Messages in this thread | | | From | Dmitry Vyukov <> | Date | Thu, 17 Dec 2020 11:27:32 +0100 | Subject | Re: [PATCH v3] lib: stackdepot: Add support to configure STACK_HASH_SIZE |
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On Thu, Dec 17, 2020 at 11:25 AM Dmitry Vyukov <dvyukov@google.com> wrote: > > On Thu, Dec 10, 2020 at 6:04 AM <vjitta@codeaurora.org> wrote: > > > > From: Yogesh Lal <ylal@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 <minchan@kernel.org> > > Signed-off-by: Yogesh Lal <ylal@codeaurora.org> > > Signed-off-by: Vijayanand Jitta <vjitta@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)
Can interrupts happen here?
> > + 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); > > Can interrupts happen at this point in time? If yes, they can > use/modify stack_table_def concurrently. > > > + 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 > > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
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