Re: ll_rw_blk.c fails to merge requests. Help!

From: Giuliano Pochini (pochini@denise.shiny.it)
Date: Sat Aug 26 2000 - 17:24:49 EST


> > MF means: failed to merge block xxx length yyy
> > REQ: got new request entry
> > NOREQ: failed to get new request entry and go to sleep
> > ADD: block xxx length yyy added (not merged) to the queue

> Please try the following (totally untested I'm afraid) patch and see
> if it makes a difference.
> It basically retries the merge after waiting for a request, and then
> either releases the request if the merge was successful, or uses that
> request to add the bh to the queue.

It works much better, but it still fails to merge blocks. The following
is a report of write requests directly from the scsi driver:
(I'm now using -test7)

Aug 26 18:09:19 Jay kernel: W 914680 252
Aug 26 18:09:19 Jay kernel: W 914932 8
Aug 26 18:09:19 Jay kernel: W 851976 4
Aug 26 18:09:19 Jay kernel: W 914940 252
Aug 26 18:09:19 Jay kernel: W 915192 4
Aug 26 18:09:19 Jay kernel: W 915196 252
Aug 26 18:09:19 Jay kernel: W 915448 12
Aug 26 18:09:19 Jay kernel: W 915460 252
Aug 26 18:09:19 Jay kernel: W 915712 4
Aug 26 18:09:19 Jay kernel: W 915716 252
Aug 26 18:09:19 Jay kernel: W 915968 12
Aug 26 18:09:19 Jay kernel: W 915980 252
Aug 26 18:09:19 Jay kernel: W 916232 4
Aug 26 18:09:19 Jay kernel: W 916236 252
Aug 26 18:09:19 Jay kernel: W 916488 12
Aug 26 18:09:19 Jay kernel: W 916500 252
Aug 26 18:09:19 Jay kernel: W 916752 4
Aug 26 18:09:20 Jay kernel: W 916756 252
Aug 26 18:09:20 Jay kernel: W 917008 12
Aug 26 18:09:20 Jay kernel: W 917020 252
Aug 26 18:09:20 Jay kernel: W 917272 232
Aug 26 18:09:20 Jay kernel: W 917512 4
Aug 26 18:09:20 Jay kernel: W 926504 4
Aug 26 18:09:20 Jay kernel: W 926508 252

> It also contains some (fairly ugly) code inside #ifdef
> STRICT_REQUEST_ORDERING which should encourage a strict ordering for
> threads to get the request structures they are waiting for.

It makes no difference.

Bye.

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



This archive was generated by hypermail 2b29 : Thu Aug 31 2000 - 21:00:18 EST