Re: [PATCHSET block#for-2.6.36-post] block: replace barrier with sequenced flush

From: Christoph Hellwig
Date: Mon Aug 23 2010 - 10:09:02 EST


On Mon, Aug 23, 2010 at 04:01:15PM +0200, Jens Axboe wrote:
> The problem purely exists on arrays that report write back cache enabled
> AND don't implement SYNC_CACHE as a noop. Do any of them exist, or are
> they purely urban legend?

I haven't seen it. I don't care particularly about this case, but once
it a while people want to disable flushing for testing or because they
really don't care.

What about adding a sysfs attribue to every request_queue that allows
disabling the cache flushing feature? Compared to the barrier option
this controls the feature at the right level and makes it available
to everyone instead of beeing duplicated. After a while we can then
simply ignore the barrier/nobarrier options.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/