On Fri, Jul 30, 2010 at 05:25:52PM +0400, Vladislav Bolkhovitin wrote: > Sure. It was only a naive example to illustrate my points. But the FS is > still waiting for the requests, so "draining" its "local queue"? Yes, just a much smaller queue in general. To present a typical case, fsync() on a regular file that has a few dirty pages on it using XFS. We use filemap_write_and_wait to write out those few pages and wait for it. And after that we only need to issue a SYNCHRONIZE_CACHE and we'd be done. Right now the draining semantics of the (empty) barrier means we also need to wait for all other I/O in the system to finish, which is rather suboptimal. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
