On Fri, Jul 13, 2012 at 9:41 PM, Stefan Bader <[email protected]> wrote: > I was bisecting a problem on 64bit where any attempt to cause a crash kernel > to > boot would hang. The bisect ended up on commit 722bc6b (x86/mm: Fix the size > calculation of mapping tables) and somehow, looking at the calling function > and > the ranges printed on boot, I think the calculations should only be done in > the > 32bit case. > > On 64bit: > [ 0.000000] init_memory_mapping: [mem 0x00000000-0x77e87fff] > [ 0.000000] [mem 0x00000000-0x77dfffff] page 2M > [ 0.000000] [mem 0x77e00000-0x77e87fff] page 4k > > Attached patch would fix this if you agree with it. Thanks. > > -Stefan > > > From 6b679d1af20656929c0e829f29eed60b0a86a74f Mon Sep 17 00:00:00 2001 > From: Stefan Bader <[email protected]> > Date: Fri, 13 Jul 2012 15:16:33 +0200 > Subject: [PATCH] x86/mm: Limit 2/4M size calculation to x86_32 > > commit 722bc6b (x86/mm: Fix the size calculation of mapping tables) > did modify the extra space calculation for mapping tables in order > to make up for the first 2/4M memory range using 4K pages. > However this setup is only used when compiling for 32bit. On 64bit > there is only the trailing area of 4K pages (which is already added). > > The code was already adapted once for things went wrong on a 8TB > machine (bd2753b x86/mm: Only add extra pages count for the first memory > range during pre-allocation early page table space), but it looks a bit > like it currently would overdo things for 64bit. > I only noticed while bisecting for the reason I could not make a crash > kernel boot (which ended up on this patch). > > Signed-off-by: Stefan Bader <[email protected]> > Cc: WANG Cong <[email protected]> > Cc: Yinghai Lu <[email protected]> > Cc: Tejun Heo <[email protected]>
Acked-by: Cong Wang <[email protected]> Sorry for that I was not aware of x86_64 is different with x86 in the first 2/4M. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
