From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f169.google.com (mail-wi0-f169.google.com [209.85.212.169]) by kanga.kvack.org (Postfix) with ESMTP id 09BD382997 for ; Fri, 22 May 2015 03:02:38 -0400 (EDT) Received: by wibt6 with SMTP id t6so37141582wib.0 for ; Fri, 22 May 2015 00:02:37 -0700 (PDT) Received: from Galois.linutronix.de (Galois.linutronix.de. [2001:470:1f0b:db:abcd:42:0:1]) by mx.google.com with ESMTPS id bo1si2205548wjb.27.2015.05.22.00.02.36 for (version=TLSv1.2 cipher=RC4-SHA bits=128/128); Fri, 22 May 2015 00:02:36 -0700 (PDT) Date: Fri, 22 May 2015 09:02:39 +0200 (CEST) From: Thomas Gleixner Subject: Re: [PATCH v9 3/10] x86, asm: Change is_new_memtype_allowed() for WT In-Reply-To: <1431551151-19124-4-git-send-email-toshi.kani@hp.com> Message-ID: References: <1431551151-19124-1-git-send-email-toshi.kani@hp.com> <1431551151-19124-4-git-send-email-toshi.kani@hp.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Toshi Kani Cc: hpa@zytor.com, mingo@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-nvdimm@ml01.01.org, jgross@suse.com, stefan.bader@canonical.com, luto@amacapital.net, hmh@hmh.eng.br, yigal@plexistor.com, konrad.wilk@oracle.com, Elliott@hp.com, mcgrof@suse.com, hch@lst.de On Wed, 13 May 2015, Toshi Kani wrote: > __ioremap_caller() calls reserve_memtype() to set new_pcm > (existing map type if any), and then calls > is_new_memtype_allowed() to verify if converting to new_pcm > is allowed when pcm (request type) is different from new_pcm. > > When WT is requested, the caller expects that writes are > ordered and uncached. Therefore, this patch changes > is_new_memtype_allowed() to disallow the following cases. > > - If the request is WT, mapping type cannot be WB > - If the request is WT, mapping type cannot be WC > > Signed-off-by: Toshi Kani Reviewed-by: Thomas Gleixner -- 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