Messages in this thread | | | Date | Wed, 18 Jun 2008 15:41:52 +0200 | From | Jiri Slaby <> | Subject | Re: [PATCH 1/1] MM: virtual address debug |
| |
Nick Piggin napsal(a): > On Thursday 12 June 2008 21:56, Jiri Slaby wrote: >> Add some (configurable) expensive sanity checking to catch wrong address >> translations on x86. >> >> - create linux/mmdebug.h file to be able include this file in >> asm headers to not get unsolvable loops in header files >> - __phys_addr on x86_32 became a function in ioremap.c since >> PAGE_OFFSET, is_vmalloc_addr and VMALLOC_* non-constasts are undefined >> if declared in page_32.h > > Uh, I have to disagree with this. __phys_addr is used in some really > performance critical parts of the kernel, and the function calls are > free mindset is just wrong. Even for modern x86 CPUs, the function > call return might take 10 cycles or more when you include all costs. > > And for something like this > > #define __phys_addr(x) ((x) - PAGE_OFFSET) > > the code to call the function is probably bigger than inline generated > code anyway.
Thanks for comments, well, are you OK with __phys_addr being a function only on CONFIG_VIRTUAL_DEBUG?
| |