On Mon, Mar 30, 2015 at 01:26:25PM -0700, Andrew Morton wrote: > > cons: > > d) fincore() is more expensive > > e) fincore() will very occasionally block The above is the killer for Samba. If fincore returns true but when we schedule the pread we block, we're hosed. Once we block, we're done serving clients on the main thread until this returns. That can cause unpredictable response times which can cause client timeouts. A fincore+pread solution that blocks is simply unsafe to use for us. We'll have to stay with the threadpool :-(. > And I don't believe that e) will be a problem in the real world. It's > a significant increase in worst-case latency and a negligible increase > in average latency. I've asked at least three times for someone to > explain why this is unacceptable and no explanation has been provided. See above. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
