diff options
author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2008-08-18 18:00:57 -0400 |
---|---|---|
committer | Theodore Ts'o <tytso@mit.edu> | 2008-08-18 18:00:57 -0400 |
commit | 5e745b041f2ccad63077118b40468521306f3962 (patch) | |
tree | 2a4d53c884f92899ee8e4f541c32861a4a577e1d /fs/ext4/mballoc.c | |
parent | 91246c009094142f95ecc7573b7caed2bcef52c7 (diff) |
ext4: Fix small file fragmentation
For small file block allocations, mballoc uses per cpu prealloc
space. Use goal block when searching for the right prealloc
space. Also make sure ext4_da_writepages tries to write
all the pages for small files in single attempt
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/mballoc.c')
-rw-r--r-- | fs/ext4/mballoc.c | 53 |
1 files changed, 46 insertions, 7 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 865e9ddb44d..e0e3a5eb1dd 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c | |||
@@ -3282,6 +3282,35 @@ static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac, | |||
3282 | } | 3282 | } |
3283 | 3283 | ||
3284 | /* | 3284 | /* |
3285 | * Return the prealloc space that have minimal distance | ||
3286 | * from the goal block. @cpa is the prealloc | ||
3287 | * space that is having currently known minimal distance | ||
3288 | * from the goal block. | ||
3289 | */ | ||
3290 | static struct ext4_prealloc_space * | ||
3291 | ext4_mb_check_group_pa(ext4_fsblk_t goal_block, | ||
3292 | struct ext4_prealloc_space *pa, | ||
3293 | struct ext4_prealloc_space *cpa) | ||
3294 | { | ||
3295 | ext4_fsblk_t cur_distance, new_distance; | ||
3296 | |||
3297 | if (cpa == NULL) { | ||
3298 | atomic_inc(&pa->pa_count); | ||
3299 | return pa; | ||
3300 | } | ||
3301 | cur_distance = abs(goal_block - cpa->pa_pstart); | ||
3302 | new_distance = abs(goal_block - pa->pa_pstart); | ||
3303 | |||
3304 | if (cur_distance < new_distance) | ||
3305 | return cpa; | ||
3306 | |||
3307 | /* drop the previous reference */ | ||
3308 | atomic_dec(&cpa->pa_count); | ||
3309 | atomic_inc(&pa->pa_count); | ||
3310 | return pa; | ||
3311 | } | ||
3312 | |||
3313 | /* | ||
3285 | * search goal blocks in preallocated space | 3314 | * search goal blocks in preallocated space |
3286 | */ | 3315 | */ |
3287 | static noinline_for_stack int | 3316 | static noinline_for_stack int |
@@ -3290,7 +3319,8 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) | |||
3290 | int order, i; | 3319 | int order, i; |
3291 | struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); | 3320 | struct ext4_inode_info *ei = EXT4_I(ac->ac_inode); |
3292 | struct ext4_locality_group *lg; | 3321 | struct ext4_locality_group *lg; |
3293 | struct ext4_prealloc_space *pa; | 3322 | struct ext4_prealloc_space *pa, *cpa = NULL; |
3323 | ext4_fsblk_t goal_block; | ||
3294 | 3324 | ||
3295 | /* only data can be preallocated */ | 3325 | /* only data can be preallocated */ |
3296 | if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) | 3326 | if (!(ac->ac_flags & EXT4_MB_HINT_DATA)) |
@@ -3333,6 +3363,13 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) | |||
3333 | /* The max size of hash table is PREALLOC_TB_SIZE */ | 3363 | /* The max size of hash table is PREALLOC_TB_SIZE */ |
3334 | order = PREALLOC_TB_SIZE - 1; | 3364 | order = PREALLOC_TB_SIZE - 1; |
3335 | 3365 | ||
3366 | goal_block = ac->ac_g_ex.fe_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb) + | ||
3367 | ac->ac_g_ex.fe_start + | ||
3368 | le32_to_cpu(EXT4_SB(ac->ac_sb)->s_es->s_first_data_block); | ||
3369 | /* | ||
3370 | * search for the prealloc space that is having | ||
3371 | * minimal distance from the goal block. | ||
3372 | */ | ||
3336 | for (i = order; i < PREALLOC_TB_SIZE; i++) { | 3373 | for (i = order; i < PREALLOC_TB_SIZE; i++) { |
3337 | rcu_read_lock(); | 3374 | rcu_read_lock(); |
3338 | list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i], | 3375 | list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i], |
@@ -3340,17 +3377,19 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac) | |||
3340 | spin_lock(&pa->pa_lock); | 3377 | spin_lock(&pa->pa_lock); |
3341 | if (pa->pa_deleted == 0 && | 3378 | if (pa->pa_deleted == 0 && |
3342 | pa->pa_free >= ac->ac_o_ex.fe_len) { | 3379 | pa->pa_free >= ac->ac_o_ex.fe_len) { |
3343 | atomic_inc(&pa->pa_count); | 3380 | |
3344 | ext4_mb_use_group_pa(ac, pa); | 3381 | cpa = ext4_mb_check_group_pa(goal_block, |
3345 | spin_unlock(&pa->pa_lock); | 3382 | pa, cpa); |
3346 | ac->ac_criteria = 20; | ||
3347 | rcu_read_unlock(); | ||
3348 | return 1; | ||
3349 | } | 3383 | } |
3350 | spin_unlock(&pa->pa_lock); | 3384 | spin_unlock(&pa->pa_lock); |
3351 | } | 3385 | } |
3352 | rcu_read_unlock(); | 3386 | rcu_read_unlock(); |
3353 | } | 3387 | } |
3388 | if (cpa) { | ||
3389 | ext4_mb_use_group_pa(ac, cpa); | ||
3390 | ac->ac_criteria = 20; | ||
3391 | return 1; | ||
3392 | } | ||
3354 | return 0; | 3393 | return 0; |
3355 | } | 3394 | } |
3356 | 3395 | ||