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/*
* 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/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__
/*
*/
#ifdef CONFIG_EXT4_DEBUG
extern u8 mb_enable_debug;
#define mb_debug(n, fmt, a...) \
do { \
if ((n) <= mb_enable_debug) { \
printk(KERN_DEBUG "(%s, %d): %s: ", \
__FILE__, __LINE__, __func__); \
printk(fmt, ## a); \
} \
} while (0)
#else
#define mb_debug(n, fmt, a...)
#endif
#define EXT4_MB_HISTORY_ALLOC 1 /* allocation */
#define EXT4_MB_HISTORY_PREALLOC 2 /* preallocated blocks used */
/*
* 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 0
/*
* 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 */
ext4_grpblk_t pa_len; /* len of preallocated chunk */
ext4_grpblk_t 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;
ext4_grpblk_t 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 (normalized ac_o_ex) */
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_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)
static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
struct ext4_free_extent *fex)
{
return ext4_group_first_block_no(sb, fex->fe_group) + fex->fe_start;
}
#endif
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