chunkqueue_chunk_file_view()
reduces size of struct chunk
use mmap with mod_deflate libdeflate, if mmap available,
even when lighttpd not built with --enable-mmap
avoid using mmap on temp files in chunkqueue (c->file.is_temp)
since pread() with a reasonable block size is typically as fast
or faster than mmap on files read sequentially and used only once,
especially when writing results to limited-size socket buffers
(and lighttpd temp files are, in most cases, by default about 1 MB)
(Exception: sometimes mmap is used for convenience or to fulfill
a requirement, e.g. one-shot libdeflate in mod_deflate)
(There are many factors which influence speed of mmap versus pread,
so this should not be construed as generic usage advice.)
Glenn Strauss
Stefan Bühler
Jan Kneschke