From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f173.google.com (mail-ob0-f173.google.com [209.85.214.173]) by kanga.kvack.org (Postfix) with ESMTP id 5BD08828EE for ; Sat, 9 Jan 2016 17:33:36 -0500 (EST) Received: by mail-ob0-f173.google.com with SMTP id bx1so353804270obb.0 for ; Sat, 09 Jan 2016 14:33:36 -0800 (PST) Received: from mail-ob0-x229.google.com (mail-ob0-x229.google.com. [2607:f8b0:4003:c01::229]) by mx.google.com with ESMTPS id k82si13637933oia.120.2016.01.09.14.33.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 09 Jan 2016 14:33:35 -0800 (PST) Received: by mail-ob0-x229.google.com with SMTP id wp13so245591654obc.1 for ; Sat, 09 Jan 2016 14:33:35 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <19f6403f2b04d3448ed2ac958e656645d8b6e70c.1452297867.git.tony.luck@intel.com> From: Andy Lutomirski Date: Sat, 9 Jan 2016 14:33:16 -0800 Message-ID: Subject: Re: [PATCH v8 3/3] x86, mce: Add __mcsafe_copy() Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Dan Williams Cc: Tony Luck , linux-nvdimm , Borislav Petkov , "linux-kernel@vger.kernel.org" , Andrew Morton , Robert , Ingo Molnar , "linux-mm@kvack.org" , X86 ML On Sat, Jan 9, 2016 at 2:15 PM, Dan Williams wrote: > On Sat, Jan 9, 2016 at 11:39 AM, Tony Luck wrote: >> On Sat, Jan 9, 2016 at 9:57 AM, Andy Lutomirski wrote: >>> On Sat, Jan 9, 2016 at 9:48 AM, Tony Luck wrote: >>>> ERMS? >>> >>> It's the fast string extension, aka Enhanced REP MOV STOS. On CPUs >>> with that feature (and not disabled via MSR), plain ol' rep movs is >>> the fastest way to copy bytes. I think this includes all Intel CPUs >>> from SNB onwards. >> >> Ah ... very fast at copying .. but currently not machine check recoverable. > > Hmm, I assume for the pmem driver I'll want to check at runtime if the > cpu has machine check recovery and fall back to the faster copy if > it's not available? Shouldn't that logic live in the mcsafe_copy routine itself rather than being delegated to callers? --Andy -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org