Re: VM: Found a writable swap-cached page!

Magnus Sjoegren (
Mon, 27 Jul 1998 19:26:19 +0200 (MET DST)

Article: <>
Date: Mon, 27 Jul 1998 10:13:42 -0700
Author: Bill Hawes <>

> > Jul 27 17:32:31 atlas kernel: page=c0234ac0@00065200, found=c0234ac0,
> > count=3
> > Jul 27 17:32:31 atlas kernel: VM: Found a writable swap-cached page!
> > Jul 27 17:32:31 atlas kernel: pte 871047, vma flags 000000fb, page
> > flags 0000028c, count 2
> > Jul 27 17:32:31 atlas kernel: page=c023f530@00065800, found=c023f530,
> > count=3
> Hmm, very interesting. This time the pte present bit is set, so the page is
> really there. The pte flags say dirty/user/rw/present, and the vma flags say
> shared/write/read. Looks like it really shouldn't be swap-cached.
> So the writable swap-cache problem appears to be back in a different form. Can
> you reproduce this easily? We need to figure out what sequence of events leads
> up to this ...


1: Start X and netscape.
2: Switch to console and start any svgalib app, lets say zgv.
View a nice picture.
3: Switch back to netscape and view a webpage. Move around
the page as usual. Wait for syslog to fill.

That's all it takes on my machine (486 DX/2 66, 16MB).
I first saw this while playing with some svgalib code, and I think any
svgalib app will do. Tested with squake, zgv and the examples that
come with svgalib.
Magnus Sjögren <>

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