From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f46.google.com (mail-qg0-f46.google.com [209.85.192.46]) by kanga.kvack.org (Postfix) with ESMTP id 482DF6B0075 for ; Mon, 26 Jan 2015 18:30:08 -0500 (EST) Received: by mail-qg0-f46.google.com with SMTP id i50so9409376qgf.5 for ; Mon, 26 Jan 2015 15:30:08 -0800 (PST) Received: from g5t1625.atlanta.hp.com (g5t1625.atlanta.hp.com. [15.192.137.8]) by mx.google.com with ESMTPS id a7si15394555qam.2.2015.01.26.15.30.07 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 26 Jan 2015 15:30:07 -0800 (PST) From: 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> 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: owner-linux-mm@kvack.org List-ID: 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 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 # -- 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