lkml.org 
[lkml]   [2003]   [Jun]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] io stalls (was: -rc7 Re: Linux 2.4.21-rc6)
On Wed, Jun 11, 2003 at 01:42:41PM -0400, Chris Mason wrote:
> + if (q->rq[rw].count >= q->batch_requests) {
> + smp_mb();
> + if (waitqueue_active(&q->wait_for_requests[rw]))
> + wake_up(&q->wait_for_requests[rw]);

in my tree I also changed this to:

wake_up_nr(&q->wait_for_requests[rw], q->rq[rw].count);

otherwise only one waiter will eat the requests, while multiple waiters
can eat requests in parallel instead because we freed not just 1 request
but many of them.

I wonder if my above change is really the right way to implement the
removal of the _exclusive line that went in rc6. However with your patch
the wake_up_nr (or ~equivalent removal of _exclusive wakeup of rc6)
should mostly improve cpu parallelism in smp and while waiting for I/O,
the amount of stuff in the I/O queue and the overall fariness shouldn't
change very significantly with this new completely fair FIFO request
allocator.

Andrea
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:36    [W:0.110 / U:0.384 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site