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ext4: Add multi block allocator for ext4

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Signed-off-by: Alex Tomas <alex@clusterfs.com>
Signed-off-by: Andreas Dilger <adilger@clusterfs.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Alex Tomas
2008-01-29 00:19:52 -05:00
committed by Theodore Ts'o
parent 1988b51e47
commit c9de560ded
13 changed files with 4900 additions and 38 deletions
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10
Documentation/filesystems/ext4.txt
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@@ -86,9 +86,11 @@ Alex is working on a new set of patches right now.
When mounting an ext4 filesystem, the following option are accepted:
(*) == default
extents ext4 will use extents to address file data. The
extents (*) ext4 will use extents to address file data. The
file system will no longer be mountable by ext3.
noextents ext4 will not use extents for newly created files
journal_checksum Enable checksumming of the journal transactions.
This will allow the recovery code in e2fsck and the
kernel to detect corruption in the kernel. It is a
@@ -206,6 +208,12 @@ nobh (a) cache disk block mapping information
"nobh" option tries to avoid associating buffer
heads (supported only for "writeback" mode).
mballoc (*) Use the multiple block allocator for block allocation
nomballoc disabled multiple block allocator for block allocation.
stripe=n Number of filesystem blocks that mballoc will try
to use for allocation size and alignment. For RAID5/6
systems this should be the number of data
disks * RAID chunk size in file system blocks.
Data Mode
---------

39
Documentation/filesystems/proc.txt
View File

@@ -857,6 +857,45 @@ CPUs.
The "procs_blocked" line gives the number of processes currently blocked,
waiting for I/O to complete.
1.9 Ext4 file system parameters
------------------------------
Ext4 file system have one directory per partition under /proc/fs/ext4/
# ls /proc/fs/ext4/hdc/
group_prealloc max_to_scan mb_groups mb_history min_to_scan order2_req
stats stream_req
mb_groups:
This file gives the details of mutiblock allocator buddy cache of free blocks
mb_history:
Multiblock allocation history.
stats:
This file indicate whether the multiblock allocator should start collecting
statistics. The statistics are shown during unmount
group_prealloc:
The multiblock allocator normalize the block allocation request to
group_prealloc filesystem blocks if we don't have strip value set.
The stripe value can be specified at mount time or during mke2fs.
max_to_scan:
How long multiblock allocator can look for a best extent (in found extents)
min_to_scan:
How long multiblock allocator must look for a best extent
order2_req:
Multiblock allocator use 2^N search using buddies only for requests greater
than or equal to order2_req. The request size is specfied in file system
blocks. A value of 2 indicate only if the requests are greater than or equal
to 4 blocks.
stream_req:
Files smaller than stream_req are served by the stream allocator, whose
purpose is to pack requests as close each to other as possible to
produce smooth I/O traffic. Avalue of 16 indicate that file smaller than 16
filesystem block size will use group based preallocation.
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Summary