On 06/17/2017 09:11 AM, Jens Axboe wrote: > On 06/17/2017 09:03 AM, Christoph Hellwig wrote: >> On Sat, Jun 17, 2017 at 08:20:01AM -0600, Jens Axboe wrote: >>> We can certainly go that route. So you'd be fine with allocating 4 >>> streams controller wide by default, and dump the lazy alloc? We can make >>> this depend on the streams module parameter, so people could turn it >>> off, if needed. >> >> We don't even need to allocate the streams - streams are implicitly >> allocated on first use: >> >> "Stream resources that are not allocated for the exclusive use of any >> namespace are available NVM subsystem stream resources as reported in >> NVM Subsystem Streams Available (NSSA) and may be used by any namespace >> that has the Streams Directive enabled and has not been allocated >> exclusive stream resources in response to an Allocate Resources >> operation." >> >> so the only thing you need to do is to enable streams on the namespace, >> or just for whole whole controller using nsid=0xffffffff > > I have two samples here, and I just tested, and both of them want it > assigned with nsid=0xffffffff or they will fail the writes... So I'd say > we're better off ensuring we do allocate them globally. > > For the IO limits, are you sure you want those exposed? SWS is a write > setting, exposing it as io_min may not make sense. For discard, > SWS * SGS * block_size ends up being huge, but I guess at least that > setting does make sense. http://git.kernel.dk/cgit/linux-block/commit/?h=write-stream&id=7c36ee9b7da9fdd26a9663870f49a30ca34d36af I think that should cover all the comments. -- Jens Axboe
