From: Yongpeng Yang <[email protected]>
Changes since v1:
- Introduce tracepoints for f2fs_iext_update_data_blkaddr and
f2fs_iext_lookup_blkaddr to aid debugging (new patch 5/5).
- Bypass inline extent lookup for F2FS_GET_BLOCK_PRECACHE to ensure all
mappings are loaded into the read extent cache.
- Unify the check for fofs exceeding direct_blocks range to use
"fofs >= direct_blocks" consistently.
- Remove support for caching NULL_ADDR in inline extent area. If a fofs
within [0, direct_blocks) is not found in inline extent, it implies
NULL_ADDR. This simplifies merge and split logic.
- Fix f2fs_iext_enable_inline_extent to use PTR_ERR instead of -ENOMEM.
- Change f2fs_iext_convert_to_inline_extent return type to bool.
- Add benchmark data covering 4K/8K/32K/64K random read.
- Rename __is_extent_mergeable to __is_iextent_mergeable to avoid
naming collision with extent cache code.
- Remove inode parameter from f2fs_iext_sanity_check (always NULL).
- Reduce #ifdef CONFIG_F2FS_INLINE_EXTENT nesting in node.c.
- Code style fixes to comply with kernel coding style.
This patchset introduces an inline extent mapping mechanism for f2fs.
Instead of storing individual block addresses in the inode's data block
address area (i_addr[]), this feature packs contiguous block ranges into
compact extent entries, significantly reducing the number of entries
needed and enabling faster block address lookups via binary search.
The inline extent format is identified by magic numbers in the inode
data area and is transparent to the rest of f2fs -- when the extent
area is full or cannot represent the mapping efficiently, it
automatically converts back to the direct block address format.
Patch 1: Preparatory refactoring -- replace raw pointer arithmetic
with f2fs_data_blkaddr() to abstract block address access.
Patch 2: Core implementation -- data structures, extent operations
(lookup, insert, merge, split, truncate), format conversion,
and integration with f2fs data/node paths.
Patch 3: ioctl interface -- allow per-file enable/disable of inline
extent format via F2FS_EXTENT_FL flag.
Patch 4: sysfs interface -- runtime enable/disable toggle and file
extension list for automatic inline extent activation.
Patch 5: Tracepoints for inline extent lookup and update operations.
Test setup and results:
=======================
Platform: Xiaomi smartphone, UFS 4.0 storage
# Enable inline extent
echo 1 > /sys/fs/f2fs/<dev>/inline_extent_enable
echo 'mp4' > /sys/fs/f2fs/<dev>/inline_extent_extension_list
# Prepare data: write with 4K offset stride to create fragmented
# extents, then overwrite sequentially so inline extent can cache
# all mappings in compact form.
fio --name=test --filename=data.mp4 --rw=write:4k --bs=64M \
--size=8G --ioengine=libaio --direct=1
sync
fio --name=test --filename=data.mp4 --rw=write --bs=64M \
--size=8G --ioengine=libaio --direct=1
sync
echo 3 > /proc/sys/vm/drop_caches
# Benchmark: random buffered read, 1GB total IO
fio --name=buffer-read --ioengine=libaio --rw=randread --bs=$BS \
--size=8G --io_size=1G --numjobs=1 --filename=data.mp4
Results (random read bandwidth, MiB/s):
+---------------------------------------------------+
| BS | baseline | inline ext | improvement |
|--------+----------+------------+------------------|
| 4K | 35 | 36 | +2.5% |
| 8K | 60 | 62 | +3% |
| 32K | 179 | 191 | +6.8% |
| 64K | 284 | 321 | +13% |
+---------------------------------------------------+
The improvement comes from eliminating direct/indirect node page reads
during block address lookup -- all mappings are stored directly in
the inode page and found via O(log n) binary search.
Yongpeng Yang (5):
f2fs: replace raw dnode pointer arithmetic with f2fs_data_blkaddr()
f2fs: introduce inline extent mapping for inode data blocks
f2fs: support setting inline extent flag via ioctl
f2fs: add sysfs interface for inline extent management
f2fs: introduce tracepoints for inline extent lookup and update
fs/f2fs/Kconfig | 18 +
fs/f2fs/Makefile | 1 +
fs/f2fs/data.c | 157 ++++++-
fs/f2fs/debug.c | 4 +
fs/f2fs/dir.c | 9 +
fs/f2fs/f2fs.h | 23 +-
fs/f2fs/file.c | 93 +++-
fs/f2fs/iextent.c | 873 ++++++++++++++++++++++++++++++++++++
fs/f2fs/iextent.h | 187 ++++++++
fs/f2fs/inline.c | 7 +
fs/f2fs/namei.c | 48 ++
fs/f2fs/node.c | 66 ++-
fs/f2fs/node.h | 4 +
fs/f2fs/recovery.c | 17 +
fs/f2fs/super.c | 13 +
fs/f2fs/sysfs.c | 52 +++
include/trace/events/f2fs.h | 79 ++++
17 files changed, 1635 insertions(+), 16 deletions(-)
create mode 100644 fs/f2fs/iextent.c
create mode 100644 fs/f2fs/iextent.h
--
2.43.0
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