From: Yogesh Lal <y...@codeaurora.org>
Add a kernel parameter stack_hash_order to configure STACK_HASH_SIZE.
Aim is to have configurable value for STACK_HASH_SIZE, so that one
can configure it depending on usecase there by reducing the static
memory overhead.
One example is of Page Owner, default value of STACK_HASH_SIZE lead
stack depot to consume 8MB of static memory. Making it configurable
and use lower value helps to enable features like CONFIG_PAGE_OWNER
without any significant overhead.
Suggested-by: Minchan Kim <minc...@kernel.org>
Signed-off-by: Yogesh Lal <y...@codeaurora.org>
Signed-off-by: Vijayanand Jitta <vji...@codeaurora.org>
---
lib/stackdepot.c | 31 +++++++++++++++++++++++++++----
1 file changed, 27 insertions(+), 4 deletions(-)
diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index 81c69c0..e0eebfd 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -30,6 +30,7 @@
#include <linux/stackdepot.h>
#include <linux/string.h>
#include <linux/types.h>
+#include <linux/vmalloc.h>
#define DEPOT_STACK_BITS (sizeof(depot_stack_handle_t) * 8)
@@ -141,14 +142,36 @@ static struct stack_record *depot_alloc_stack(unsigned
long *entries, int size,
return stack;
}
-#define STACK_HASH_ORDER 20
-#define STACK_HASH_SIZE (1L << STACK_HASH_ORDER)
+#define MAX_STACK_HASH_ORDER 20
+#define MAX_STACK_HASH_SIZE (1L << MAX_STACK_HASH_ORDER)
+#define STACK_HASH_SIZE (1L << stack_hash_order)
#define STACK_HASH_MASK (STACK_HASH_SIZE - 1)
#define STACK_HASH_SEED 0x9747b28c
-static struct stack_record *stack_table[STACK_HASH_SIZE] = {
- [0 ... STACK_HASH_SIZE - 1] = NULL
+static unsigned int stack_hash_order = 20;
+static struct stack_record *stack_table_def[MAX_STACK_HASH_SIZE] __initdata = {
+ [0 ... MAX_STACK_HASH_SIZE - 1] = NULL
};
+static struct stack_record **stack_table __refdata = stack_table_def;
+
+static int __init setup_stack_hash_order(char *str)
+{
+ kstrtouint(str, 0, &stack_hash_order);
+ if (stack_hash_order > MAX_STACK_HASH_ORDER)
+ stack_hash_order = MAX_STACK_HASH_ORDER;
+ return 0;
+}
+early_param("stack_hash_order", setup_stack_hash_order);
+
+static int __init init_stackdepot(void)
+{
+ size_t size = (STACK_HASH_SIZE * sizeof(struct stack_record *));
+
+ stack_table = vmalloc(size);
+ memcpy(stack_table, stack_table_def, size);
+ return 0;
+}
+early_initcall(init_stackdepot);
/* Calculate hash for a stack */
static inline u32 hash_stack(unsigned long *entries, unsigned int size)
--
2.7.4
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