Re: VM subsystem bug in 2.4.0 ?

Christoph Rohland
2001-01-09T15:45:55Z

Hi Stephen,

On Tue, 9 Jan 2001, Stephen C. Tweedie wrote:
> On Tue, Jan 09, 2001 at 03:53:55PM +0100, Christoph Rohland wrote:
>> 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().

AFAIU mlock'ed pages would never get deactivated since the ptes do not
get dropped.

>> 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?

OK. We could go from shmid_kernel->file->dentry->inode->mapping
We had to scan all mappings for pages in the page tables and in the
page cache. Doesn't look really nice :-(

Greetings
Christoph