Commit 8151c7a3 authored by Oscar Salvador's avatar Oscar Salvador Committed by Andrew Morton
Browse files

lib/stackdepot: move stack_record struct definition into the header 

In order to move the heavy lifting into page_owner code, this one needs to
have access to the stack_record structure, which right now sits in
lib/stackdepot.c.  Move it to the stackdepot.h header so page_owner can
access stack_record's struct fields.

Link: https://lkml.kernel.org/r/20240215215907.20121-3-osalvador@suse.de


Signed-off-by: default avatarOscar Salvador <osalvador@suse.de>
Reviewed-by: default avatarMarco Elver <elver@google.com>
Reviewed-by: default avatarVlastimil Babka <vbabka@suse.cz>
Acked-by: default avatarAndrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 3ee34eab

include/linux/stackdepot.h

+47 −0
Original line number Diff line number Diff line
@@ -30,6 +30,53 @@ typedef u32 depot_stack_handle_t; 
 */

#define STACK_DEPOT_EXTRA_BITS 5



#define DEPOT_HANDLE_BITS (sizeof(depot_stack_handle_t) * 8)



#define DEPOT_POOL_ORDER 2 /* Pool size order, 4 pages */

#define DEPOT_POOL_SIZE (1LL << (PAGE_SHIFT + DEPOT_POOL_ORDER))

#define DEPOT_STACK_ALIGN 4

#define DEPOT_OFFSET_BITS (DEPOT_POOL_ORDER + PAGE_SHIFT - DEPOT_STACK_ALIGN)

#define DEPOT_POOL_INDEX_BITS (DEPOT_HANDLE_BITS - DEPOT_OFFSET_BITS - \

			       STACK_DEPOT_EXTRA_BITS)



#ifdef CONFIG_STACKDEPOT

/* Compact structure that stores a reference to a stack. */

union handle_parts {

	depot_stack_handle_t handle;

	struct {

		/* pool_index is offset by 1 */

		u32 pool_index	: DEPOT_POOL_INDEX_BITS;

		u32 offset	: DEPOT_OFFSET_BITS;

		u32 extra	: STACK_DEPOT_EXTRA_BITS;

	};

};



struct stack_record {

	struct list_head hash_list;	/* Links in the hash table */

	u32 hash;			/* Hash in hash table */

	u32 size;			/* Number of stored frames */

	union handle_parts handle;	/* Constant after initialization */

	refcount_t count;

	union {

		unsigned long entries[CONFIG_STACKDEPOT_MAX_FRAMES];	/* Frames */

		struct {

			/*

			 * An important invariant of the implementation is to

			 * only place a stack record onto the freelist iff its

			 * refcount is zero. Because stack records with a zero

			 * refcount are never considered as valid, it is safe to

			 * union @entries and freelist management state below.

			 * Conversely, as soon as an entry is off the freelist

			 * and its refcount becomes non-zero, the below must not

			 * be accessed until being placed back on the freelist.

			 */

			struct list_head free_list;	/* Links in the freelist */

			unsigned long rcu_state;	/* RCU cookie */

		};

	};

};

#endif



typedef u32 depot_flags_t;



/*

lib/stackdepot.c

+0 −43
Original line number Diff line number Diff line
@@ -36,55 +36,12 @@ 
#include <linux/memblock.h>

#include <linux/kasan-enabled.h>



#define DEPOT_HANDLE_BITS (sizeof(depot_stack_handle_t) * 8)



#define DEPOT_POOL_ORDER 2 /* Pool size order, 4 pages */

#define DEPOT_POOL_SIZE (1LL << (PAGE_SHIFT + DEPOT_POOL_ORDER))

#define DEPOT_STACK_ALIGN 4

#define DEPOT_OFFSET_BITS (DEPOT_POOL_ORDER + PAGE_SHIFT - DEPOT_STACK_ALIGN)

#define DEPOT_POOL_INDEX_BITS (DEPOT_HANDLE_BITS - DEPOT_OFFSET_BITS - \

			       STACK_DEPOT_EXTRA_BITS)

#define DEPOT_POOLS_CAP 8192

/* The pool_index is offset by 1 so the first record does not have a 0 handle. */

#define DEPOT_MAX_POOLS \

	(((1LL << (DEPOT_POOL_INDEX_BITS)) - 1 < DEPOT_POOLS_CAP) ? \

	 (1LL << (DEPOT_POOL_INDEX_BITS)) - 1 : DEPOT_POOLS_CAP)



/* Compact structure that stores a reference to a stack. */

union handle_parts {

	depot_stack_handle_t handle;

	struct {

		u32 pool_index	: DEPOT_POOL_INDEX_BITS; /* pool_index is offset by 1 */

		u32 offset	: DEPOT_OFFSET_BITS;

		u32 extra	: STACK_DEPOT_EXTRA_BITS;

	};

};



struct stack_record {

	struct list_head hash_list;	/* Links in the hash table */

	u32 hash;			/* Hash in hash table */

	u32 size;			/* Number of stored frames */

	union handle_parts handle;	/* Constant after initialization */

	refcount_t count;

	union {

		unsigned long entries[CONFIG_STACKDEPOT_MAX_FRAMES];	/* Frames */

		struct {

			/*

			 * An important invariant of the implementation is to

			 * only place a stack record onto the freelist iff its

			 * refcount is zero. Because stack records with a zero

			 * refcount are never considered as valid, it is safe to

			 * union @entries and freelist management state below.

			 * Conversely, as soon as an entry is off the freelist

			 * and its refcount becomes non-zero, the below must not

			 * be accessed until being placed back on the freelist.

			 */

			struct list_head free_list;	/* Links in the freelist */

			unsigned long rcu_state;	/* RCU cookie */

		};

	};

};



static bool stack_depot_disabled;

static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_STACKDEPOT_ALWAYS_INIT);

static bool __stack_depot_early_init_passed __initdata;