lkml.org 
[lkml]   [1997]   [Jun]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: Loop Encryption
Date
> P.S. Is it me, or is get_request() in drivers/block/ll_rw_blk.c
> particularly complex for the simple job it does (with interrupts
> disabled I might add)?

I just rewrote it. It now allocates WRITEs from one end, and READs
from the other. It is faster - on average, fewer requests are searched.
Is is also more fair - READs and WRITEs get clustered at the ends
of the all_requests array, so a READ (higher priority) is less likely
to fill up a WRITE (lower priority) slot, except when the system is
busy with lots of requests.

I also rewrote get_request_wait() and eliminated __get_request_wait().
The new code has generic support for handling drivers (like loop)
that require multiple requests to complete a single request. They
are put to sleep BEFORE THEY CAN START until there are enough free
requests - the old code could only do this for single requests.

I've been punishing the code for over 4 hours continuously now,
by moving an 8 MB file to/from a deeply looped (XOR) file
(mounted=loop7->loop6->loop5->loop4->loop3->loop2->loop1->loop0->file)
and syncing. Works wonderfully.

The source is not yet ready for prime time (I know I can make it better),
but it is available directly from me as part of my modular loop driver
patch (which now supports kerneld too!).

After this, I attack the buffer cache (particularly bdflush) to improve
its loop driver support.

--
Andrew E. Mileski mailto:aem@netcom.ca
Linux Plug-and-Play Hardware Support http://www.redhat.com/linux-info/pnp/
XFree86 Matrox Team http://www.bf.rmit.edu.au/~ajv/xf86-matrox.html
Ottawa-Carleton Linux User's Group (OCLUG) http://www.storm.ca/~linux/

\
 
 \ /
  Last update: 2005-03-22 13:39    [from the cache]
©2003-2011 Jasper Spaans