lib: stackdepot: add support to configure STACK_HASH_SIZE

Use CONFIG_STACK_HASH_ORDER to configure STACK_HASH_SIZE. Aim is to have configurable value for STACK_HASH_SIZE, so depend on use case one can configure it. One example is of Page Owner, CONFIG_PAGE_OWNER works only if page_owner=on via kernel parameter on CONFIG_PAGE_OWNER configured system. Thus, unless admin enable it via command line option, the stackdepot will just waste 8M memory without any customer. Making it configurable and use lower value helps to enable features like CONFIG_PAGE_OWNER without any significant overhead. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Yogesh Lal <[email protected]> Signed-off-by: Vinayak Menon <[email protected]> Signed-off-by: Vijayanand Jitta <[email protected]> Reviewed-by: Minchan Kim <[email protected]> Reviewed-by: Alexander Potapenko <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
josf · Feb 26, 2021 · d262093 · d262093
1 parent a28a6e8
commit d262093
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/lib/Kconfig b/lib/Kconfig
@@ -651,6 +651,15 @@ config STACKDEPOT
 	bool
 	select STACKTRACE
 
+config STACK_HASH_ORDER
+	int "stack depot hash size (12 => 4KB, 20 => 1024KB)"
+	range 12 20
+	default 20
+	depends on STACKDEPOT
+	help
+	 Select the hash size as a power of 2 for the stackdepot hash table.
+	 Choose a lower value to reduce the memory impact.
+
 config SBITMAP
 	bool
 

diff --git a/lib/stackdepot.c b/lib/stackdepot.c
@@ -141,8 +141,7 @@ 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 STACK_HASH_SIZE (1L << CONFIG_STACK_HASH_ORDER)
 #define STACK_HASH_MASK (STACK_HASH_SIZE - 1)
 #define STACK_HASH_SEED 0x9747b28c