From: Weixie Cui The if-else ladder in ext4_mb_normalize_request() manually rounds up the preallocation size to the next power of two for files up to 1MB, enumerating each step from 16KB to 1MB individually. Replace this with a single roundup_pow_of_two() call clamped to a 16KB minimum, which is functionally equivalent but much more concise. Also replace raw byte constants with SZ_1M and SZ_16K from for clarity, and remove the stale "XXX: should this table be tunable?" comment that has been there since the original mballoc code. No functional change. Reviewed-by: Andreas Dilger Signed-off-by: Weixie Cui --- v4: - Drop unnecessary braces around single-line if/else as suggested by Andreas Dilger v3: - Replace raw constants with SZ_1M/SZ_16K - Remove stale XXX comment --- fs/ext4/mballoc.c | 24 +++++++++--------------- 1 file changed, 9 insertions(+), 15 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 20e9fdaf4301..1d6efba97835 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -4561,22 +4561,16 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac, (req <= (size) || max <= (chunk_size)) /* first, try to predict filesize */ - /* XXX: should this table be tunable? */ start_off = 0; - if (size <= 16 * 1024) { - size = 16 * 1024; - } else if (size <= 32 * 1024) { - size = 32 * 1024; - } else if (size <= 64 * 1024) { - size = 64 * 1024; - } else if (size <= 128 * 1024) { - size = 128 * 1024; - } else if (size <= 256 * 1024) { - size = 256 * 1024; - } else if (size <= 512 * 1024) { - size = 512 * 1024; - } else if (size <= 1024 * 1024) { - size = 1024 * 1024; + if (size <= SZ_1M) { + /* + * For files up to 1MB, round up the preallocation size to + * the next power of two, with a minimum of 16KB. + */ + if (size <= (unsigned long)SZ_16K) + size = SZ_16K; + else + size = roundup_pow_of_two(size); } else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) { start_off = ((loff_t)ac->ac_o_ex.fe_logical >> (21 - bsbits)) << 21; -- 2.39.5 (Apple Git-154)