Subject: Re: kern/15232: ffs_sync writes out read-only pages to disk
To: None <email@example.com>
From: David Laight <firstname.lastname@example.org>
Date: 01/13/2002 11:16:25
> >Number: 15232
> >Category: kern
> >Synopsis: ffs_sync writes out read-only pages to disk
> I spent some time trying to figure out why my ibook's disk
> would not spin down when idle after I had been using the system for a
> while. Eventually, I discovered that our ffs_sync routine flushes out
> a vnode if vp->v_uobj.uo_pages is non-zero. Since this is true when
> an executable is mapped read-only, i found that my executables and
> shared libraries were constantly being written out to disk.
Am I being naive?
Surely there is a 'page modified' bit - and the write should only
if it is modified?
There should probably be a check at this level against writing back
modified pages that were mapper readonly as well.