lkml.org 
[lkml]   [1999]   [Apr]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRE: How to make Linux scale up WRT bandwidth and size?

On 29-Apr-99 Alex Buell wrote:
> On Thu, 29 Apr 1999, Jeremy Fitzhardinge wrote:
>
>> You can't mmap block devices. I don't think avoiding the filesystem
>> will help particularly, though you could avoid some filesystem
>> overhead in the real-time path by preallocating the file.
>
> How come I can mmap() /dev/zero ?

For one, /dev/zero is a character device. It's also specifically designed to be
mmaped, and is very simple to mmap because there's no real underlying device.

There's no fundimental reason why a block device can't be mmaped, but there are
a number of implementation gotchas, pariticularly on 32 bit machines.

J

-
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 13:51    [from the cache]
©2003-2011 Jasper Spaans