From: Cliff Wickman Date: Wed, 8 Sep 2010 15:14:27 +0000 (-0500) Subject: x86, kdump: Change copy_oldmem_page() to use cached addressing X-Git-Tag: firefly_0821_release~9833^2~79^2^2~332 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b6af39cd87b99525e0e6838bdee5819104cc1182;p=firefly-linux-kernel-4.4.55.git 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 Acked-by: "Eric W. Biederman" Cc: kexec@lists.infradead.org LKML-Reference: Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c index ce96a6b575b7..994828899e09 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;