[mirror_ubuntu-artful-kernel.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/mutex.h>
#include "ext4_jbd2.h"
#include "ext4.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


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_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_type;	/* pa type. inode or group */
	spinlock_t		*pa_obj_lock;
	struct inode		*pa_inode;	/* hack, for history only */
};

enum {
	MB_INODE_PA = 0,
	MB_GROUP_PA = 1
};

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;
	/*
	 * pointer to the held semaphore upon successful
	 * block allocation
	 */
	struct rw_semaphore *alloc_semp;
	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;
}
#endif

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

static inline 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	21	#include <linux/blkdev.h>
920313a7	22	#include <linux/mutex.h>
8f6e39a7 MC	23	#include "ext4_jbd2.h"
8f6e39a7 MC	24	#include "ext4.h"
8f6e39a7 MC	25
	26	/*
	27	* with AGGRESSIVE_CHECK allocator runs consistency checks over
	28	* structures. these checks slow things down a lot
	29	*/
	30	#define AGGRESSIVE_CHECK__
	31
	32	/*
	33	* with DOUBLE_CHECK defined mballoc creates persistent in-core
	34	* bitmaps, maintains and uses them to check for double allocations
	35	*/
	36	#define DOUBLE_CHECK__
	37
	38	/*
	39	*/
	40	#define MB_DEBUG__
	41	#ifdef MB_DEBUG
	42	#define mb_debug(fmt, a...) printk(fmt, ##a)
	43	#else
	44	#define mb_debug(fmt, a...)
	45	#endif
	46
	47	/*
	48	* with EXT4_MB_HISTORY mballoc stores last N allocations in memory
	49	* and you can monitor it in /proc/fs/ext4/<dev>/mb_history
	50	*/
	51	#define EXT4_MB_HISTORY
	52	#define EXT4_MB_HISTORY_ALLOC 1 /* allocation */
	53	#define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */
	54	#define EXT4_MB_HISTORY_DISCARD 4 /* preallocation discarded */
	55	#define EXT4_MB_HISTORY_FREE 8 /* free */
	56
	57	#define EXT4_MB_HISTORY_DEFAULT (EXT4_MB_HISTORY_ALLOC \| \
	58	EXT4_MB_HISTORY_PREALLOC)
	59
	60	/*
	61	* How long mballoc can look for a best extent (in found extents)
	62	*/
	63	#define MB_DEFAULT_MAX_TO_SCAN 200
	64
	65	/*
	66	* How long mballoc must look for a best extent
	67	*/
	68	#define MB_DEFAULT_MIN_TO_SCAN 10
	69
	70	/*
	71	* How many groups mballoc will scan looking for the best chunk
	72	*/
	73	#define MB_DEFAULT_MAX_GROUPS_TO_SCAN 5
	74
	75	/*
	76	* with 'ext4_mb_stats' allocator will collect stats that will be
	77	* shown at umount. The collecting costs though!
	78	*/
	79	#define MB_DEFAULT_STATS 1
	80
	81	/*
	82	* files smaller than MB_DEFAULT_STREAM_THRESHOLD are served
	83	* by the stream allocator, which purpose is to pack requests
	84	* as close each to other as possible to produce smooth I/O traffic
	85	* We use locality group prealloc space for stream request.
	86	* We can tune the same via /proc/fs/ext4/<parition>/stream_req
	87	*/
	88	#define MB_DEFAULT_STREAM_THRESHOLD 16 /* 64K */
89
90	/*
91	* for which requests use 2^N search using buddies
92	*/
93	#define MB_DEFAULT_ORDER2_REQS 2
94
95	/*
96	* default group prealloc size 512 blocks
97	*/
98	#define MB_DEFAULT_GROUP_PREALLOC 512
99
8f6e39a7	100
c894058d AK	101	struct ext4_free_data {
	102	/* this links the free block information from group_info */
	103	struct rb_node node;
8f6e39a7	104
c894058d	105	/* this links the free block information from ext4_sb_info */
8f6e39a7	106	struct list_head list;
c894058d AK	107
	108	/* group which free block extent belongs */
	109	ext4_group_t group;
	110
	111	/* free block extent */
	112	ext4_grpblk_t start_blk;
	113	ext4_grpblk_t count;
	114
	115	/* transaction which freed this extent */
	116	tid_t t_tid;
8f6e39a7 MC	117	};
8f6e39a7 MC	118
8f6e39a7 MC	119	struct ext4_prealloc_space {
	120	struct list_head pa_inode_list;
	121	struct list_head pa_group_list;
	122	union {
	123	struct list_head pa_tmp_list;
	124	struct rcu_head pa_rcu;
	125	} u;
	126	spinlock_t pa_lock;
	127	atomic_t pa_count;
	128	unsigned pa_deleted;
	129	ext4_fsblk_t pa_pstart; /* phys. block */
	130	ext4_lblk_t pa_lstart; /* log. block */
	131	unsigned short pa_len; /* len of preallocated chunk */
	132	unsigned short pa_free; /* how many blocks are free */
cc0fb9ad	133	unsigned short pa_type; /* pa type. inode or group */
8f6e39a7 MC	134	spinlock_t *pa_obj_lock;
	135	struct inode pa_inode; / hack, for history only */
	136	};
	137
cc0fb9ad AK	138	enum {
	139	MB_INODE_PA = 0,
	140	MB_GROUP_PA = 1
	141	};
8f6e39a7 MC	142
	143	struct ext4_free_extent {
	144	ext4_lblk_t fe_logical;
	145	ext4_grpblk_t fe_start;
	146	ext4_group_t fe_group;
	147	int fe_len;
	148	};
	149
	150	/*
	151	* Locality group:
	152	* we try to group all related changes together
	153	* so that writeback can flush/allocate them together as well
6be2ded1 AK	154	* Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
	155	* (512). We store prealloc space into the hash based on the pa_free blocks
	156	* order value.ie, fls(pa_free)-1;
8f6e39a7	157	*/
6be2ded1	158	#define PREALLOC_TB_SIZE 10
8f6e39a7 MC	159	struct ext4_locality_group {
8f6e39a7 MC	160	/* for allocator */
6be2ded1 AK	161	/* to serialize allocates */
	162	struct mutex lg_mutex;
	163	/* list of preallocations */
	164	struct list_head lg_prealloc_list[PREALLOC_TB_SIZE];
8f6e39a7 MC	165	spinlock_t lg_prealloc_lock;
	166	};
	167
	168	struct ext4_allocation_context {
	169	struct inode *ac_inode;
	170	struct super_block *ac_sb;
	171
	172	/* original request */
	173	struct ext4_free_extent ac_o_ex;
	174
	175	/* goal request (after normalization) */
	176	struct ext4_free_extent ac_g_ex;
	177
	178	/* the best found extent */
	179	struct ext4_free_extent ac_b_ex;
	180
	181	/* copy of the bext found extent taken before preallocation efforts */
	182	struct ext4_free_extent ac_f_ex;
	183
	184	/* number of iterations done. we have to track to limit searching */
	185	unsigned long ac_ex_scanned;
	186	__u16 ac_groups_scanned;
	187	__u16 ac_found;
	188	__u16 ac_tail;
	189	__u16 ac_buddy;
	190	__u16 ac_flags; /* allocation hints */
	191	__u8 ac_status;
	192	__u8 ac_criteria;
	193	__u8 ac_repeats;
	194	__u8 ac_2order; /* if request is to allocate 2^N blocks and
	195	* N > 0, the field stores N, otherwise 0 */
	196	__u8 ac_op; /* operation, for history only */
	197	struct page *ac_bitmap_page;
	198	struct page *ac_buddy_page;
8556e8f3 AK	199	/*
	200	* pointer to the held semaphore upon successful
	201	* block allocation
	202	*/
	203	struct rw_semaphore *alloc_semp;
8f6e39a7 MC	204	struct ext4_prealloc_space *ac_pa;
	205	struct ext4_locality_group *ac_lg;
	206	};
	207
	208	#define AC_STATUS_CONTINUE 1
	209	#define AC_STATUS_FOUND 2
	210	#define AC_STATUS_BREAK 3
	211
	212	struct ext4_mb_history {
	213	struct ext4_free_extent orig; /* orig allocation */
	214	struct ext4_free_extent goal; /* goal allocation */
	215	struct ext4_free_extent result; /* result allocation */
	216	unsigned pid;
	217	unsigned ino;
	218	__u16 found; /* how many extents have been found */
	219	__u16 groups; /* how many groups have been scanned */
	220	__u16 tail; /* what tail broke some buddy */
	221	__u16 buddy; /* buddy the tail ^^^ broke */
	222	__u16 flags;
	223	__u8 cr:3; /* which phase the result extent was found at */
	224	__u8 op:4;
	225	__u8 merged:1;
	226	};
	227
	228	struct ext4_buddy {
	229	struct page *bd_buddy_page;
	230	void *bd_buddy;
	231	struct page *bd_bitmap_page;
	232	void *bd_bitmap;
	233	struct ext4_group_info *bd_info;
	234	struct super_block *bd_sb;
	235	__u16 bd_blkbits;
	236	ext4_group_t bd_group;
920313a7	237	struct rw_semaphore *alloc_semp;
8f6e39a7 MC	238	};
	239	#define EXT4_MB_BITMAP(e4b) ((e4b)->bd_bitmap)
	240	#define EXT4_MB_BUDDY(e4b) ((e4b)->bd_buddy)
	241
	242	#ifndef EXT4_MB_HISTORY
	243	static inline void ext4_mb_store_history(struct ext4_allocation_context *ac)
	244	{
	245	return;
	246	}
8f6e39a7 MC	247	#endif
	248
	249	#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
	250
c3a326a6	251	static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
8f6e39a7 MC	252	struct ext4_free_extent *fex)
	253	{
	254	ext4_fsblk_t block;
	255
	256	block = (ext4_fsblk_t) fex->fe_group * EXT4_BLOCKS_PER_GROUP(sb)
	257	+ fex->fe_start
	258	+ le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
	259	return block;
	260	}
	261	#endif