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authorLinus Torvalds <torvalds@linux-foundation.org>2014-04-07 10:55:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-07 10:55:36 -0700
commit3021112598d2b722eee54d8a662fea2089abbdbc (patch)
tree640c5f7b1d8ece378e3e67bd3c401c80b40ecea8 /Documentation
parent0af9fb63915cf5ebb47b5c9ff16526b47545baf5 (diff)
parent48b230a583965d33c32b4e3c29a1e5e15d7e55de (diff)
Merge tag 'for-f2fs-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs updates from Jaegeuk Kim: "This patch-set includes the following major enhancement patches. - introduce large directory support - introduce f2fs_issue_flush to merge redundant flush commands - merge write IOs as much as possible aligned to the segment - add sysfs entries to tune the f2fs configuration - use radix_tree for the free_nid_list to reduce in-memory operations - remove costly bit operations in f2fs_find_entry - enhance the readahead flow for CP/NAT/SIT/SSA blocks The other bug fixes are as follows: - recover xattr node blocks correctly after sudden-power-cut - fix to calculate the maximum number of node ids - enhance to handle many error cases And, there are a bunch of cleanups" * tag 'for-f2fs-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (62 commits) f2fs: fix wrong statistics of inline data f2fs: check the acl's validity before setting f2fs: introduce f2fs_issue_flush to avoid redundant flush issue f2fs: fix to cover io->bio with io_rwsem f2fs: fix error path when fail to read inline data f2fs: use list_for_each_entry{_safe} for simplyfying code f2fs: avoid free slab cache under spinlock f2fs: avoid unneeded lookup when xattr name length is too long f2fs: avoid unnecessary bio submit when wait page writeback f2fs: return -EIO when node id is not matched f2fs: avoid RECLAIM_FS-ON-W warning f2fs: skip unnecessary node writes during fsync f2fs: introduce fi->i_sem to protect fi's info f2fs: change reclaim rate in percentage f2fs: add missing documentation for dir_level f2fs: remove unnecessary threshold f2fs: throttle the memory footprint with a sysfs entry f2fs: avoid to drop nat entries due to the negative nr_shrink f2fs: call f2fs_wait_on_page_writeback instead of native function f2fs: introduce nr_pages_to_write for segment alignment ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-fs-f2fs12
-rw-r--r--Documentation/filesystems/f2fs.txt29
2 files changed, 36 insertions, 5 deletions
diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 32b0809203dd..62dd72522d6e 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -55,3 +55,15 @@ Date: January 2014
Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
Description:
Controls the number of trials to find a victim segment.
+
+What: /sys/fs/f2fs/<disk>/dir_level
+Date: March 2014
+Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+ Controls the directory level for large directory.
+
+What: /sys/fs/f2fs/<disk>/ram_thresh
+Date: March 2014
+Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+ Controls the memory footprint used by f2fs.
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index b8d284975f0f..25311e113e75 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -122,6 +122,10 @@ disable_ext_identify Disable the extension list configured by mkfs, so f2fs
inline_xattr Enable the inline xattrs feature.
inline_data Enable the inline data feature: New created small(<~3.4k)
files can be written into inode block.
+flush_merge Merge concurrent cache_flush commands as much as possible
+ to eliminate redundant command issues. If the underlying
+ device handles the cache_flush command relatively slowly,
+ recommend to enable this option.
================================================================================
DEBUGFS ENTRIES
@@ -169,9 +173,11 @@ Files in /sys/fs/f2fs/<devname>
reclaim_segments This parameter controls the number of prefree
segments to be reclaimed. If the number of prefree
- segments is larger than this number, f2fs tries to
- conduct checkpoint to reclaim the prefree segments
- to free segments. By default, 100 segments, 200MB.
+ segments is larger than the number of segments
+ in the proportion to the percentage over total
+ volume size, f2fs tries to conduct checkpoint to
+ reclaim the prefree segments to free segments.
+ By default, 5% over total # of segments.
max_small_discards This parameter controls the number of discard
commands that consist small blocks less than 2MB.
@@ -195,6 +201,17 @@ Files in /sys/fs/f2fs/<devname>
cleaning operations. The default value is 4096
which covers 8GB block address range.
+ dir_level This parameter controls the directory level to
+ support large directory. If a directory has a
+ number of files, it can reduce the file lookup
+ latency by increasing this dir_level value.
+ Otherwise, it needs to decrease this value to
+ reduce the space overhead. The default value is 0.
+
+ ram_thresh This parameter controls the memory footprint used
+ by free nids and cached nat entries. By default,
+ 10 is set, which indicates 10 MB / 1 GB RAM.
+
================================================================================
USAGE
================================================================================
@@ -444,9 +461,11 @@ The number of blocks and buckets are determined by,
# of blocks in level #n = |
`- 4, Otherwise
- ,- 2^n, if n < MAX_DIR_HASH_DEPTH / 2,
+ ,- 2^ (n + dir_level),
+ | if n < MAX_DIR_HASH_DEPTH / 2,
# of buckets in level #n = |
- `- 2^((MAX_DIR_HASH_DEPTH / 2) - 1), Otherwise
+ `- 2^((MAX_DIR_HASH_DEPTH / 2 + dir_level) - 1),
+ Otherwise
When F2FS finds a file name in a directory, at first a hash value of the file
name is calculated. Then, F2FS scans the hash table in level #0 to find the