Matt Mackall a écrit :
On Thu, Dec 13, 2007 at 11:20:44PM +0100, Adrian Bunk wrote:
I tried the following patch with a full x86 .config [1]:
--- a/include/asm-x86/cache.h
+++ b/include/asm-x86/cache.h
-#define __read_mostly __attribute__((__section__(".data.read_mostly")))
+/* #define __read_mostly __attribute__((__section__(".data.read_mostly"))) */
The result [2,3] was:
-rwxrwxr-x 1 bunk bunk 46607243 2007-12-13 19:50 vmlinux.old
-rwxrwxr-x 1 bunk bunk 46598691 2007-12-13 21:55 vmlinux
It's not a surprise that the kernel can become bigger when __read_mostly
gets used, especially in cases where __read_mostly prevents gcc
optimizations.
My question is:
Is there anywhere in the kernel a case where __read_mostly brings a
measurable improvement or can it be removed?
Yes, but perhaps we can put it under CONFIG_BASE_FULL?
Yes, we probably can do something like that (in addition to !CONFIG_SMP)
-
To unsubscribe from this list: send the line "unsubscribe linux-arch" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
