linux/fs/btrfs
Filipe Manana f86f7a75e2 btrfs: use the flags of an extent map to identify the compression type
Currently, in struct extent_map, we use an unsigned int (32 bits) to
identify the compression type of an extent and an unsigned long (64 bits
on a 64 bits platform, 32 bits otherwise) for flags. We are only using
6 different flags, so an unsigned long is excessive and we can use flags
to identify the compression type instead of using a dedicated 32 bits
field.

We can easily have tens or hundreds of thousands (or more) of extent maps
on busy and large filesystems, specially with compression enabled or many
or large files with tons of small extents. So it's convenient to have the
extent_map structure as small as possible in order to use less memory.

So remove the compression type field from struct extent_map, use flags
to identify the compression type and shorten the flags field from an
unsigned long to a u32. This saves 8 bytes (on 64 bits platforms) and
reduces the size of the structure from 136 bytes down to 128 bytes, using
now only two cache lines, and increases the number of extent maps we can
have per 4K page from 30 to 32. By using a u32 for the flags instead of
an unsigned long, we no longer use test_bit(), set_bit() and clear_bit(),
but that level of atomicity is not needed as most flags are never cleared
once set (before adding an extent map to the tree), and the ones that can
be cleared or set after an extent map is added to the tree, are always
performed while holding the write lock on the extent map tree, while the
reader holds a lock on the tree or tests for a flag that never changes
once the extent map is in the tree (such as compression flags).

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15 22:59:02 +01:00
..
tests btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
accessors.c
accessors.h btrfs: qgroup: check generation when recording simple quota delta 2023-10-12 16:44:11 +02:00
acl.c
acl.h
async-thread.c btrfs: merge ordered work callbacks in btrfs_work into one 2023-10-12 16:44:10 +02:00
async-thread.h btrfs: merge ordered work callbacks in btrfs_work into one 2023-10-12 16:44:10 +02:00
backref.c for-6.7-tag 2023-10-30 10:42:06 -10:00
backref.h for-6.7-tag 2023-10-30 10:42:06 -10:00
bio.c btrfs: merge ordered work callbacks in btrfs_work into one 2023-10-12 16:44:10 +02:00
bio.h btrfs: add an ordered_extent pointer to struct btrfs_bio 2023-06-19 13:59:36 +02:00
block-group.c btrfs: remove stripe size local variable from insert_dev_extents() 2023-12-15 20:27:02 +01:00
block-group.h btrfs: use a dedicated data structure for chunk maps 2023-12-15 20:27:02 +01:00
block-rsv.c btrfs: read raid stripe tree from disk 2023-10-12 16:44:09 +02:00
block-rsv.h btrfs: move btrfs_check_trunc_cache_free_space into block-rsv.c 2023-06-19 13:59:24 +02:00
btrfs_inode.h btrfs: allocate btrfs_inode::file_extent_tree only without NO_HOLES 2023-12-15 22:59:01 +01:00
compression.c btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
compression.h btrfs: use page alloc/free wrappers for compression pages 2023-12-15 20:27:01 +01:00
ctree.c btrfs: make the logic from btrfs_block_can_be_shared() easier to read 2023-12-15 20:27:00 +01:00
ctree.h btrfs: remove unused btrfs_root::type 2023-12-15 20:27:01 +01:00
defrag.c btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
defrag.h btrfs: move btrfs_defrag_root() to defrag.{c,h} 2023-10-12 16:44:13 +02:00
delalloc-space.c btrfs: fix qgroup_free_reserved_data int overflow 2023-12-06 22:32:46 +01:00
delalloc-space.h
delayed-inode.c btrfs: do not utilize goto to implement delayed inode ref deletion 2023-12-15 20:27:00 +01:00
delayed-inode.h btrfs: remove redundant root argument from btrfs_delayed_update_inode() 2023-10-12 16:44:12 +02:00
delayed-ref.c btrfs: fix qgroup record leaks when using simple quotas 2023-11-09 14:01:59 +01:00
delayed-ref.h btrfs: stop reserving excessive space for block group item insertions 2023-10-12 16:44:16 +02:00
dev-replace.c btrfs: use a dedicated data structure for chunk maps 2023-12-15 20:27:02 +01:00
dev-replace.h
dir-item.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-10-12 16:44:07 +02:00
dir-item.h btrfs: add fscrypt related dependencies to respective headers 2023-10-12 16:44:02 +02:00
discard.c btrfs: unexport btrfs_run_discard_work and make it static 2023-06-19 13:59:25 +02:00
discard.h btrfs: unexport btrfs_run_discard_work and make it static 2023-06-19 13:59:25 +02:00
disk-io.c btrfs: set clear_cache if we use usebackuproot 2023-12-15 20:27:05 +01:00
disk-io.h btrfs: move one shot mount option clearing to super.c 2023-12-15 20:27:04 +01:00
export.c
export.h
extent_io.c btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
extent_io.h btrfs: allow extent buffer helpers to skip cross-page handling 2023-12-15 20:27:03 +01:00
extent_map.c btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
extent_map.h btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
extent-io-tree.c btrfs: allocate btrfs_inode::file_extent_tree only without NO_HOLES 2023-12-15 22:59:01 +01:00
extent-io-tree.h btrfs: always set extent_io_tree::inode and drop fs_info 2023-12-15 20:27:02 +01:00
extent-tree.c btrfs: reflow btrfs_free_tree_block 2023-12-15 20:27:03 +01:00
extent-tree.h btrfs: get correct owning_root when dropping snapshot 2023-11-03 16:39:06 +01:00
file-item.c btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
file-item.h btrfs: scrub: avoid unnecessary csum tree search preparing stripes 2023-08-21 14:54:48 +02:00
file.c btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
file.h
free-space-cache.c btrfs: remove redundant root argument from btrfs_update_inode() 2023-10-12 16:44:12 +02:00
free-space-cache.h btrfs: move btrfs_check_trunc_cache_free_space into block-rsv.c 2023-06-19 13:59:24 +02:00
free-space-tree.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-10-12 16:44:07 +02:00
free-space-tree.h btrfs: make clear_cache mount option to rebuild FST without disabling it 2023-05-10 14:51:27 +02:00
fs.c
fs.h btrfs: remove old mount API code 2023-12-15 20:27:04 +01:00
inode-item.c btrfs: track owning root in btrfs_ref 2023-10-12 16:44:11 +02:00
inode-item.h btrfs: add fscrypt related dependencies to respective headers 2023-10-12 16:44:02 +02:00
inode.c btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
ioctl.c for-6.7-rc3-tag 2023-11-28 11:16:04 -08:00
ioctl.h
Kconfig btrfs: check-integrity: remove CONFIG_BTRFS_FS_CHECK_INTEGRITY option 2023-10-12 16:44:05 +02:00
locking.c btrfs: add raid stripe tree definitions 2023-10-12 16:44:09 +02:00
locking.h btrfs: do not block starts waiting on previous transaction commit 2023-09-08 14:10:49 +02:00
lru_cache.c
lru_cache.h
lzo.c btrfs: use page alloc/free wrappers for compression pages 2023-12-15 20:27:01 +01:00
Makefile btrfs: add support for inserting raid stripe extents 2023-10-12 16:44:09 +02:00
messages.c btrfs: constify fs_info parameter in __btrfs_panic() 2023-12-15 20:27:02 +01:00
messages.h btrfs: constify fs_info parameter in __btrfs_panic() 2023-12-15 20:27:02 +01:00
misc.h minmax: add in_range() macro 2023-08-24 16:20:18 -07:00
ordered-data.c btrfs: fix qgroup_free_reserved_data int overflow 2023-12-06 22:32:46 +01:00
ordered-data.h btrfs: remove unused btrfs_ordered_extent::outstanding_isize 2023-12-15 20:27:01 +01:00
orphan.c
orphan.h
print-tree.c btrfs: new inline ref storing owning subvol of data extents 2023-10-12 16:44:11 +02:00
print-tree.h btrfs: print-tree: pass const extent buffer pointer 2023-06-19 13:59:22 +02:00
props.c btrfs: move btrfs_name_hash to dir-item.h 2023-10-12 16:44:02 +02:00
props.h
qgroup.c btrfs: ensure releasing squota reserve on head refs 2023-12-06 22:32:57 +01:00
qgroup.h btrfs: ensure releasing squota reserve on head refs 2023-12-06 22:32:57 +01:00
raid56.c btrfs: raid56: remove unused btrfs_plug_cb::work 2023-12-15 20:27:01 +01:00
raid56.h btrfs: use a dedicated data structure for chunk maps 2023-12-15 20:27:02 +01:00
raid-stripe-tree.c btrfs: directly return 0 on no error code in btrfs_insert_raid_extent() 2023-11-03 16:38:51 +01:00
raid-stripe-tree.h btrfs: zoned: support RAID0/1/10 on top of raid stripe tree 2023-10-12 16:44:09 +02:00
rcu-string.h
ref-verify.c btrfs: ref-verify: fix memory leaks in btrfs_ref_tree_mod() 2023-11-23 22:27:34 +01:00
ref-verify.h
reflink.c for-6.7-tag 2023-10-30 10:42:06 -10:00
reflink.h
relocation.c btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
relocation.h btrfs: relocation: constify parameters where possible 2023-10-12 16:44:13 +02:00
root-tree.c btrfs: qgroup: add new quota mode for simple quotas 2023-10-12 16:44:10 +02:00
root-tree.h btrfs: drop __must_check annotations 2023-10-12 16:44:04 +02:00
scrub.c btrfs: use a dedicated data structure for chunk maps 2023-12-15 20:27:02 +01:00
scrub.h
send.c btrfs: send: ensure send_fd is writable 2023-11-24 18:50:53 +01:00
send.h
space-info.c btrfs: adjust overcommit logic when very close to full 2023-10-12 16:44:16 +02:00
space-info.h btrfs: pass a space_info argument to btrfs_reserve_metadata_bytes() 2023-10-12 16:44:05 +02:00
subpage.c btrfs: migrate to use folio private instead of page private 2023-12-15 20:27:01 +01:00
subpage.h btrfs: stop setting PageError in the data I/O path 2023-06-19 13:59:35 +02:00
super.c btrfs: remove code for inode_cache and recovery mount options 2023-12-15 20:27:05 +01:00
super.h btrfs: remove old mount API code 2023-12-15 20:27:04 +01:00
sysfs.c btrfs: sysfs: show temp_fsid feature 2023-10-12 16:44:18 +02:00
sysfs.h
transaction.c for-6.7-rc5-tag 2023-12-14 11:53:00 -08:00
transaction.h btrfs: free qgroup pertrans reserve on transaction abort 2023-12-06 22:32:49 +01:00
tree-checker.c btrfs: tree-checker: add type and sequence check for inline backrefs 2023-11-15 17:08:09 +01:00
tree-checker.h btrfs: move btrfs_verify_level_key into tree-checker.c 2023-06-19 13:59:25 +02:00
tree-log.c btrfs: use the flags of an extent map to identify the compression type 2023-12-15 22:59:02 +01:00
tree-log.h btrfs: change for_rename argument of btrfs_record_unlink_dir() to bool 2023-06-19 13:59:26 +02:00
tree-mod-log.c btrfs: avoid tree mod log ENOMEM failures when we don't need to log 2023-06-19 13:59:38 +02:00
tree-mod-log.h
ulist.c btrfs: reformat remaining kdoc style comments 2023-10-12 16:44:04 +02:00
ulist.h
uuid-tree.c btrfs: abort transaction on generation mismatch when marking eb as dirty 2023-10-12 16:44:07 +02:00
uuid-tree.h
verity.c btrfs: remove redundant root argument from btrfs_update_inode() 2023-10-12 16:44:12 +02:00
verity.h
volumes.c btrfs: use a dedicated data structure for chunk maps 2023-12-15 20:27:02 +01:00
volumes.h btrfs: use a dedicated data structure for chunk maps 2023-12-15 20:27:02 +01:00
xattr.c btrfs: cache that we don't have security.capability set 2023-12-15 20:27:05 +01:00
xattr.h btrfs: move btrfs_xattr_handlers to .rodata 2023-10-09 16:24:17 +02:00
zlib.c btrfs: use page alloc/free wrappers for compression pages 2023-12-15 20:27:01 +01:00
zoned.c btrfs: add reconfigure callback for fs_context 2023-12-15 20:27:04 +01:00
zoned.h btrfs: add reconfigure callback for fs_context 2023-12-15 20:27:04 +01:00
zstd.c btrfs: use page alloc/free wrappers for compression pages 2023-12-15 20:27:01 +01:00