Messages in this thread | | | Date | Thu, 26 Mar 2009 14:47:34 +0000 (GMT) | From | Hugh Dickins <> | Subject | Re: Linux 2.6.29 |
| |
On Thu, 26 Mar 2009, Jens Axboe wrote: > On Wed, Mar 25 2009, Hugh Dickins wrote: > > > > Tangential question, but am I right in thinking that BIO_RW_BARRIER > > similarly bars across all partitions, whereas its WRITE_BARRIER and > > DISCARD_BARRIER users would actually prefer it to apply to just one? > > All the barriers refer to just that range which the barrier itself > references.
Ah, thank you: then I had a fundamental misunderstanding of them, and need to go away and work that out some more.
Though I didn't read it before asking, doesn't the I/O Barriers section of Documentation/block/biodoc.txt give a very different impression?
> The problem with the full device flushes is implementation > on the hardware side, since we can't do small range flushes. So it's not > as-designed, but rather the best we can do...
Right, that part of it I did get.
Hugh
| |