On Thu, 2006-03-02 at 18:43 -0600, Amanda Kirkconnell wrote:
> This mod introduces multi-level in-core file extent functionality,
> building upon the new layout introduced in mod xfs-linux:xfs-kern:207390a.
>
> The new multi-level extent allocations are only required for heavily
> fragmented files, so the old-style linear extent list is used on files
> until the extents reach a pre-determined size of 4k. 4k buffers are
> used because this is the system page size on Linux i386 and systems
> with larger page sizes don't seem to gain much, if anything, by using
> their native page size as the extent buffer size. Also, using 4k extent
> buffers everywhere provides a consistent interface for CXFS across
> different platforms.
So does this aim to speed up file offset to extent lookup on heavily
fragmented files when we have all (most) of extents in core?
And also to not require such large contiguous kernel memory allocations
for lots of extents? (e.g. 10,000 extents)
I'm assuming this is more noticeable with CXFS? i.e. less stuff over the
wire when only caring about small parts of highly fragmented file.
--
Stewart Smith (stewart@xxxxxxxxxxxxxxxx)
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