From: "K. Y. Srinivasan" <kys@microsoft.com>
To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
        devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com,
        andi@firstfloor.org, akpm@linux-foundation.org, linux-mm@kvack.org
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Subject: [PATCH 1/1] mm: Export split_page().
Date: Sun,  3 Mar 2013 18:27:55 -0800
Message-Id: <1362364075-14564-1-git-send-email-kys@microsoft.com>
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1215
Lines: 33

The split_page() function will be very useful for balloon drivers. On Hyper-V,
it will be very efficient to use 2M allocations in the guest as this (a) makes
the ballooning protocol with the host that much more efficient and (b) moving
memory in 2M chunks minimizes fragmentation in the host. Export the split_page()
function to let the guest allocations be in 2M chunks while the host is free to
return this memory at arbitrary granularity.


Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
---
 mm/page_alloc.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6cacfee..7e0ead6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1404,6 +1404,7 @@ void split_page(struct page *page, unsigned int order)
 	for (i = 1; i < (1 << order); i++)
 		set_page_refcounted(page + i);
 }
+EXPORT_SYMBOL_GPL(split_page);
 
 static int __isolate_free_page(struct page *page, unsigned int order)
 {
-- 
1.7.4.1

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