Subject: re: kern/7511: madvise(2) is not implemented
To: Jason Thorpe <email@example.com>
From: matthew green <firstname.lastname@example.org>
Date: 05/03/1999 12:18:50
> write an application that uses MADV_SEQUENTIAL, expecting the VM system
> to deactivate pages after you have looked at them and notice that this
> does not appear to happen. scratch head and read the source (mmm, source)
> and realise that while the code does advice you can't change it.
MADV_SEQUENTIAL doesn't do this. SEQUENTIAL is intended to cause a clustered
pagein of page N -> N + M (whatever a convenient cluster size is), so that
faults aren't taken on the subsequent pages.
yes, it does this...but it also deactives pages behind -- if i'm going
to be sequentially accessing some memory, i don't need it after i have
read it, right? this is what MADV_SEQUENTIAL does in NetBSD currently
except for the fact that you have no way to set it (other than Evil