On Wed, Jul 4, 2012 at 2:20 AM, Mel Gorman <mgorman@xxxxxxx> wrote: > On Wed, Jul 04, 2012 at 09:40:30AM +0800, Jiang Liu wrote: >> > It's a bit ugly calling set_pageblock_order() from both sparse_init() >> > and from free_area_init_core(). Can we find a single place from which >> > to call it? It looks like here: >> > >> > --- a/init/main.c~a >> > +++ a/init/main.c >> > @@ -514,6 +514,7 @@ asmlinkage void __init start_kernel(void >> > __stop___param - __start___param, >> > -1, -1, &unknown_bootoption); >> > >> > + set_pageblock_order(); >> > jump_label_init(); >> > >> > /* >> > >> > would do the trick? >> > >> > (free_area_init_core is __paging_init and set_pageblock_order() is >> > __init. I'm too lazy to work out if that's wrong) >> >> Hi Andrew, >> Thanks for you comments. Yes, this's an issue. >> And we are trying to find a way to setup pageorder_block as >> early as possible. Yinghai has suggested a good way for IA64, >> but we still need help from PPC experts because PPC has the >> same issue and I'm not familiar with PPC architecture. >> We will submit another patch once we find an acceptable >> solution here. > > I think it's overkill to try and do this on a per-architecture basis unless > you are aware of a case where the per-architecture code cares about the > value of pageblock_order. I find it implausible that the architecture > needs to know the value very early in boot as pageblock_order is part of > the arch-independent memory model. Andrew's suggestion seems reasonable > to me once the section mess is figured out. cma, dma_continugous_reserve is referring pageblock_order very early too. just after init_memory_mapping() for x86's setup_arch. so set pageblock_order early looks like my -v2 patch is right way. current question: need to powerpc guys to check who to set that early. Thanks Yinghai -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>