Messages in this thread | | | Date | Mon, 1 Oct 2012 12:00:26 +0100 | From | Stefano Stabellini <> | Subject | Re: [PATCH 04/13] x86, mm: Revert back good_end setting for 64bit |
| |
On Sun, 30 Sep 2012, Yinghai Lu wrote: > After > > | commit 8548c84da2f47e71bbbe300f55edb768492575f7 > | Author: Takashi Iwai <tiwai@suse.de> > | Date: Sun Oct 23 23:19:12 2011 +0200 > | > | x86: Fix S4 regression > | > | Commit 4b239f458 ("x86-64, mm: Put early page table high") causes a S4 > | regression since 2.6.39, namely the machine reboots occasionally at S4 > | resume. It doesn't happen always, overall rate is about 1/20. But, > | like other bugs, once when this happens, it continues to happen. > | > | This patch fixes the problem by essentially reverting the memory > | assignment in the older way. > > Have some page table around 512M again, that will prevent kdump to find 512M > under 768M. > > We need revert that reverting, so we could put page table high again for 64bit. > > Takashi agreed that S4 regression could be something else. > > https://lkml.org/lkml/2012/6/15/182 > > Signed-off-by: Yinghai Lu <yinghai@kernel.org> > --- > arch/x86/mm/init.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c > index 9f69180..aadb154 100644 > --- a/arch/x86/mm/init.c > +++ b/arch/x86/mm/init.c > @@ -76,8 +76,8 @@ static void __init find_early_table_space(struct map_range *mr, > #ifdef CONFIG_X86_32 > /* for fixmap */ > tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE); > -#endif > good_end = max_pfn_mapped << PAGE_SHIFT; > +#endif > > base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE); > if (!base)
Isn't this going to cause init_memory_mapping to allocate pagetable pages from memory not yet mapped? Last time I spoke with HPA and Thomas about this, they seem to agree that it isn't a very good idea. Also, it is proven to cause a certain amount of headaches on Xen, see commit d8aa5ec3382e6a545b8f25178d1e0992d4927f19.
| |