[078/474] x86, kdump: Change copy_oldmem_page() to use cached addressing
gregkh at suse.de
Thu Mar 17 17:22:08 EDT 2011
2.6.33-longterm review patch. If anyone has any objections, please let us know.
From: Cliff Wickman <cpw at sgi.com>
commit 37a2f9f30a360fb03522d15c85c78265ccd80287 upstream.
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
Signed-off-by: Cliff Wickman <cpw at sgi.com>
Acked-by: "Eric W. Biederman" <ebiederm at xmission.com>
Cc: kexec at lists.infradead.org
LKML-Reference: <E1OtMLz-0001yp-Ia at eag09.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo at elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>
arch/x86/kernel/crash_dump_64.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
@@ -34,7 +34,7 @@ ssize_t copy_oldmem_page(unsigned long p
- vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
+ vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
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