On Tue, Jun 03, 2014 at 04:47:52PM -0700, David Daney wrote: > On 06/03/2014 03:47 PM, Ralf Baechle wrote: > [...] > >>--- a/arch/mips/include/asm/addrspace.h > >>+++ b/arch/mips/include/asm/addrspace.h > >>@@ -51,8 +51,14 @@ > >> * Returns the physical address of a CKSEGx / XKPHYS address > >> */ > >> #define CPHYSADDR(a) ((_ACAST32_(a)) & 0x1fffffff) > >>+ > >>+#ifndef CONFIG_NUMA > >> #define XPHYSADDR(a) ((_ACAST64_(a)) & \ > >> _CONST64_(0x000000ffffffffff)) > >>+#else > >>+#define XPHYSADDR(a) ((_ACAST64_(a)) & \ > >>+ _CONST64_(0x0000ffffffffffff)) > >>+#endif > > > >The mask in XPHYSADDR is a function of the processor architecture, not > >imlementation, not NUMA. The latest version of the MIPS architecture > >permits PABITS to be as large as 49 bits, so the mask should be > >0x0001ffffffffffff. Always. > > > >>diff --git a/arch/mips/include/asm/sparsemem.h b/arch/mips/include/asm/sparsemem.h > >>index d2da53c..c001a90 100644 > >>--- a/arch/mips/include/asm/sparsemem.h > >>+++ b/arch/mips/include/asm/sparsemem.h > >>@@ -11,7 +11,12 @@ > >> #else > >> # define SECTION_SIZE_BITS 28 > >> #endif > >>+ > >>+#ifdef CONFIG_NUMA > >>+#define MAX_PHYSMEM_BITS 48 > >>+#else > >> #define MAX_PHYSMEM_BITS 35 > >>+#endif > > > >Essentially the same comment as for XPHYSADDR above. > > Are you saying to change it to 49 unconditionally for all configurations? > > That would work for OCTEON too, where we have had to increase it to 42. > > What are the implications for kernel data structures if this is set > many orders of magnitude greater than the actual number of bits used > on a system? Shouldn't make a significant difference; the value is used to compute certain limits in sparse.c and a bitmap in zsmalloc.c which is used only when CONFIG_ZSMALLOC is enabled. A more important value which I haven't noticed the Looongson patches to modify is SECTION_SIZE_BITS in <asm/sparsemem.h>: #if defined(CONFIG_MIPS_HUGE_TLB_SUPPORT) && defined(CONFIG_PAGE_SIZE_64KB) # define SECTION_SIZE_BITS 29 #else # define SECTION_SIZE_BITS 28 #endif Don't ask me why its definition depends on MIPS_HUGE_TLB_SUPPORT and PAGE_SIZE_64KB - the value describes the larges chunk of contiguous memory (that is for example memory per node) and that doesn't depend on these CONFIG_* symbols. Ralf
