On Mon, 2008-11-24 at 14:07 -0600, Hollis Blanchard wrote: > On Fri, 2008-11-14 at 16:09 -0600, Hollis Blanchard wrote: > > > > If this is all too much, then I'm close to giving up and burning a > > 64KB page, which requires only ALIGN_DOWN() in the kernel. > > ppc: force memory size to be a multiple of PAGE_SIZE > > Ensure that total memory size is page-aligned, because otherwise > bootmem.c gets upset. > > This error case was triggered by using 64 KiB pages in the kernel while > arch/powerpc/boot/4xx.c arbitrarily reduced the amount of memory by 4096 (to > work around the "CHIP11" errata which affects the last 256 bytes of physical > memory). > > Signed-off-by: Hollis Blanchard <[EMAIL PROTECTED]> > --- > This is on a common code path, and lmb_enforce_memory_limit() will now > always take action, so wider testing would be good. > > This patch supercedes http://patchwork.ozlabs.org/patch/8211/ . > > diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c > --- a/arch/powerpc/kernel/prom.c > +++ b/arch/powerpc/kernel/prom.c > @@ -1200,6 +1200,11 @@ void __init early_init_devtree(void *par > early_reserve_mem(); > phyp_dump_reserve_mem(); > > + /* Ensure that total memory size is page-aligned, because otherwise > + * bootmem.c gets upset. */ > + lmb_analyze(); > + memory_limit = lmb_phys_mem_size() & PAGE_MASK;
All of the current code using memory_limit looks like it'll be safe with this change, although there are several cases of this we could remove: if (memory_limit && <some other condition>) Because memory_limit will now always be true. Still, I think it would be better to only set memory_limit when the mem size is not a multiple of the PAGE_SIZE - so that memory_limit retains it's function as both the value of the limit and a boolean. cheers -- Michael Ellerman OzLabs, IBM Australia Development Lab wwweb: http://michael.ellerman.id.au phone: +61 2 6212 1183 (tie line 70 21183) We do not inherit the earth from our ancestors, we borrow it from our children. - S.M.A.R.T Person
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