On Tue, 16 Oct 2018 08:46:06 +0100 Mel Gorman <mgorman@xxxxxxx> wrote: > On Mon, Oct 15, 2018 at 03:44:59PM -0700, Andrew Morton wrote: > > On Mon, 15 Oct 2018 15:30:17 -0700 (PDT) David Rientjes <rientjes@xxxxxxxxxx> wrote: > > > > > At the risk of beating a dead horse that has already been beaten, what are > > > the plans for this patch when the merge window opens? > > > > I'll hold onto it until we've settled on something. Worst case, > > Andrea's original is easily backportable. > > > > I consider this to be an unfortunate outcome. On the one hand, we have a > problem that three people can trivially reproduce with known test cases > and a patch shown to resolve the problem. Two of those three people work > on distributions that are exposed to a large number of users. On the > other, we have a problem that requires the system to be in a specific > state and an unknown workload that suffers badly from the remote access > penalties with a patch that has review concerns and has not been proven > to resolve the trivial cases. In the case of distributions, the first > patch addresses concerns with a common workload where on the other hand > we have an internal workload of a single company that is affected -- > which indirectly affects many users admittedly but only one entity directly. > > At the absolute minimum, a test case for the "system fragmentation incurs > access penalties for a workload" scenario that could both replicate the > fragmentation and demonstrate the problem should have been available before > the patch was rejected. With the test case, there would be a chance that > others could analyse the problem and prototype some fixes. The test case > was requested in the thread and never produced so even if someone were to > prototype fixes, it would be dependant on a third party to test and produce > data which is a time-consuming loop. Instead, we are more or less in limbo. > OK, thanks. But we're OK holding off for a few weeks, yes? If we do that we'll still make it into 4.19.1. Am reluctant to merge this while discussion, testing and possibly more development are ongoing.
