Hi, The patch below adds sparsemem support for ARC.
It's really a hack for now, as I'll need to sort out the generic MM bits to allow creation of ZONE_HIGHMEM below ZONE_NORMAL on the same node. The eventual intention is to completely replace DISCONTIGMEM with SPARSEMEM provided the latter is at least as efficient. I don't have access to ARC hardware I could only check the compilation and the differences in the resulting vmlinux size. Apparently, I've managed to have all three memory models buildable, at least with defconfig + override for the memory model selection. With the current changes sparsemem build creates a larger kernel, especially with CONFIG_ARC_HAS_PAE40=y: $ size -x discontigmem/vmlinux sparsemem/vmlinux text data bss dec hex filename 0x348c5e 0xec5dc 0x3b658 4655250 470892 discontigmem/vmlinux 0x3490cf 0xecde4 0x3bde0 4660371 471c93 sparsemem/vmlinux If the runtime results will favor sparsmem, it might be still worthwhile using it instead of discontigmem. Otherwise ARC is doomed to keep DISCONTIGMEM forever ;-) I've defined the constants required for the SPARSEMEM based on the comments inside the code, if the actual parameters might be different, please let me know, I'll update the arch/arc/include/asm/sparsemem.h. Currently, I presumed that for non-PAE the physical address size is 32 bits and there maybe up to two memory banks: at 0x8zz and at 0x0zz. For the PAE case, the maximal physical address is 40 bits and the memory can be populated at 0x8zz or 0x1zzz. -- Sincerely yours, Mike. Mike Rapoport (1): arc: add sparsemem support arch/arc/Kconfig | 9 +++++ arch/arc/include/asm/sparsemem.h | 13 +++++++ arch/arc/mm/init.c | 84 ++++++++++++++++++++++++++++------------ include/linux/mm.h | 3 ++ mm/page_alloc.c | 37 ++++++++++++++++++ 5 files changed, 121 insertions(+), 25 deletions(-) create mode 100644 arch/arc/include/asm/sparsemem.h -- 2.7.4 _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
