Re: 2.6.21-rc2-mm2

Jens Axboe
2007-03-06T11:15:43Z

On Tue, Mar 06 2007, J.A. Magallón wrote:
> On Tue, 6 Mar 2007 00:44:08 -0800, Andrew Morton <akpm@linux-foundation.org> wrote:
>
> >
> > Temporarily at
> >
> > http://userweb.kernel.org/~akpm/2.6.21-rc2-mm2/
> >
>
> Does this include a fix for the NFS problem ?
>
> BTW, I have in my kernel a patch like this below, isn't it needed ?
> Original thread:
>
> http://marc.theaimsgroup.com/?l=linux-kernel&m=117189051227292&w=2
>
> --- a/block/ll_rw_blk.c
> +++ b/block/ll_rw_blk.c
> @@ -2919,14 +2919,14 @@ static int __make_request(request_queue_
> */
> blk_queue_bounce(q, &bio);
>
> + spin_lock_irq(q->queue_lock);
> /*
> * Check if we can merge with the plugged list before grabbing
> * any locks.
> */
> if (!check_plug_merge(q, ioc, bio))
> - goto out;
> + goto out_unlock;
>
> - spin_lock_irq(q->queue_lock);
> el_ret = elv_merge(q, &req, bio);
> if (el_ret == ELEVATOR_BACK_MERGE) {
> if (bio_attempt_back_merge(q, req, bio)) {
> @@ -2984,7 +2984,6 @@ out_unlock:
> list_add_tail(&req->queuelist, &ioc->plugged_list);
> }
>
> -out:
> return 0;
>
> end_io_eopnotsupp:

No it's not, plus andrew didn't include git-block in this release so
you'd have a hard time even applying it. The above patch would also
eliminate 50% of the win of per-process plugging, if you go and grab the
queue lock anyway.

--
Jens Axboe