Messages in this thread Patch in this message | | | Date | Fri, 19 Nov 2010 14:00:54 -0800 | From | Greg KH <> | Subject | [23/66] x86, kdump: Change copy_oldmem_page() to use cached addressing |
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2.6.36-stable review patch. If anyone has any objections, please let us know.
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From: Cliff Wickman <cpw@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 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>
--- arch/x86/kernel/crash_dump_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 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 p if (!csize) return 0; - vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE); + vaddr = ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE); if (!vaddr) return -ENOMEM;
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