From: David S. Miller <davem@davemloft.net>
Date: Fri, 12 Sep 2008 06:36:32 +0000 (-0700)
Subject: sparc64: Define WANT_PAGE_VIRTUAL
X-Git-Tag: firefly_0821_release~17814^2~33
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b0f1e7962f93a78630161c7c9fc263de43c101ac;p=firefly-linux-kernel-4.4.55.git

sparc64: Define WANT_PAGE_VIRTUAL

As sparse warns, without this struct page pointer subtraction is
extremely expensive, and this is a pretty common operation in
fast paths.

With this define struct page becomes 64 bytes which makes for a
simple subtract and shift, instead of a costly divide or reciprocol
multiply.

Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/arch/sparc/include/asm/page_64.h b/arch/sparc/include/asm/page_64.h
index b579b910ef51..4274ed13ddb2 100644
--- a/arch/sparc/include/asm/page_64.h
+++ b/arch/sparc/include/asm/page_64.h
@@ -38,6 +38,8 @@
 
 #ifndef __ASSEMBLY__
 
+#define WANT_PAGE_VIRTUAL
+
 extern void _clear_page(void *page);
 #define clear_page(X)	_clear_page((void *)(X))
 struct page;