60	EXT4_MB_HISTORY_PREALLOC)
	61
	62	/*
	63	* How long mballoc can look for a best extent (in found extents)
	64	*/
	65	#define MB_DEFAULT_MAX_TO_SCAN 200
	66
	67	/*
	68	* How long mballoc must look for a best extent
	69	*/
	70	#define MB_DEFAULT_MIN_TO_SCAN 10
	71
	72	/*
	73	* How many groups mballoc will scan looking for the best chunk
	74	*/
	75	#define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5
	76
	77	/*
	78	* with 'ext4_mb_stats' allocator will collect stats that will be
	79	* shown at umount. The collecting costs though!
	80	*/
	81	#define MB_DEFAULT_STATS 1
	82
	83	/*
	84	* files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
	85	* by the stream allocator, which purpose is to pack requests
	86	* as close each to other as possible to produce smooth I/O traffic
	87	* We use locality group prealloc space for stream request.
88	* We can tune the same via /proc/fs/ext4/<parition>/stream_req
89	*/
90	#define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */
91
92	/*
93	* for which requests use 2^N search using buddies
94	*/
95	#define MB_DEFAULT_ORDER2_REQS 2
96
97	/*
98	* default group prealloc size 512 blocks
99	*/
100	#define MB_DEFAULT_GROUP_PREALLOC 512
101
102	static struct kmem_cache *ext4_pspace_cachep;
103	static struct kmem_cache *ext4_ac_cachep;
c894058d	104	static struct kmem_cache *ext4_free_ext_cachep;
8f6e39a7	105
c894058d AK	106	struct ext4_free_data {
	107	/* this links the free block information from group_info */
	108	struct rb_node node;
8f6e39a7	109
c894058d	110	/* this links the free block information from ext4_sb_info */
8f6e39a7	111	struct list_head list;
c894058d AK	112
	113	/* group which free block extent belongs */
	114	ext4_group_t group;
	115
	116	/* free block extent */
	117	ext4_grpblk_t start_blk;
	118	ext4_grpblk_t count;
	119
	120	/* transaction which freed this extent */
	121	tid_t t_tid;
8f6e39a7 MC	122	};
	123
	124	struct ext4_group_info {
	125	unsigned long bb_state;
c894058d	126	struct rb_root bb_free_root;
8f6e39a7 MC	127	unsigned short bb_first_free;
	128	unsigned short bb_free;
	129	unsigned short bb_fragments;
	130	struct list_head bb_prealloc_list;
	131	#ifdef DOUBLE_CHECK
	132	void *bb_bitmap;
	133	#endif
920313a7	134	struct rw_semaphore alloc_sem;
8f6e39a7 MC	135	unsigned short bb_counters[];
	136	};
	137
	138	#define EXT4_GROUP_INFO_NEED_INIT_BIT 0
	139	#define EXT4_GROUP_INFO_LOCKED_BIT 1
	140
	141	#define EXT4_MB_GRP_NEED_INIT(grp) \
	142	(test_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &((grp)->bb_state)))
	143
	144
	145	struct ext4_prealloc_space {
	146	struct list_head pa_inode_list;
	147	struct list_head pa_group_list;
	148	union {
	149	struct list_head pa_tmp_list;
	150	struct rcu_head pa_rcu;
	151	} u;
	152	spinlock_t pa_lock;
	153	atomic_t pa_count;
	154	unsigned pa_deleted;
	155	ext4_fsblk_t pa_pstart; /* phys. block */
	156	ext4_lblk_t pa_lstart; /* log. block */
	157	unsigned short pa_len; /* len of preallocated chunk */
	158	unsigned short pa_free; /* how many blocks are free */
	159	unsigned short pa_linear; /* consumed in one direction
	160	* strictly, for grp prealloc */
	161	spinlock_t *pa_obj_lock;
	162	struct inode pa_inode; / hack, for history only */
	163	};
	164
	165
	166	struct ext4_free_extent {
	167	ext4_lblk_t fe_logical;
	168	ext4_grpblk_t fe_start;
	169	ext4_group_t fe_group;
	170	int fe_len;
	171	};
	172
	173	/*
	174	* Locality group:
	175	* we try to group all related changes together
	176	* so that writeback can flush/allocate them together as well
6be2ded1 AK	177	* Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
	178	* (512). We store prealloc space into the hash based on the pa_free blocks
	179	* order value.ie, fls(pa_free)-1;
8f6e39a7	180	*/
6be2ded1	181	#define PREALLOC_TB_SIZE 10
8f6e39a7 MC	182	struct ext4_locality_group {
8f6e39a7 MC	183	/* for allocator */
6be2ded1 AK	184	/* to serialize allocates */
	185	struct mutex lg_mutex;
	186	/* list of preallocations */
	187	struct list_head lg_prealloc_list[PREALLOC_TB_SIZE];
8f6e39a7 MC	188	spinlock_t lg_prealloc_lock;
	189	};
	190
	191	struct ext4_allocation_context {
	192	struct inode *ac_inode;
	193	struct super_block *ac_sb;
	194
	195	/* original request */
	196	struct ext4_free_extent ac_o_ex;
	197
	198	/* goal request (after normalization) */
	199	struct ext4_free_extent ac_g_ex;
	200
	201	/* the best found extent */
	202	struct ext4_free_extent ac_b_ex;
	203
	204	/* copy of the bext found extent taken before preallocation efforts */
	205	struct ext4_free_extent ac_f_ex;
	206
	207	/* number of iterations done. we have to track to limit searching */
	208	unsigned long ac_ex_scanned;
	209	__u16 ac_groups_scanned;
	210	__u16 ac_found;
	211	__u16 ac_tail;
	212	__u16 ac_buddy;
	213	__u16 ac_flags; /* allocation hints */
	214	__u8 ac_status;
	215	__u8 ac_criteria;
	216	__u8 ac_repeats;
	217	__u8 ac_2order; /* if request is to allocate 2^N blocks and
	218	* N > 0, the field stores N, otherwise 0 */
	219	__u8 ac_op; /* operation, for history only */
	220	struct page *ac_bitmap_page;
	221	struct page *ac_buddy_page;
	222	struct ext4_prealloc_space *ac_pa;
	223	struct ext4_locality_group *ac_lg;
	224	};
	225
	226	#define AC_STATUS_CONTINUE 1
	227	#define AC_STATUS_FOUND 2
	228	#define AC_STATUS_BREAK 3
	229
	230	struct ext4_mb_history {
	231	struct ext4_free_extent orig; /* orig allocation */
	232	struct ext4_free_extent goal; /* goal allocation */
	233	struct ext4_free_extent result; /* result allocation */
	234	unsigned pid;
	235	unsigned ino;
	236	__u16 found; /* how many extents have been found */
	237	__u16 groups; /* how many groups have been scanned */
	238	__u16 tail; /* what tail broke some buddy */
	239	__u16 buddy; /* buddy the tail ^^^ broke */
	240	__u16 flags;
	241	__u8 cr:3; /* which phase the result extent was found at */
	242	__u8 op:4;
	243	__u8 merged:1;
	244	};
	245
	246	struct ext4_buddy {
	247	struct page *bd_buddy_page;
	248	void *bd_buddy;
	249	struct page *bd_bitmap_page;
	250	void *bd_bitmap;
	251	struct ext4_group_info *bd_info;
252	struct super_block *bd_sb;
253	__u16 bd_blkbits;
254	ext4_group_t bd_group;
920313a7	255	struct rw_semaphore *alloc_semp;
8f6e39a7 MC	256	};
	257	#define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap)
	258	#define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy)
	259
	260	#ifndef EXT4_MB_HISTORY
	261	static inline void ext4_mb_store_history(struct ext4_allocation_context *ac)
	262	{
	263	return;
	264	}
	265	#else
	266	static void ext4_mb_store_history(struct ext4_allocation_context *ac);
	267	#endif
	268
	269	#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
	270
8f6e39a7 MC	271	struct buffer_head read_block_bitmap(struct super_block , ext4_group_t);
	272
	273	static void ext4_mb_generate_from_pa(struct super_block sb, void bitmap,
	274	ext4_group_t group);
8f6e39a7 MC	275	static void ext4_mb_return_to_preallocation(struct inode *inode,
	276	struct ext4_buddy *e4b, sector_t block,
	277	int count);
	278	static void ext4_mb_put_pa(struct ext4_allocation_context *,
	279	struct super_block , struct ext4_prealloc_space pa);
	280	static int ext4_mb_init_per_dev_proc(struct super_block *sb);
	281	static int ext4_mb_destroy_per_dev_proc(struct super_block *sb);
3e624fc7	282	static void release_blocks_on_commit(journal_t journal, transaction_t txn);
8f6e39a7 MC	283
	284
	285	static inline void ext4_lock_group(struct super_block *sb, ext4_group_t group)
	286	{
	287	struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
	288
	289	bit_spin_lock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
	290	}
	291
	292	static inline void ext4_unlock_group(struct super_block *sb,
	293	ext4_group_t group)
	294	{
	295	struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
	296
	297	bit_spin_unlock(EXT4_GROUP_INFO_LOCKED_BIT, &(grinfo->bb_state));
	298	}
	299
	300	static inline int ext4_is_group_locked(struct super_block *sb,
	301	ext4_group_t group)
	302	{
	303	struct ext4_group_info *grinfo = ext4_get_group_info(sb, group);
	304
	305	return bit_spin_is_locked(EXT4_GROUP_INFO_LOCKED_BIT,
	306	&(grinfo->bb_state));
	307	}
	308
	309	static ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
	310	struct ext4_free_extent *fex)
	311	{
	312	ext4_fsblk_t block;
	313
	314	block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb)
	315	+ fex->fe_start
	316	+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
	317	return block;
	318	}
	319	#endif