From 37a2f9f30a360fb03522d15c85c78265ccd80287 Mon Sep 17 00:00:00 2001 From: Cliff Wickman Date: Wed, 8 Sep 2010 10:14:27 -0500 Subject: [PATCH] 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 Acked-by: "Eric W. Biederman" Cc: kexec@lists.infradead.org Cc: # as far back as it would apply LKML-Reference: Signed-off-by: Ingo Molnar --- arch/x86/kernel/crash_dump_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c index 045b36cada65..bf43188ca654 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;