"Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> writes:
> Joonsoo Kim <iamjoonsoo....@lge.com> writes: > >> On Tue, Aug 30, 2016 at 04:09:37PM +0530, Aneesh Kumar K.V wrote: >>> Joonsoo Kim <js1...@gmail.com> writes: >>> >>> > 2016-08-29 18:27 GMT+09:00 Aneesh Kumar K.V >>> > <aneesh.ku...@linux.vnet.ibm.com>: >>> >> js1...@gmail.com writes: >>> >> >>> >>> From: Joonsoo Kim <iamjoonsoo....@lge.com> >>> >>> >>> >>> Hello, >>> >>> >>> >>> Changes from v4 >>> >>> o Rebase on next-20160825 >>> >>> o Add general fix patch for lowmem reserve >>> >>> o Fix lowmem reserve ratio >>> >>> o Fix zone span optimizaion per Vlastimil >>> >>> o Fix pageset initialization >>> >>> o Change invocation timing on cma_init_reserved_areas() >>> >> >>> >> I don't see much information regarding how we interleave between >>> >> ZONE_CMA and other zones for movable allocation. Is that explained in >>> >> any of the patch ? The fair zone allocator got removed by >>> >> e6cbd7f2efb433d717af72aa8510a9db6f7a7e05 >>> > >>> > Interleaving would not work since the fair zone allocator policy is >>> > removed. >>> > I don't think that it's a big problem because it is just matter of >>> > timing to fill >>> > up the memory. Eventually, memory on ZONE_CMA will be fully used in >>> > any case. >>> >>> Does that mean a CMA allocation will now be slower because in most case we >>> will need to reclaim ? The zone list will now have ZONE_CMA in the >>> beginning right ? >> >> ZONE_CMA will be used first but I don't think that CMA allocation will >> be slower. In most case, memory would be fully used (usually >> by page cache). So, we need reclaim or migration in any case. > > Considering that the upstream kernel doesn't allow migration of THP > pages, this would mean that migrate will fail in most case if we have > THP enabled and the THP allocation request got satisfied via ZONE_CMA. > Isn't that going to be a problem ? > Even though we have the issues of migration failures due to pinned and THP pages in ZONE_CMA, overall the code is simpler. IMHO we should get this upstream now and work on solving those issues later. You can add for the complete series. Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> -aneesh
