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Diffstat (limited to 'Documentation/filesystems/proc.txt')
-rw-r--r-- | Documentation/filesystems/proc.txt | 70 |
1 files changed, 33 insertions, 37 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index f566ad9bcb7b..d9ac9706735b 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt | |||
@@ -923,45 +923,41 @@ CPUs. | |||
923 | The "procs_blocked" line gives the number of processes currently blocked, | 923 | The "procs_blocked" line gives the number of processes currently blocked, |
924 | waiting for I/O to complete. | 924 | waiting for I/O to complete. |
925 | 925 | ||
926 | |||
926 | 1.9 Ext4 file system parameters | 927 | 1.9 Ext4 file system parameters |
927 | ------------------------------ | 928 | ------------------------------ |
928 | Ext4 file system have one directory per partition under /proc/fs/ext4/ | 929 | |
929 | # ls /proc/fs/ext4/hdc/ | 930 | Information about mounted ext4 file systems can be found in |
930 | group_prealloc max_to_scan mb_groups mb_history min_to_scan order2_req | 931 | /proc/fs/ext4. Each mounted filesystem will have a directory in |
931 | stats stream_req | 932 | /proc/fs/ext4 based on its device name (i.e., /proc/fs/ext4/hdc or |
932 | 933 | /proc/fs/ext4/dm-0). The files in each per-device directory are shown | |
933 | mb_groups: | 934 | in Table 1-10, below. |
934 | This file gives the details of multiblock allocator buddy cache of free blocks | 935 | |
935 | 936 | Table 1-10: Files in /proc/fs/ext4/<devname> | |
936 | mb_history: | 937 | .............................................................................. |
937 | Multiblock allocation history. | 938 | File Content |
938 | 939 | mb_groups details of multiblock allocator buddy cache of free blocks | |
939 | stats: | 940 | mb_history multiblock allocation history |
940 | This file indicate whether the multiblock allocator should start collecting | 941 | stats controls whether the multiblock allocator should start |
941 | statistics. The statistics are shown during unmount | 942 | collecting statistics, which are shown during the unmount |
942 | 943 | group_prealloc the multiblock allocator will round up allocation | |
943 | group_prealloc: | 944 | requests to a multiple of this tuning parameter if the |
944 | The multiblock allocator normalize the block allocation request to | 945 | stripe size is not set in the ext4 superblock |
945 | group_prealloc filesystem blocks if we don't have strip value set. | 946 | max_to_scan The maximum number of extents the multiblock allocator |
946 | The stripe value can be specified at mount time or during mke2fs. | 947 | will search to find the best extent |
947 | 948 | min_to_scan The minimum number of extents the multiblock allocator | |
948 | max_to_scan: | 949 | will search to find the best extent |
949 | How long multiblock allocator can look for a best extent (in found extents) | 950 | order2_req Tuning parameter which controls the minimum size for |
950 | 951 | requests (as a power of 2) where the buddy cache is | |
951 | min_to_scan: | 952 | used |
952 | How long multiblock allocator must look for a best extent | 953 | stream_req Files which have fewer blocks than this tunable |
953 | 954 | parameter will have their blocks allocated out of a | |
954 | order2_req: | 955 | block group specific preallocation pool, so that small |
955 | Multiblock allocator use 2^N search using buddies only for requests greater | 956 | files are packed closely together. Each large file |
956 | than or equal to order2_req. The request size is specfied in file system | 957 | will have its blocks allocated out of its own unique |
957 | blocks. A value of 2 indicate only if the requests are greater than or equal | 958 | preallocation pool. |
958 | to 4 blocks. | 959 | .............................................................................. |
959 | 960 | ||
960 | stream_req: | ||
961 | Files smaller than stream_req are served by the stream allocator, whose | ||
962 | purpose is to pack requests as close each to other as possible to | ||
963 | produce smooth I/O traffic. Avalue of 16 indicate that file smaller than 16 | ||
964 | filesystem block size will use group based preallocation. | ||
965 | 961 | ||
966 | ------------------------------------------------------------------------------ | 962 | ------------------------------------------------------------------------------ |
967 | Summary | 963 | Summary |