Ralf Baechle wrote: > On Thu, Jul 04, 2002 at 08:18:41PM +0200, Carsten Langgaard wrote: > > > > any power of 2 > PAGE_SIZE. > > > > Ok, I see, but is there any reason for us to be different than the > > rest of the world ? > > Imho the your question already wrong :-) Any assumption about the > constant's value in a piece of code is wrong. > > The reason why the constant's value was choosen are virtually indexed > caches. The value allows attaching of shared memory segment without > any cache flushes. > > Other architectures also use different values from PAGE_SIZE like IA64 1MB, > SH 16kB and Sparc not even a constant value accross all architectures > variants, so unlike what your posting implicates we're not that unusual. Using PAGE_SIZE is ok, even though it may differ from different architecture, because SHMLBA is defined as the following in /usr/include/sys/shm.h: #define SHMLBA (__getpagesize ()) So I would expect the user application and the kernel should have the same idea of what the size is. > Ralf -- _ _ ____ ___ Carsten Langgaard Mailto:carstenl@mips.com |\ /|||___)(___ MIPS Denmark Direct: +45 4486 5527 | \/ ||| ____) Lautrupvang 4B Switch: +45 4486 5555 TECHNOLOGIES 2750 Ballerup Fax...: +45 4486 5556 Denmark http://www.mips.com
