Subject: Re: UVM/other problems for desktop users in current?
To: Manuel Bouyer <>
From: John Franklin <>
List: current-users
Date: 12/23/2002 19:43:29
On Monday, Dec 23, 2002, at 12:21 US/Eastern, Manuel Bouyer wrote:
> On Fri, Dec 20, 2002 at 09:27:43AM -0500, Gary Thorpe wrote:
>> So what exaqctly is the point of UBC if you have to manually =
>> how much buffer cache your system will use? Is file system I/O and
>> device buffering now unified, but not much else (and was this this=20
>> case
>> before anyway)? How is this different from the compile-time setting
>> used in 1.5?
> The buffer memory is still used to buffer filesystem metadata. For=20
> example,
> on a filesystem with lots of small files you may want to bump the
> buffer cache size to be able to buffer more directories.

Is there any technical reason why we have to pre-allocate buffer cache?=20=

  Can't it be allocated on demand by UVM and/or the VFS and/or the=20
specific FS?  I understand there may be some deadlock issues, but the=20
kernel can allocate a small number of pages for critical needs such as=20=


John Franklin
ICBM: 35=B043'56"N 78=B053'27"W