Re: journaling & VM (was: Re: reiserfs being part of the kernel: it's not just the code)

Hi,

On Tue, Jun 06, 2000 at 08:06:38PM -0300, Rik van Riel wrote:

quoted

journaling itself, but the transactional requirements which are
the problem --- basically the VM cannot do _anything_ about
individual pages which are pinned by a transaction, but rather
we need a way to trigger a filesystem flush, AND to prevent more
dirtying of pages by the filesystem (these are two distinct
problems), or we just lock up under load on lower memory boxes.

This is especially tricky in the case of a large mmap()ed
file. We'll have to restrict the maximum number of read-write
mapped pages from such a file in order to keep the system
stable...

We need to restrict *all* pinned pages.  That includes writable
pages on a transactional filesystem, but also includes metadata
being used as part of an existing transaction, as well as any
potential metadata which *might* be used in the future by that
transaction.

Indeed we need this. Since I seem to be coordinating the VM
changes at the moment anyway, I'd love to work together with
the journaling folks on solving this problem...

OK, I'll look up the old writeups I did with Chris about this.

Cheers,
 Stephen
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