The previous implementation would iterate over the fid table for
lookup operations, resulting in an operation with O(n) complexity on
the number of open files and poor cache locality -- for every open,
stat, read, write, etc operation.
This change uses a hashtable for this instead, significantly improving
the performance of the 9p filesystem. The runtime of NixOS's simple
installer test, which copies ~122k files totalling ~1.8GiB from 9p,
decreased by a factor of about 10.
Signed-off-by: Linus Heckemann <git@sphalerite.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Greg Kurz <groug@kaod.org>
[CS: - Retain BUG_ON(f->clunked) in get_fid().
- Add TODO comment in clunk_fid(). ]
Message-Id: <20221004104121.713689-1-git@sphalerite.org>
[CS: - Drop unnecessary goto and out: label. ]
Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
f5265c8f91