Re: VM subsystem bug in 2.4.0 ?

Stephen C. Tweedie
2001-01-09T15:36:04Z

Hi,

On Tue, Jan 09, 2001 at 03:53:55PM +0100, Christoph Rohland wrote:
>
> On Tue, 9 Jan 2001, Stephen C. Tweedie wrote:
> > But again, how do you clear the bit? Locking is a per-vma property,
> > not per-page. I can mmap a file twice and mlock just one of the
> > mappings. If you get a munlock(), how are you to know how many
> > other locked mappings still exist?
>
> It's worse: The issue we are talking about is SYSV IPC_LOCK.

The issue is locked VA pages. SysV is just one of the ways in which
it can happen: the solution has got to address both that and
mlock()/mlockall().

> This is a
> per segment thing. A user can (un)lock a segment at any time. But we
> do not have the references to the vmas attached to the segemnts

Why not? Won't the address space mmap* lists give you this?

--Stephen