On Thu, Nov 05, 2009 at 09:39:36AM +0800, Wu Zhangjin wrote: > > > > We have other systems where 32-bit kernel support is just remarkably ugly. > > > > We've dropped 32-bit support for the SGI IP32 aka O2 - nobody seems to even > > > > have really noticed that. The Sibyte systems would be good candidates to do > > > > the same as accesses to outside the 32-bit address space are needed very > > > > frequently. > > > > > > > > > > So, we really remove the 32bit support? > > > > > > 1312 config CPU_LOONGSON2 > > > 1313 bool > > > 1314 select CPU_SUPPORTS_32BIT_KERNEL --> remove it? > > > 1315 select CPU_SUPPORTS_64BIT_KERNEL > > > 1316 select CPU_SUPPORTS_HIGHMEM > > > > > > If you all agree, I will send a new patch to remove the above line and > > > resend the corresponding patches without 32bit support, and removed the > > > relative CONFIG_64BIT lines in the patches too. > > > > If you need highmem with 32-bit (and with Loongson systems I assume that > > virtually all systems will have enough RAM to require that) then you're > > almost certainly better off going 64-bit. Highmem takes a performance toll > > which for some workloads can be very significant. And while highmem won't > > go away any time soon it's nothing kernel performance is being tuned for, > > so it's only going to get worse into the future so I'd not waste time on > > highmem unless I have to. > > > > What I have mentioned: "perhaps some guys need the 32bit version" here > means, perhaps some embedded systems without enough memory and enough > storage space may need the 32bit version, they not need highmem and > also, the 32bit version will save some storage space for them. and I > have used the 32bit version on my box and notebook(of course, only for > experiments), no obvious problems. > > Reserve the 32bit version as an choice and select 64bit by default in > the default config file? No problem - I was just expressing my expressing my experiences on the usefulness of supporting both settings. One usually tends up favored, the other little used. Ralf
