/* * 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