Christoph Hellwig <hch@xxxxxx> writes: > Given that pmem simply loops over an arbitrarily large bio I think > we also need a threshold for which to allow nowait I/O. While it > won't block for giant I/Os, doing all of them in the submitter > context isn't exactly the idea behind the nowait I/O. > > I'm not really sure what a good theshold would be, though. There's no mention of the latency of the submission side in the documentation for RWF_NOWAIT. The man page says "Do not wait for data which is not immediately available." Data in pmem *is* immediately available. If we wanted to enforce a latency threshold for submission, it would have to be configurable and, ideally, a part of the API. I don't think it's something we should even try to guarantee, though, unless application writers are asking for it. So, I think with the change to return -EAGAIN for writes to poisoned memory, this patch is probably ok. Chaitanya, could you send a v2? Thanks, Jeff
