The following set of patches shrink the size of ext4_inode_info, which
is present in memory for every single ext4 inode in the inode cache.
For example, on one of my machines I currently have 172261 ext4 inodes
in my cache, which represents 161 megabytes of memory. On an x86_64
machine, these patches allow me to shrink the ext4 in-core inode size
from 952 bytes to 872 bytes. This represents a 8.4% decrease. Using
the SLUB allocator, this means we can now fit 18 inodes into an order 4
(16384 bytes) slab, instead of the previous 17 inodes. This results in
an effective decrease of 5.6% of memory consumption by the ext4 inode
cache.
It would be possible to further slim down the ext4_inode_cache by
another 100 bytes or so, by breaking the ext4_inode_info into the
portion of the inode required a file is opened for writing, and
everything else. That would be a fairly disruptive change, though, so
I'll save that for another time.
- Ted
Theodore Ts'o (6):
ext4: replace i_delalloc_reserved_flag with
EXT4_STATE_DELALLOC_RESERVED
ext4: Use ext4_lblk_t instead of sector_t for logical blocks
ext4: Drop ec_type from the ext4_ext_cache structure
ext4: reorder ext4_inode_info structure elements to remove unneeded
padding
ext4: Drop i_state_flags on architectures with 64-bit longs
ext4: Dynamically allocate the jbd2_inode in ext4_inode_info as
necessary
fs/ext4/balloc.c | 3 ++-
fs/ext4/ext4.h | 36 +++++++++++++++++++++++-------------
fs/ext4/ext4_extents.h | 8 ++------
fs/ext4/ext4_jbd2.h | 2 +-
fs/ext4/extents.c | 39 ++++++++++++++++-----------------------
fs/ext4/file.c | 19 +++++++++++++++++++
fs/ext4/ialloc.c | 2 +-
fs/ext4/inode.c | 29 ++++++++++++++++++-----------
fs/ext4/mballoc.c | 5 +++--
fs/ext4/super.c | 17 +++++++----------
fs/jbd2/journal.c | 20 +++++++++++++-------
include/linux/jbd2.h | 20 ++++++++++++++++++--
12 files changed, 123 insertions(+), 77 deletions(-)
--
1.7.3.1
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