x86, kdump: Change copy_oldmem_page() to use cached addressing
authorCliff Wickman <cpw@sgi.com>
Wed, 8 Sep 2010 15:14:27 +0000 (10:14 -0500)
committerIngo Molnar <mingo@elte.hu>
Thu, 9 Sep 2010 07:46:23 +0000 (09:46 +0200)
commit37a2f9f30a360fb03522d15c85c78265ccd80287
treebcc77b64a38aff205daacea238cf0586e8301c68
parent1c5f50ee347daea013671f718b70cd6bf497bef9
x86, kdump: Change copy_oldmem_page() to use cached addressing

The copy of /proc/vmcore to a user buffer proceeds much faster
if the kernel addresses memory as cached.

With this patch we have seen an increase in transfer rate from
less than 15MB/s to 80-460MB/s, depending on size of the
transfer. This makes a big difference in time needed to save a
system dump.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: kexec@lists.infradead.org
Cc: <stable@kernel.org> # as far back as it would apply
LKML-Reference: <E1OtMLz-0001yp-Ia@eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
arch/x86/kernel/crash_dump_64.c