From: Cliff Wickman <cpw@xxxxxxx> 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. (Does anyone know of a reason why copy_oldmem_page() would need to use uncached addresses?) Diffed against 2.6.36-rc3 Signed-off-by: Cliff Wickman <cpw at sgi.com> --- arch/x86/kernel/crash_dump_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linus.current/arch/x86/kernel/crash_dump_64.c =================================================================== --- linus.current.orig/arch/x86/kernel/crash_dump_64.c +++ linus.current/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;
