On Tue, 2016-02-16 at 15:21 -0600, Scott Wood wrote: > On Thu, 2016-02-11 at 17:16 +0100, Christophe Leroy wrote:
> > This patch provides VIRT_CPU_ACCOUTING to PPC32 architecture. > > PPC32 doesn't have the PACA structure, so we use the task_info > > structure to store the accounting data. > > > > In order to reuse on PPC32 the PPC64 functions, all u64 data has > > been replaced by 'unsigned long' so that it is u32 on PPC32 and > > u64 on PPC64 > > > > Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr> > > --- > > Changes in v3: unlike previous version of the patch that was inspired > > from IA64 architecture, this new version tries to reuse as much as > > possible the PPC64 implementation. > > > > PPC32 doesn't have PACA and past discusion on v2 version has shown > > that it is not worth implementing a PACA in PPC32 architecture > > (see below benh opinion) > > > > benh: PACA is actually a data structure and you really really don't want it > > on ppc32 :-) Having a register point to current works, having a register > > point to per-cpu data instead works too (ie, change what we do today), > > but don't introduce a PACA *please* :-) > > And Ben never replied to my reply at the time: > > "What is special about 64-bit that warrants doing things differently from 32 > -bit? Nothing. It's just historical cruft. But we're not realistically going to get rid of it anytime soon on 64-bit. > What is the difference between PACA and "per-cpu data", other than the > obscure name?" Not much. The pacas are allocated differently to per-cpu data, they're available earlier in boot etc. What we'd like is to have r13 point to the per-cpu data area, and then the contents of the paca could just be regular per-cpu data. But like I said above that's a big change. cheers _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
