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Subject[PATCH 2/5] staging: zsmalloc: add ZS_MAX_PAGES_PER_ZSPAGE
Date
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@linux.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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