linux-kernel - [PATCH 2/5] staging: zsmalloc: add ZS_MAX_PAGES_PER

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Message-Id: <1330968804-8098-3-git-send-email-sjenning@linux.vnet.ibm.com>
Date:	Mon,  5 Mar 2012 11:33:21 -0600
From:	Seth Jennings <sjenning@...ux.vnet.ibm.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Seth Jennings <sjenning@...ux.vnet.ibm.com>,
	Dan Magenheimer <dan.magenheimer@...cle.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Nitin Gupta <ngupta@...are.org>,
	Robert Jennings <rcj@...ux.vnet.ibm.com>,
	devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [PATCH 2/5] staging: zsmalloc: add ZS_MAX_PAGES_PER_ZSPAGE

This patch moves where max_zspage_order is declared and
changes its meaning.  "Order" typically implies 2^order
of something; however, it is currently being used as the
"maximum number of single pages in a zspage".  To add clarity,
ZS_MAX_ZSPAGE_ORDER is now used to calculate ZS_MAX_PAGES_PER_ZSPAGE,
which is 2^ZS_MAX_ZSPAGE_ORDER and is the upper bound on the number
of pages in a zspage.

Signed-off-by: Seth Jennings <sjenning@...ux.vnet.ibm.com>
---
 drivers/staging/zsmalloc/zsmalloc-main.c |    2 +-
 drivers/staging/zsmalloc/zsmalloc_int.h  |   13 +++++++------
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/staging/zsmalloc/zsmalloc-main.c b/drivers/staging/zsmalloc/zsmalloc-main.c
index 240bcbf..09caa4f 100644
--- a/drivers/staging/zsmalloc/zsmalloc-main.c
+++ b/drivers/staging/zsmalloc/zsmalloc-main.c
@@ -186,7 +186,7 @@ static int get_zspage_order(int class_size)
 	/* zspage order which gives maximum used size per KB */
 	int max_usedpc_order = 1;
 
-	for (i = 1; i <= max_zspage_order; i++) {
+	for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) {
 		int zspage_size;
 		int waste, usedpc;
 
diff --git a/drivers/staging/zsmalloc/zsmalloc_int.h b/drivers/staging/zsmalloc/zsmalloc_int.h
index e06e142..4d66d2d 100644
--- a/drivers/staging/zsmalloc/zsmalloc_int.h
+++ b/drivers/staging/zsmalloc/zsmalloc_int.h
@@ -26,6 +26,13 @@
 #define ZS_ALIGN		8
 
 /*
+ * A single 'zspage' is composed of up to 2^N discontiguous 0-order (single)
+ * pages. ZS_MAX_ZSPAGE_ORDER defines upper limit on N.
+ */
+#define ZS_MAX_ZSPAGE_ORDER 2
+#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER)
+
+/*
  * Object location (<PFN>, <obj_idx>) is encoded as
  * as single (void *) handle value.
  *
@@ -59,12 +66,6 @@
 					ZS_SIZE_CLASS_DELTA + 1)
 
 /*
- * A single 'zspage' is composed of N discontiguous 0-order (single) pages.
- * This defines upper limit on N.
- */
-static const int max_zspage_order = 4;
-
-/*
  * We do not maintain any list for completely empty or full pages
  */
 enum fullness_group {
-- 
1.7.5.4

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