DragonFly-2.3.1.329.g5a64ef master sys/vfs/hammer hammer.h hamme
commit 5a64efa13fd54a45eec98cf4f8a8ee56842bf811
Author: Matthew Dillon <dillon@apollo.backplane.com>
Date: Sat Jun 20 19:29:57 2009 -0700
HAMMER VFS - Implement inode number matching against the directory hash
Change hammer_create_inode() and hammer_alloc_objid() to take the upper
10 bits of the filename hash and attempt to use them as the lower 10 bits
of the inode number.
hammer_alloc_objid() now utilizes a small two-level 1024-bit bitmap to
assign the low 10 bits of the inode number, on a per-directory basis.
If a collision occurs a nearby value is used instead.
The idea is for inode numbers to have approximately the same linearity
as the directory read scan order, so programs such as cpio, tar, cpdup,
find, and ls which do recursive scans of the directory tree get much
better locality of reference for stat() and other related system calls.
Based-on: Numerous discussions with people, esp corecode.
Summary of changes:
sys/vfs/hammer/hammer.h | 13 +++++-
sys/vfs/hammer/hammer_inode.c | 14 +++++--
sys/vfs/hammer/hammer_transaction.c | 76 ++++++++++++++++++++++++++++++----
sys/vfs/hammer/hammer_vnops.c | 13 ++++--
4 files changed, 95 insertions(+), 21 deletions(-)
http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/5a64efa13fd54a45eec98cf4f8a8ee56842bf811
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