fs/ext4/mballoc.h - kernel/msm - Gitiles

 /*
  *  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 "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
 	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;
 };
 #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
	/*
	* 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 "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
	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;
	};
	#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