From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757459AbbAZXaS (ORCPT ); Mon, 26 Jan 2015 18:30:18 -0500 Received: from g9t1613g.houston.hp.com ([15.240.0.71]:54950 "EHLO g9t1613g.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757384AbbAZXaI (ORCPT ); Mon, 26 Jan 2015 18:30:08 -0500 From: Toshi Kani To: akpm@linux-foundation.org, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, arnd@arndb.de, linux-mm@kvack.org Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Toshi Kani Subject: [RFC PATCH 7/7] mm: Add config HUGE_IOMAP to enable huge I/O mappings Date: Mon, 26 Jan 2015 16:13:29 -0700 Message-Id: <1422314009-31667-8-git-send-email-toshi.kani@hp.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1422314009-31667-1-git-send-email-toshi.kani@hp.com> References: <1422314009-31667-1-git-send-email-toshi.kani@hp.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add config HUGE_IOMAP to enable huge I/O mappings. This feature is set to Y by default when HAVE_ARCH_HUGE_VMAP is defined on the architecture. Note, user can also disable this feature at boot-time by the kernel option "nohgiomap" if necessary. Signed-off-by: Toshi Kani --- mm/Kconfig | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/mm/Kconfig b/mm/Kconfig index 1d1ae6b..eb738ae 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -444,6 +444,17 @@ choice benefit. endchoice +config HUGE_IOMAP + bool "Kernel huge I/O mapping support" + depends on HAVE_ARCH_HUGE_VMAP + default y + help + Kernel huge I/O mapping allows the kernel to transparently + create I/O mappings with huge pages for memory-mapped I/O + devices whenever possible. This feature can improve + performance of certain devices with large memory size, such + as NVM, and reduce the time to create their mappings. + # # UP and nommu archs use km based percpu allocator #