+ lib-stackdepot-add-support-to-configure-stack_hash_size.patch added to -mm tree

+ lib-stackdepot-add-support-to-configure-stack_hash_size.patch added to -mm tree

[akpm]

The patch titled
     Subject: lib: stackdepot: add support to configure STACK_HASH_SIZE
has been added to the -mm tree.  Its filename is
     lib-stackdepot-add-support-to-configure-stack_hash_size.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/lib-stackdepot-add-support-to-configure-stack_hash_size.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/lib-stackdepot-add-support-to-configure-stack_hash_size.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Yogesh Lal <ylal@codeaurora.org>
Subject: 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/1611749198-24316-1-git-send-email-vjitta@codeaurora.org
Signed-off-by: Yogesh Lal <ylal@codeaurora.org>
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/Kconfig      |    9 +++++++++
 lib/stackdepot.c |    3 +--
 2 files changed, 10 insertions(+), 2 deletions(-)

--- a/lib/Kconfig~lib-stackdepot-add-support-to-configure-stack_hash_size
+++ a/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
 
--- a/lib/stackdepot.c~lib-stackdepot-add-support-to-configure-stack_hash_size
+++ a/lib/stackdepot.c
@@ -141,8 +141,7 @@ static struct stack_record *depot_alloc_
 	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
 
_

Patches currently in -mm which might be from ylal@codeaurora.org are

lib-stackdepot-add-support-to-configure-stack_hash_size.patch

+ lib-stackdepot-add-support-to-configure-stack_hash_size.patch added to -mm tree

[akpm]

The patch titled
     Subject: lib: stackdepot: add support to configure STACK_HASH_SIZE
has been added to the -mm tree.  Its filename is
     lib-stackdepot-add-support-to-configure-stack_hash_size.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/lib-stackdepot-add-support-to-configure-stack_hash_size.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/lib-stackdepot-add-support-to-configure-stack_hash_size.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Yogesh Lal <ylal@codeaurora.org>
Subject: lib: stackdepot: add support to configure STACK_HASH_SIZE

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.

Link: https://lkml.kernel.org/r/1606365835-3242-1-git-send-email-vjitta@codeaurora.org
Suggested-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Yogesh Lal <ylal@codeaurora.org>
Signed-off-by: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Zhenhua Huang <zhenhuah@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/stackdepot.c |   27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

--- a/lib/stackdepot.c~lib-stackdepot-add-support-to-configure-stack_hash_size
+++ a/lib/stackdepot.c
@@ -141,14 +141,31 @@ static struct stack_record *depot_alloc_
 	return stack;
 }
 
-#define STACK_HASH_ORDER 20
-#define STACK_HASH_SIZE (1L << STACK_HASH_ORDER)
+static unsigned int stack_hash_order = 20;
+#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 struct stack_record **stack_table;
+
+static int __init setup_stack_hash_order(char *str)
+{
+	kstrtouint(str, 0, &stack_hash_order);
+	return 0;
+}
+early_param("stack_hash_order", setup_stack_hash_order);
+
+static int __init init_stackdepot(void)
+{
+	int i;
+
+	stack_table = kvmalloc(sizeof(struct stack_record *) * STACK_HASH_SIZE, GFP_KERNEL);
+	for (i = 0; i < STACK_HASH_SIZE; i++)
+		stack_table[i] = NULL;
+	return 0;
+}
+
+early_initcall(init_stackdepot);
 
 /* Calculate hash for a stack */
 static inline u32 hash_stack(unsigned long *entries, unsigned int size)
_

Patches currently in -mm which might be from ylal@codeaurora.org are

lib-stackdepot-add-support-to-configure-stack_hash_size.patch