On Wed, 2009-09-02 at 16:27 -0700, Luck, Tony wrote: > >> diff -BruN linux-2.6.31-rc6/arch/ia64/include/asm/page.h > >> linux-2.6.31-rc6-lockdep/arch/ia64/include/asm/page.h > >> --- linux-2.6.31-rc6/arch/ia64/include/asm/page.h 2009-08-13 > >> 15:43:34.000000000 -0700 > >> +++ linux-2.6.31-rc6-lockdep/arch/ia64/include/asm/page.h 2009-08-23 > >> 18:59:00.000000000 -0700 > >> @@ -41,7 +41,7 @@ > >> #define PAGE_SIZE (__IA64_UL_CONST(1) << PAGE_SHIFT) > >> #define PAGE_MASK (~(PAGE_SIZE - 1)) > >> > >> -#define PERCPU_PAGE_SHIFT 16 /* log2() of max. size of per-CPU area */ > >> +#define PERCPU_PAGE_SHIFT 20 /*16 log2() of max. size of per-CPU area */ > >> #define PERCPU_PAGE_SIZE (__IA64_UL_CONST(1) << PERCPU_PAGE_SHIFT) > > > > Why was this seemingly unrelated change done in a lockdep patch? > > IIRC it is because the lockdep code needs a lot more percpu memory than the > 64K that ia64 allocates. > > But I think that I'd prefer to only allocate the extra space when it > is needed: > > #ifdef CONFIG_LOCKDEP > #define PERCPU_PAGE_SHIFT 20 /* Need a Megabyte for lockdep */ > #else > #define PERCPU_PAGE_SHIFT 16 /* 64K should be enough for normal use */ > #endif Hmm, isn't all that percpu stuff in a special section, who's size you can query at boot time and set-up accordingly? -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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