On Thu, Oct 17, 2019 at 9:32 AM Dave Hansen <dave.hansen@xxxxxxxxx> wrote: > > On 10/17/19 9:01 AM, Suleiman Souhlal wrote: > > One problem that came up is that if you get into direct reclaim, > > because persistent memory can have pretty low write throughput, you > > can end up stalling users for a pretty long time while migrating > > pages. > > Basically, you're saying that memory load spikes turn into latency spikes? > > FWIW, we have been benchmarking this sucker with benchmarks that claim > to care about latency. In general, compared to DRAM, we do see worse > latency, but nothing catastrophic yet. I'd be interested if you have > any workloads that act as reasonable proxies for your latency requirements. > > > Because of that, we moved to a solution based on the proactive reclaim > > of idle pages, that was presented at LSFMM earlier this year: > > https://lwn.net/Articles/787611/ . > > I saw the presentation. The feedback in the room as I remember it was > that proactive reclaim essentially replaced the existing reclaim > mechanism, to which the audience was not receptive. Have folks opinions > changed on that, or are you looking for other solutions? > I am currently working on a solution which shares the mechanisms between regular and proactive reclaim. The interested users/admins can setup proactive reclaim otherwise the regular reclaim will work on low memory. I will have something in one/two months and will post the patches. Shakeel
