Messages in this thread | | | Date | Mon, 4 Mar 2002 18:09:38 +0000 | From | "Stephen C. Tweedie" <> | Subject | Re: [PATCH] 2.4.x write barriers (updated for ext3) |
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Hi,
On Mon, Mar 04, 2002 at 11:35:24AM -0600, James Bottomley wrote:
> Have there been any published comparisons of a write barrier implementation > verses something like the McKusick soft update idea
Soft updates are just another mechanism of doing ordered writes. If the disk IO subsystem is lying about write ordering or is doing unexpected writeback caching, soft updates are no more of a cure than journaling.
> or even just > multi-threaded back end completion of the transactions?
ext3 already does the on-disk transaction complete asynchronously within a separate kjournald thread, independent of writeback IO going on in the VM's own writeback threads. Given that it is kernel code given full access to the kernel's internal lazy IO completion mechanisms, I'm not sure that it can usefully be given any more threading. I think the reiserfs situation is similar.
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