What: /sys/fs/f2fs/<disk>/gc_max_sleep_time
Date: July 2013
Contact: "Namjae Jeon" <namjae.jeon@samsung.com>
-Description:
- Controls the maximun sleep time for gc_thread. Time
- is in milliseconds.
+Description: Controls the maximum sleep time for gc_thread. Time
+ is in milliseconds.
What: /sys/fs/f2fs/<disk>/gc_min_sleep_time
Date: July 2013
Contact: "Namjae Jeon" <namjae.jeon@samsung.com>
-Description:
- Controls the minimum sleep time for gc_thread. Time
- is in milliseconds.
+Description: Controls the minimum sleep time for gc_thread. Time
+ is in milliseconds.
What: /sys/fs/f2fs/<disk>/gc_no_gc_sleep_time
Date: July 2013
Contact: "Namjae Jeon" <namjae.jeon@samsung.com>
-Description:
- Controls the default sleep time for gc_thread. Time
- is in milliseconds.
+Description: Controls the default sleep time for gc_thread. Time
+ is in milliseconds.
What: /sys/fs/f2fs/<disk>/gc_idle
Date: July 2013
Contact: "Namjae Jeon" <namjae.jeon@samsung.com>
-Description:
- Controls the victim selection policy for garbage collection.
+Description: Controls the victim selection policy for garbage collection.
+ Setting gc_idle = 0(default) will disable this option. Setting
+ gc_idle = 1 will select the Cost Benefit approach & setting
+ gc_idle = 2 will select the greedy approach.
What: /sys/fs/f2fs/<disk>/reclaim_segments
Date: October 2013
Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
- Controls the issue rate of segment discard commands.
-
-What: /sys/fs/f2fs/<disk>/max_blkaddr
+Description: This parameter controls the number of prefree segments to be
+ reclaimed. If the number of prefree 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.
+
+What: /sys/fs/f2fs/<disk>/main_blkaddr
Date: November 2019
Contact: "Ramon Pantin" <pantin@google.com>
Description:
What: /sys/fs/f2fs/<disk>/ipu_policy
Date: November 2013
Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
- Controls the in-place-update policy.
+Description: Controls the in-place-update policy.
+ updates in f2fs. User can set:
+ 0x01: F2FS_IPU_FORCE, 0x02: F2FS_IPU_SSR,
+ 0x04: F2FS_IPU_UTIL, 0x08: F2FS_IPU_SSR_UTIL,
+ 0x10: F2FS_IPU_FSYNC, 0x20: F2FS_IPU_ASYNC,
+ 0x40: F2FS_IPU_NOCACHE.
+ Refer segment.h for details.
What: /sys/fs/f2fs/<disk>/min_ipu_util
Date: November 2013
Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
- Controls the FS utilization condition for the in-place-update
- policies.
+Description: Controls the FS utilization condition for the in-place-update
+ policies. It is used by F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies.
What: /sys/fs/f2fs/<disk>/min_fsync_blocks
Date: September 2014
Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Controls the dirty page count condition for the in-place-update
- policies.
+Description: Controls the dirty page count condition for the in-place-update
+ policies.
What: /sys/fs/f2fs/<disk>/min_seq_blocks
Date: August 2018
Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Controls the dirty page count condition for batched sequential
- writes in ->writepages.
-
+Description: Controls the dirty page count condition for batched sequential
+ writes in writepages.
What: /sys/fs/f2fs/<disk>/min_hot_blocks
Date: March 2017
Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Controls the dirty page count condition for redefining hot data.
+Description: Controls the dirty page count condition for redefining hot data.
What: /sys/fs/f2fs/<disk>/min_ssr_sections
Date: October 2017
Contact: "Chao Yu" <yuchao0@huawei.com>
-Description:
- Controls the fee section threshold to trigger SSR allocation.
+Description: Controls the free section threshold to trigger SSR allocation.
+ If this is large, SSR mode will be enabled early.
What: /sys/fs/f2fs/<disk>/max_small_discards
Date: November 2013
Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
- Controls the issue rate of small discard commands.
+Description: Controls the issue rate of discard commands that consist of small
+ blocks less than 2MB. The candidates to be discarded are cached until
+ checkpoint is triggered, and issued during the checkpoint.
+ By default, it is disabled with 0.
-What: /sys/fs/f2fs/<disk>/discard_granularity
-Date: July 2017
-Contact: "Chao Yu" <yuchao0@huawei.com>
-Description:
- Controls discard granularity of inner discard thread, inner thread
+What: /sys/fs/f2fs/<disk>/discard_granularity
+Date: July 2017
+Contact: "Chao Yu" <yuchao0@huawei.com>
+Description: Controls discard granularity of inner discard thread. Inner thread
will not issue discards with size that is smaller than granularity.
- The unit size is one block, now only support configuring in range
- of [1, 512].
+ The unit size is one block(4KB), now only support configuring
+ in range of [1, 512]. Default value is 4(=16KB).
-What: /sys/fs/f2fs/<disk>/umount_discard_timeout
-Date: January 2019
-Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Set timeout to issue discard commands during umount.
- Default: 5 secs
+What: /sys/fs/f2fs/<disk>/umount_discard_timeout
+Date: January 2019
+Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
+Description: Set timeout to issue discard commands during umount.
+ Default: 5 secs
What: /sys/fs/f2fs/<disk>/max_victim_search
Date: January 2014
Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
-Description:
- Controls the number of trials to find a victim segment.
+Description: Controls the number of trials to find a victim segment
+ when conducting SSR and cleaning operations. The default value
+ is 4096 which covers 8GB block address range.
What: /sys/fs/f2fs/<disk>/migration_granularity
Date: October 2018
Contact: "Chao Yu" <yuchao0@huawei.com>
-Description:
- Controls migration granularity of garbage collection on large
- section, it can let GC move partial segment{s} of one section
- in one GC cycle, so that dispersing heavy overhead GC to
- multiple lightweight one.
+Description: Controls migration granularity of garbage collection on large
+ section, it can let GC move partial segment{s} of one section
+ in one GC cycle, so that dispersing heavy overhead GC to
+ multiple lightweight one.
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.
+Description: Controls the directory level for 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.
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.
+Description: Controls the memory footprint used by free nids and cached
+ nat entries. By default, 1 is set, which indicates
+ 10 MB / 1 GB RAM.
What: /sys/fs/f2fs/<disk>/batched_trim_sections
Date: February 2015
Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Controls the trimming rate in batch mode.
- <deprecated>
+Description: Controls the trimming rate in batch mode.
+ <deprecated>
What: /sys/fs/f2fs/<disk>/cp_interval
Date: October 2015
Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Controls the checkpoint timing.
+Description: Controls the checkpoint timing, set to 60 seconds by default.
What: /sys/fs/f2fs/<disk>/idle_interval
Date: January 2016
Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Controls the idle timing for all paths other than
- discard and gc path.
+Description: Controls the idle timing of system, if there is no FS operation
+ during given interval.
+ Set to 5 seconds by default.
What: /sys/fs/f2fs/<disk>/discard_idle_interval
Date: September 2018
Contact: "Chao Yu" <yuchao0@huawei.com>
Contact: "Sahitya Tummala" <stummala@codeaurora.org>
-Description:
- Controls the idle timing for discard path.
+Description: Controls the idle timing of discard thread given
+ this time interval.
+ Default is 5 secs.
What: /sys/fs/f2fs/<disk>/gc_idle_interval
Date: September 2018
Contact: "Chao Yu" <yuchao0@huawei.com>
Contact: "Sahitya Tummala" <stummala@codeaurora.org>
-Description:
- Controls the idle timing for gc path.
+Description: Controls the idle timing for gc path. Set to 5 seconds by default.
What: /sys/fs/f2fs/<disk>/iostat_enable
Date: August 2017
Contact: "Chao Yu" <yuchao0@huawei.com>
-Description:
- Controls to enable/disable IO stat.
+Description: Controls to enable/disable IO stat.
What: /sys/fs/f2fs/<disk>/ra_nid_pages
Date: October 2015
Contact: "Chao Yu" <chao2.yu@samsung.com>
-Description:
- Controls the count of nid pages to be readaheaded.
+Description: Controls the count of nid pages to be readaheaded.
+ When building free nids, F2FS reads NAT blocks ahead for
+ speed up. Default is 0.
What: /sys/fs/f2fs/<disk>/dirty_nats_ratio
Date: January 2016
Contact: "Chao Yu" <chao2.yu@samsung.com>
-Description:
- Controls dirty nat entries ratio threshold, if current
- ratio exceeds configured threshold, checkpoint will
- be triggered for flushing dirty nat entries.
+Description: Controls dirty nat entries ratio threshold, if current
+ ratio exceeds configured threshold, checkpoint will
+ be triggered for flushing dirty nat entries.
What: /sys/fs/f2fs/<disk>/lifetime_write_kbytes
Date: January 2016
Contact: "Shuoran Liu" <liushuoran@huawei.com>
-Description:
- Shows total written kbytes issued to disk.
+Description: Shows total written kbytes issued to disk.
What: /sys/fs/f2fs/<disk>/features
Date: July 2017
Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Shows all enabled features in current device.
+Description: Shows all enabled features in current device.
What: /sys/fs/f2fs/<disk>/inject_rate
Date: May 2016
Contact: "Sheng Yong" <shengyong1@huawei.com>
-Description:
- Controls the injection rate.
+Description: Controls the injection rate of arbitrary faults.
What: /sys/fs/f2fs/<disk>/inject_type
Date: May 2016
Contact: "Sheng Yong" <shengyong1@huawei.com>
-Description:
- Controls the injection type.
+Description: Controls the injection type of arbitrary faults.
+
+What: /sys/fs/f2fs/<disk>/dirty_segments
+Date: October 2017
+Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
+Description: Shows the number of dirty segments.
What: /sys/fs/f2fs/<disk>/reserved_blocks
Date: June 2017
Contact: "Chao Yu" <yuchao0@huawei.com>
-Description:
- Controls target reserved blocks in system, the threshold
- is soft, it could exceed current available user space.
+Description: Controls target reserved blocks in system, the threshold
+ is soft, it could exceed current available user space.
What: /sys/fs/f2fs/<disk>/current_reserved_blocks
Date: October 2017
Contact: "Yunlong Song" <yunlong.song@huawei.com>
Contact: "Chao Yu" <yuchao0@huawei.com>
-Description:
- Shows current reserved blocks in system, it may be temporarily
- smaller than target_reserved_blocks, but will gradually
- increase to target_reserved_blocks when more free blocks are
- freed by user later.
+Description: Shows current reserved blocks in system, it may be temporarily
+ smaller than target_reserved_blocks, but will gradually
+ increase to target_reserved_blocks when more free blocks are
+ freed by user later.
What: /sys/fs/f2fs/<disk>/gc_urgent
Date: August 2017
Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Do background GC agressively
+Description: Do background GC agressively when set. When gc_urgent = 1,
+ background thread starts to do GC by given gc_urgent_sleep_time
+ interval. It is set to 0 by default.
What: /sys/fs/f2fs/<disk>/gc_urgent_sleep_time
Date: August 2017
Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
-Description:
- Controls sleep time of GC urgent mode
+Description: Controls sleep time of GC urgent mode. Set to 500ms by default.
What: /sys/fs/f2fs/<disk>/readdir_ra
Date: November 2017
Contact: "Sheng Yong" <shengyong1@huawei.com>
-Description:
- Controls readahead inode block in readdir.
+Description: Controls readahead inode block in readdir. Enabled by default.
+
+What: /sys/fs/f2fs/<disk>/gc_pin_file_thresh
+Date: January 2018
+Contact: Jaegeuk Kim <jaegeuk@kernel.org>
+Description: This indicates how many GC can be failed for the pinned
+ file. If it exceeds this, F2FS doesn't guarantee its pinning
+ state. 2048 trials is set by default.
What: /sys/fs/f2fs/<disk>/extension_list
Date: Feburary 2018
Contact: "Chao Yu" <yuchao0@huawei.com>
-Description:
- Used to control configure extension list:
- - Query: cat /sys/fs/f2fs/<disk>/extension_list
- - Add: echo '[h/c]extension' > /sys/fs/f2fs/<disk>/extension_list
- - Del: echo '[h/c]!extension' > /sys/fs/f2fs/<disk>/extension_list
- - [h] means add/del hot file extension
- - [c] means add/del cold file extension
+Description: Used to control configure extension list:
+ - Query: cat /sys/fs/f2fs/<disk>/extension_list
+ - Add: echo '[h/c]extension' > /sys/fs/f2fs/<disk>/extension_list
+ - Del: echo '[h/c]!extension' > /sys/fs/f2fs/<disk>/extension_list
+ - [h] means add/del hot file extension
+ - [c] means add/del cold file extension
What: /sys/fs/f2fs/<disk>/unusable
Date April 2019
Contact: "Daniel Rosenberg" <drosen@google.com>
-Description:
- If checkpoint=disable, it displays the number of blocks that are unusable.
- If checkpoint=enable it displays the enumber of blocks that would be unusable
- if checkpoint=disable were to be set.
+Description: If checkpoint=disable, it displays the number of blocks that
+ are unusable.
+ If checkpoint=enable it displays the enumber of blocks that
+ would be unusable if checkpoint=disable were to be set.
What: /sys/fs/f2fs/<disk>/encoding
Date July 2019
Contact: "Daniel Rosenberg" <drosen@google.com>
-Description:
- Displays name and version of the encoding set for the filesystem.
- If no encoding is set, displays (none)
+Description: Displays name and version of the encoding set for the filesystem.
+ If no encoding is set, displays (none)
Files in /sys/fs/f2fs/<devname>
(see also Documentation/ABI/testing/sysfs-fs-f2fs)
-..............................................................................
- File Content
-
- gc_urgent_sleep_time This parameter controls sleep time for gc_urgent.
- 500 ms is set by default. See above gc_urgent.
-
- gc_min_sleep_time This tuning parameter controls the minimum sleep
- time for the garbage collection thread. Time is
- in milliseconds.
-
- gc_max_sleep_time This tuning parameter controls the maximum sleep
- time for the garbage collection thread. Time is
- in milliseconds.
-
- gc_no_gc_sleep_time This tuning parameter controls the default sleep
- time for the garbage collection thread. Time is
- in milliseconds.
-
- gc_idle This parameter controls the selection of victim
- policy for garbage collection. Setting gc_idle = 0
- (default) will disable this option. Setting
- gc_idle = 1 will select the Cost Benefit approach
- & setting gc_idle = 2 will select the greedy approach.
-
- gc_urgent This parameter controls triggering background GCs
- urgently or not. Setting gc_urgent = 0 [default]
- makes back to default behavior, while if it is set
- to 1, background thread starts to do GC by given
- gc_urgent_sleep_time interval.
-
- reclaim_segments This parameter controls the number of prefree
- segments to be reclaimed. If the number of prefree
- 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.
-
- main_blkaddr This value gives the first block address of
- MAIN area in the partition.
-
- max_small_discards This parameter controls the number of discard
- commands that consist small blocks less than 2MB.
- The candidates to be discarded are cached until
- checkpoint is triggered, and issued during the
- checkpoint. By default, it is disabled with 0.
-
- discard_granularity This parameter controls the granularity of discard
- command size. It will issue discard commands iif
- the size is larger than given granularity. Its
- unit size is 4KB, and 4 (=16KB) is set by default.
- The maximum value is 128 (=512KB).
-
- reserved_blocks This parameter indicates the number of blocks that
- f2fs reserves internally for root.
-
- batched_trim_sections This parameter controls the number of sections
- to be trimmed out in batch mode when FITRIM
- conducts. 32 sections is set by default.
-
- ipu_policy This parameter controls the policy of in-place
- updates in f2fs. User can set:
- 0x01: F2FS_IPU_FORCE, 0x02: F2FS_IPU_SSR,
- 0x04: F2FS_IPU_UTIL, 0x08: F2FS_IPU_SSR_UTIL,
- 0x10: F2FS_IPU_FSYNC, 0x20: F2FS_IPU_ASYNC,
- 0x40: F2FS_IPU_NOCACHE.
- Refer segment.h for details.
-
- min_ipu_util This parameter controls the threshold to trigger
- in-place-updates. The number indicates percentage
- of the filesystem utilization, and used by
- F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies.
-
- min_fsync_blocks This parameter controls the threshold to trigger
- in-place-updates when F2FS_IPU_FSYNC mode is set.
- The number indicates the number of dirty pages
- when fsync needs to flush on its call path. If
- the number is less than this value, it triggers
- in-place-updates.
-
- min_seq_blocks This parameter controls the threshold to serialize
- write IOs issued by multiple threads in parallel.
-
- min_hot_blocks This parameter controls the threshold to allocate
- a hot data log for pending data blocks to write.
-
- min_ssr_sections This parameter adds the threshold when deciding
- SSR block allocation. If this is large, SSR mode
- will be enabled early.
-
- ram_thresh This parameter controls the memory footprint used
- by free nids and cached nat entries. By default,
- 1 is set, which indicates 10 MB / 1 GB RAM.
-
- ra_nid_pages When building free nids, F2FS reads NAT blocks
- ahead for speed up. Default is 0.
-
- dirty_nats_ratio Given dirty ratio of cached nat entries, F2FS
- determines flushing them in background.
-
- max_victim_search This parameter controls the number of trials to
- find a victim segment when conducting SSR and
- cleaning operations. The default value is 4096
- which covers 8GB block address range.
-
- migration_granularity For large-sized sections, F2FS can stop GC given
- this granularity instead of reclaiming entire
- section.
-
- 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.
-
- cp_interval F2FS tries to do checkpoint periodically, 60 secs
- by default.
-
- idle_interval F2FS detects system is idle, if there's no F2FS
- operations during given interval, 5 secs by
- default.
-
- discard_idle_interval F2FS detects the discard thread is idle, given
- time interval. Default is 5 secs.
-
- gc_idle_interval F2FS detects the GC thread is idle, given time
- interval. Default is 5 secs.
-
- umount_discard_timeout When unmounting the disk, F2FS waits for finishing
- queued discard commands which can take huge time.
- This gives time out for it, 5 secs by default.
-
- iostat_enable This controls to enable/disable iostat in F2FS.
-
- readdir_ra This enables/disabled readahead of inode blocks
- in readdir, and default is enabled.
-
- gc_pin_file_thresh This indicates how many GC can be failed for the
- pinned file. If it exceeds this, F2FS doesn't
- guarantee its pinning state. 2048 trials is set
- by default.
-
- extension_list This enables to change extension_list for hot/cold
- files in runtime.
-
- inject_rate This controls injection rate of arbitrary faults.
-
- inject_type This controls injection type of arbitrary faults.
-
- dirty_segments This shows # of dirty segments.
-
- lifetime_write_kbytes This shows # of data written to the disk.
-
- features This shows current features enabled on F2FS.
-
- current_reserved_blocks This shows # of blocks currently reserved.
-
- unusable If checkpoint=disable, this shows the number of
- blocks that are unusable.
- If checkpoint=enable it shows the number of blocks
- that would be unusable if checkpoint=disable were
- to be set.
-
-encoding This shows the encoding used for casefolding.
- If casefolding is not enabled, returns (none)
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USAGE
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