lkml.org 
[lkml]   [1999]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: disk head scheduling
Hi,

On Thu, 18 Mar 1999 20:50:36 +0100 (CET), Ingo Molnar
<mingo@chiara.csoma.elte.hu> said:

>> Another point is that IN_ORDER seems to be called only for two requests
>> on the same device, so no idea why it compares the device numbers.

To distinguish between partition access on the same major device.

> no, all requests (for all devices) are in a single 'queue'. (Per-major
> device queues is candidate 2.3 feature, it's really simple)

No, each major has its own queue, defined either by the
blkdev[major].queue() strategy function or by
blkdev[major].current_request. As far as IN_ORDER is concerned, it will
only ever look at one such queue at a time.

You're probably thinking of the global request array "all_requests", but
that is just a global, static pool from which we allocate request
structs. Active requests are most definitely kept on separate queues
for each device.

--Stephen

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

\
 
 \ /
  Last update: 2005-03-22 13:50    [W:0.325 / U:0.216 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site