On Mon, Sep 15, 2008 at 10:08:48AM -0700, Jay Lan wrote: > Simon Horman wrote: > > On Thu, Sep 11, 2008 at 04:00:08PM -0700, Jay Lan wrote: > >> Currently a memory segment in memory map with attribute of EFI_MEMORY_UC > >> is denoted as "System RAM" in /proc/iomem, while memory of attribute > >> (EFI_MEMORY_WB|EFI_MEMORY_UC) is also labeled the same. > >> > >> The kexec utility then includes uncached memory as part of vmcore. The > >> kdump kernel MCA'ed when it tries to save the vmcore to a disk. A normal > >> "cached" access may cause MCAs. > >> > >> This patch would label memory with attribute of EFI_MEMORY_UC only as > >> "Uncached RAM" so that kexec would know not to include it in the vmcore. > >> I will submit a separate kexec-tools patch to the kexec list. > >> > >> Signed-off-by: Jay Lan <jlan at sgi.com> > > > > Hi Jay, > > > > I've taken a look on an RX2620, Tiger2 and Tiger4 and none of these > > machines have EFI memory regions that are covered by this new check. That > > is, any regions with the EFI_MEMORY_UC bit set in the attribute either also > > have other attibute bits set, or are of a type not covered by this. > > Great! So the change affects most likely only SGI Altix machines. > Below is the EFI memory regions of one node of an Altix machine: > > PAL_code 0000000001000000-0000000001FFFFFF 0000000000001000 > 8000000000000009 > MemMapIO 00000000FF000000-00000000FFFFFFFF 0000000000001000 > 8000000000000001 > Unusable 0000006000000000-000000600000FFFF 0000000000000010 > 0000000000000009 > RT_data 0000006000010000-00000060000FFFFF 00000000000000F0 > 8000000000001001 > BS_data 0000006000100000-00000060003FFFFF 0000000000000300 > 0000000000000001 > RT_data 0000006000400000-0000006001FFFFFF 0000000000001C00 > 8000000000001009 > RT_data 0000006002000000-0000006002FFFFFF 0000000000001000 > 8000000000000009 > BS_data 0000006003000000-0000006033DFFFFF 0000000000030E00 > 0000000000000009 > available 0000006033E00000-00000060F7FFFFFF 00000000000C4200 > 0000000000000009 > MemMapIO 0000008000000000-0000009FFFFFFFFF 0000000002000000 > 8000000000000003 > > The first BS_data region starting at 0x0000006000100000 is the > case. That memory is part of Altix "fetchop" space (AKA mspec). > > Since it does not affect IA64 machines you have, this patch should > be very safe, yet needed for Altix. Thats what I was hoping your reaction would be. Acked-by: Simon Horman <horms at verge.net.au> -- Simon Horman VA Linux Systems Japan K.K., Sydney, Australia Satellite Office H: www.vergenet.net/~horms/ W: www.valinux.co.jp/en
