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From: Toshi Kani <toshi.kani@hp.com>
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 <toshi.kani@hp.com>
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	[thread overview]
Message-ID: <1422314009-31667-8-git-send-email-toshi.kani@hp.com> (raw)
In-Reply-To: <1422314009-31667-1-git-send-email-toshi.kani@hp.com>

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 <toshi.kani@hp.com>
---
 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
 #

      parent reply	other threads:[~2015-01-26 23:30 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-26 23:13 [RFC PATCH 0/7] Kernel huge I/O mapping support Toshi Kani
2015-01-26 23:13 ` [RFC PATCH 1/7] mm: Change __get_vm_area_node() to use fls_long() Toshi Kani
2015-01-26 23:13 ` [RFC PATCH 2/7] lib: Add huge I/O map capability interfaces Toshi Kani
2015-01-26 23:54   ` Andrew Morton
2015-01-27  1:01     ` Toshi Kani
2015-01-27 21:37       ` Andrew Morton
2015-01-27 22:01         ` Toshi Kani
2015-02-05 20:56       ` Toshi Kani
2015-01-26 23:13 ` [RFC PATCH 3/7] mm: Change ioremap to set up huge I/O mappings Toshi Kani
2015-01-26 23:58   ` Andrew Morton
2015-01-27  0:01     ` Toshi Kani
2015-01-26 23:13 ` [RFC PATCH 4/7] mm: Change vunmap to tear down huge KVA mappings Toshi Kani
2015-01-26 23:13 ` [RFC PATCH 5/7] x86, mm: Support huge KVA mappings on x86 Toshi Kani
2015-01-26 23:13 ` [RFC PATCH 6/7] x86, mm: Support huge I/O " Toshi Kani
2015-01-26 23:13 ` Toshi Kani [this message]

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