mirror of https://gitee.com/openkylin/linux.git
689110098c
Currently in when getting the block group number for a particular block in ext4_block_in_group() we're using ext4_get_group_no_and_offset() which uses do_div() to get the block group and the remainer which is offset within the group. We don't need all of that in ext4_block_in_group() as we only need to figure out the group number. This commit changes ext4_block_in_group() to calculate group number directly. This shows as a big improvement with regards to cpu utilization. Measuring fallocate -l 15T on fresh file system with perf showed that 23% of cpu time was spend in the ext4_get_group_no_and_offset(). With this change it completely disappears from the list only bumping the occurrence of ext4_init_block_bitmap() which is the biggest user of ext4_block_in_group() by 4%. As the result of this change on my system the fallocate call was approx. 10% faster. However since there is '-g' option in mkfs which allow us setting different groups size (mostly for developers) I've introduced new per file system flag whether we have a standard block group size or not. The flag is used to determine whether we can use the bit shift optimization or not. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> |
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| .. | ||
| Kconfig | ||
| Makefile | ||
| acl.c | ||
| acl.h | ||
| balloc.c | ||
| bitmap.c | ||
| block_validity.c | ||
| dir.c | ||
| ext4.h | ||
| ext4_extents.h | ||
| ext4_jbd2.c | ||
| ext4_jbd2.h | ||
| extents.c | ||
| extents_status.c | ||
| extents_status.h | ||
| file.c | ||
| fsync.c | ||
| hash.c | ||
| ialloc.c | ||
| indirect.c | ||
| inline.c | ||
| inode.c | ||
| ioctl.c | ||
| mballoc.c | ||
| mballoc.h | ||
| migrate.c | ||
| mmp.c | ||
| move_extent.c | ||
| namei.c | ||
| page-io.c | ||
| resize.c | ||
| super.c | ||
| symlink.c | ||
| truncate.h | ||
| xattr.c | ||
| xattr.h | ||
| xattr_security.c | ||
| xattr_trusted.c | ||
| xattr_user.c | ||