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authorCliff Wickman <cpw@sgi.com>2010-09-08 10:14:27 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2010-11-22 11:03:05 -0800
commitb6af39cd87b99525e0e6838bdee5819104cc1182 (patch)
treef585b89c50b1f8f15dceafe2a454a10de84c53ca
parentbbfc3a3c96fca7386244f1c0ddf88c8a958f044d (diff)
x86, kdump: Change copy_oldmem_page() to use cached addressing
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 system dump. Signed-off-by: Cliff Wickman <cpw@sgi.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Cc: kexec@lists.infradead.org LKML-Reference: <E1OtMLz-0001yp-Ia@eag09.americas.sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--arch/x86/kernel/crash_dump_64.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index ce96a6b575b..994828899e0 100644
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -34,7 +34,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
if (!csize)
return 0;
- vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
+ vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
if (!vaddr)
return -ENOMEM;