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e95382834c
Currently read_extent_buffer_pages skips pages that are already uptodate when reading in an extent_buffer. While this reduces the amount of data read, it increases the number of I/O operations as we now need to do multiple I/Os when reading an extent buffer with one or more uptodate pages in the middle of it. On any modern storage device, be that hard drives or SSDs this actually decreases I/O performance. Fortunately this case is pretty rare as the pages are always initially read together and then aged the same way. Besides simplifying the code a bit as-is this will allow for major simplifications to the I/O completion handler later on. Note that the case where all pages are uptodate is still handled by an optimized fast path that does not read any data from disk. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.