Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / Documentation / ABI / testing / sysfs-fs-ext4

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+What:          /sys/fs/ext4/<disk>/mb_stats
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+                Controls whether the multiblock allocator should
+                collect statistics, which are shown during the unmount.
+                1 means to collect statistics, 0 means not to collect
+                statistics
+
+What:          /sys/fs/ext4/<disk>/mb_group_prealloc
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               The multiblock allocator will round up allocation
+               requests to a multiple of this tuning parameter if the
+               stripe size is not set in the ext4 superblock
+
+What:          /sys/fs/ext4/<disk>/mb_max_to_scan
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               The maximum number of extents the multiblock allocator
+               will search to find the best extent
+
+What:          /sys/fs/ext4/<disk>/mb_min_to_scan
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               The minimum number of extents the multiblock allocator
+               will search to find the best extent
+
+What:          /sys/fs/ext4/<disk>/mb_order2_req
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               Tuning parameter which controls the minimum size for 
+               requests (as a power of 2) where the buddy cache is
+               used
+
+What:          /sys/fs/ext4/<disk>/mb_stream_req
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               Files which have fewer blocks than this tunable
+               parameter will have their blocks allocated out of a
+               block group specific preallocation pool, so that small
+               files are packed closely together.  Each large file
+                will have its blocks allocated out of its own unique
+                preallocation pool.
+
+What:          /sys/fs/ext4/<disk>/inode_readahead_blks
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               Tuning parameter which controls the maximum number of
+               inode table blocks that ext4's inode table readahead
+               algorithm will pre-read into the buffer cache
+
+What:          /sys/fs/ext4/<disk>/delayed_allocation_blocks
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               This file is read-only and shows the number of blocks
+               that are dirty in the page cache, but which do not
+               have their location in the filesystem allocated yet.
+
+What:          /sys/fs/ext4/<disk>/lifetime_write_kbytes
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               This file is read-only and shows the number of kilobytes
+               of data that have been written to this filesystem since it was
+               created.
+
+What:          /sys/fs/ext4/<disk>/session_write_kbytes
+Date:          March 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               This file is read-only and shows the number of
+               kilobytes of data that have been written to this
+               filesystem since it was mounted.
+
+What:          /sys/fs/ext4/<disk>/inode_goal
+Date:          June 2008
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               Tuning parameter which (if non-zero) controls the goal
+               inode used by the inode allocator in preference to
+               all other allocation heuristics.  This is intended for
+               debugging use only, and should be 0 on production
+               systems.
+
+What:          /sys/fs/ext4/<disk>/max_writeback_mb_bump
+Date:          September 2009
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               The maximum number of megabytes the writeback code will
+               try to write out before move on to another inode.
+
+What:          /sys/fs/ext4/<disk>/extent_max_zeroout_kb
+Date:          August 2012
+Contact:       "Theodore Ts'o" <tytso@mit.edu>
+Description:
+               The maximum number of kilobytes which will be zeroed
+               out in preference to creating a new uninitialized
+               extent when manipulating an inode's extent tree.  Note
+               that using a larger value will increase the
+               variability of time necessary to complete a random
+               write operation (since a 4k random write might turn
+               into a much larger write due to the zeroout
+               operation).