diff options
Diffstat (limited to 'fs/ext4/ext4.h')
| -rw-r--r-- | fs/ext4/ext4.h | 45 |
1 files changed, 25 insertions, 20 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 6a1f013d23f7..45a531446ea2 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -128,47 +128,52 @@ enum SHIFT_DIRECTION { }; /* - * Number of criterias defined. For each criteria, mballoc has slightly - * different way of finding the required blocks nad usually, higher the - * criteria the slower the allocation. We start at lower criterias and keep - * falling back to higher ones if we are not able to find any blocks. - */ -#define EXT4_MB_NUM_CRS 5 -/* - * All possible allocation criterias for mballoc. Lower are faster. + * For each criteria, mballoc has slightly different way of finding + * the required blocks nad usually, higher the criteria the slower the + * allocation. We start at lower criterias and keep falling back to + * higher ones if we are not able to find any blocks. Lower (earlier) + * criteria are faster. */ enum criteria { /* - * Used when number of blocks needed is a power of 2. This doesn't - * trigger any disk IO except prefetch and is the fastest criteria. + * Used when number of blocks needed is a power of 2. This + * doesn't trigger any disk IO except prefetch and is the + * fastest criteria. */ CR_POWER2_ALIGNED, /* - * Tries to lookup in-memory data structures to find the most suitable - * group that satisfies goal request. No disk IO except block prefetch. + * Tries to lookup in-memory data structures to find the most + * suitable group that satisfies goal request. No disk IO + * except block prefetch. */ CR_GOAL_LEN_FAST, /* - * Same as CR_GOAL_LEN_FAST but is allowed to reduce the goal length to - * the best available length for faster allocation. + * Same as CR_GOAL_LEN_FAST but is allowed to reduce the goal + * length to the best available length for faster allocation. */ CR_BEST_AVAIL_LEN, /* - * Reads each block group sequentially, performing disk IO if necessary, to - * find find_suitable block group. Tries to allocate goal length but might trim - * the request if nothing is found after enough tries. + * Reads each block group sequentially, performing disk IO if + * necessary, to find find_suitable block group. Tries to + * allocate goal length but might trim the request if nothing + * is found after enough tries. */ CR_GOAL_LEN_SLOW, /* - * Finds the first free set of blocks and allocates those. This is only - * used in rare cases when CR_GOAL_LEN_SLOW also fails to allocate - * anything. + * Finds the first free set of blocks and allocates + * those. This is only used in rare cases when + * CR_GOAL_LEN_SLOW also fails to allocate anything. */ CR_ANY_FREE, + + /* + * Number of criterias defined. + */ + EXT4_MB_NUM_CRS }; /* criteria below which we use fast block scanning and avoid unnecessary IO */ |