Subject: Re: Limiting memory usage of bufcache?
To: Oleg Polianski <>
From: Jukka Marin <>
List: netbsd-users
Date: 08/22/2001 09:20:58
On Wed, Aug 22, 2001 at 06:12:31PM +1200, Oleg Polianski wrote:
>  Actually, if I'm not mistaken, the real reason is not the buffer cache
>  itself but buffer pool that is used for metadata storing. The problem is
>  that it cannot grow dynamically and its size is fixed and calculated during
>  the system startup procedure based on the BUFCACHE option inside `bufinit'
>  kernel subroutine (`/sys/kern/vfs_bio.c'). So, the real I/O thrashing
>  usually is caused by relatively small or, probably, not very effective
>  buffer pool management.

Well, the problem I'd like to fix somehow is that all my processes get
paged out of RAM when I do lots of disk I/O.  After a nightly backup,
switching to another window, de-iconifying Netscape etc. causes lots of
paging.  My mouse pointer freezes, changing focus to a window takes
5...10 seconds etc.. and no "real" disk I/O should occur in these cases,
it's all paging.

(I was making a cd and couldn't switch the windows because I was afraid
of saturating the SCSI disk and corrupting the cd.. It would help if I
had a separate disk for swap, but it would _still_ be paging like crazy.)