diff options
Diffstat (limited to 'fs/ext4/mballoc.h')
| -rw-r--r-- | fs/ext4/mballoc.h | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h new file mode 100644 index 00000000..c070618c --- /dev/null +++ b/fs/ext4/mballoc.h @@ -0,0 +1,222 @@ +/* + * 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 { + /* MUST be the first member */ + struct ext4_journal_cb_entry efd_jce; + + /* ext4_free_data private data starts from here */ + + /* this links the free block information from group_info */ + struct rb_node efd_node; + + /* group which free block extent belongs */ + ext4_group_t efd_group; + + /* free block extent */ + ext4_grpblk_t efd_start_cluster; + ext4_grpblk_t efd_count; + + /* transaction which freed this extent */ + tid_t efd_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; /* In cluster units */ + ext4_group_t fe_group; + ext4_grpblk_t fe_len; /* In cluster units */ +}; + +/* + * 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 best 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_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_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; +}; + +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 << EXT4_SB(sb)->s_cluster_bits); +} +#endif |