On Wed, Nov 12, 2014 at 06:41:30PM +0800, Ming Liu wrote: > On 11/12/2014 04:51 PM, Herbert Xu wrote: > >On Wed, Nov 12, 2014 at 09:41:38AM +0100, Steffen Klassert wrote: > >>Can't we just use cryptd unconditionally to fix this reordering problem? > >I think the idea is that most of the time cryptd isn't required > >so we want to stick with direct processing to lower latency. > > > >I think the simplest fix would be to punt to cryptd as long as > >there are cryptd requests queued. > I've tried that method when I started to think about the fix, but it > will cause 2 other issues per test while resolving the reordering > one, as follows: > 1 The work queue can not handle so many packets when the traffic is > very high(over 200M/S), and it would drop most of them when the > queue length is beyond CRYPTD_MAX_CPU_QLEN. That's why I've proposed to adjust CRYPTD_MAX_CPU_QLEN in my other mail. But anyway, it still does not fix the reorder problem completely. We still have a problem if subsequent algorithms run asynchronously or if we get interrupted while we are processing the last request from the queue. I think we have only two options, either processing all calls directly or use cryptd unconditionally. Mixing direct and asynchronous calls will lead to problems. If we don't want to use cryptd unconditionally, we could use direct calls for all requests. If the fpu is not usable, we maybe could fallback to an algorithm that does not need the fpu, such as aes-generic. -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
