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Message-ID: <20091002033508.GA8436@basil.fritz.box> Date: Fri, 2 Oct 2009 05:35:08 +0200 From: Andi Kleen <andi@...stfloor.org> To: x86@...nel.org, linux-kernel@...r.kernel.org Cc: venkatesh.pallipadi@...el.com, stable@...nel.org Subject: [PATCH] x86: Use ioremap_cache() for crash dump copies During code review I noticed that when reading the previous kernel memory from a kdump kernel ioremap() is used. This was ok before the PAT changes, but with PAT ioremap() this results in an uncached mapping, which is very slow. Change it to ioremap_cache(). This is fine because this code only reads real memory, no IO mappings. I haven't run numbers, but I suspect this will speed up crash dumping somewhat. Only affects 64bit, 32bit uses a different method. Might be a stable candidate. Signed-off-by: Andi Kleen <ak@...ux.intel.com> --- arch/x86/kernel/crash_dump_64.c | 2 +- 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 045b36c..bf43188 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; -- 1.6.0.2 -- ak@...ux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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