Commit b6a353d3 authored by Andrey Konovalov's avatar Andrey Konovalov Committed by Andrew Morton
Browse files

lib/stackdepot: rename next_pool_required to new_pool_required 

Rename next_pool_required to new_pool_required.

This a purely code readability change: the following patch will change
stack depot to store the pointer to the new pool in a separate variable,
and "new" seems like a more logical name.

Link: https://lkml.kernel.org/r/fd7cd6c6eb250c13ec5d2009d75bb4ddd1470db9.1700502145.git.andreyknvl@google.com


Signed-off-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Reviewed-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 94b7d328

lib/stackdepot.c

+24 −25
Original line number Diff line number Diff line
@@ -93,12 +93,11 @@ static size_t pool_offset; 
static DEFINE_RAW_SPINLOCK(pool_lock);

/*

 * Stack depot tries to keep an extra pool allocated even before it runs out

 * of space in the currently used pool.

 * This flag marks that this next extra pool needs to be allocated and

 * initialized. It has the value 0 when either the next pool is not yet

 * initialized or the limit on the number of pools is reached.

 * of space in the currently used pool. This flag marks whether this extra pool

 * needs to be allocated. It has the value 0 when either an extra pool is not

 * yet allocated or if the limit on the number of pools is reached.

 */

static int next_pool_required = 1;

static int new_pool_required = 1;



static int __init disable_stack_depot(char *str)

{
@@ -225,20 +224,20 @@ int stack_depot_init(void) 
}

EXPORT_SYMBOL_GPL(stack_depot_init);



/* Keeps the preallocated memory to be used for the next stack depot pool. */

static void depot_keep_next_pool(void **prealloc)

/* Keeps the preallocated memory to be used for a new stack depot pool. */

static void depot_keep_new_pool(void **prealloc)

{

	/*

	 * If the next pool is already saved or the maximum number of

	 * If a new pool is already saved or the maximum number of

	 * pools is reached, do not use the preallocated memory.

	 * Access next_pool_required non-atomically, as there are no concurrent

	 * Access new_pool_required non-atomically, as there are no concurrent

	 * write accesses to this variable.

	 */

	if (!next_pool_required)

	if (!new_pool_required)

		return;



	/*

	 * Use the preallocated memory for the next pool

	 * Use the preallocated memory for the new pool

	 * as long as we do not exceed the maximum number of pools.

	 */

	if (pool_index + 1 < DEPOT_MAX_POOLS) {
@@ -247,13 +246,13 @@ static void depot_keep_next_pool(void **prealloc) 
	}



	/*

	 * At this point, either the next pool is kept or the maximum

	 * At this point, either a new pool is kept or the maximum

	 * number of pools is reached. In either case, take note that

	 * keeping another pool is not required.

	 * smp_store_release() pairs with smp_load_acquire() in

	 * stack_depot_save().

	 */

	smp_store_release(&next_pool_required, 0);

	smp_store_release(&new_pool_required, 0);

}



/* Updates references to the current and the next stack depot pools. */
@@ -268,7 +267,7 @@ static bool depot_update_pools(size_t required_size, void **prealloc) 
		}



		/*

		 * Move on to the next pool.

		 * Move on to the new pool.

		 * WRITE_ONCE() pairs with potential concurrent read in

		 * stack_depot_fetch().

		 */
@@ -277,12 +276,12 @@ static bool depot_update_pools(size_t required_size, void **prealloc) 


		/*

		 * If the maximum number of pools is not reached, take note

		 * that the next pool needs to be initialized.

		 * that yet another new pool needs to be allocated.

		 * smp_store_release() pairs with smp_load_acquire() in

		 * stack_depot_save().

		 */

		if (pool_index + 1 < DEPOT_MAX_POOLS)

			smp_store_release(&next_pool_required, 1);

			smp_store_release(&new_pool_required, 1);

	}



	/* Check if the current pool is not yet allocated. */
@@ -293,9 +292,9 @@ static bool depot_update_pools(size_t required_size, void **prealloc) 
		return true;

	}



	/* Otherwise, try using the preallocated memory for the next pool. */

	/* Otherwise, try using the preallocated memory for a new pool. */

	if (*prealloc)

		depot_keep_next_pool(prealloc);

		depot_keep_new_pool(prealloc);

	return true;

}
@@ -306,7 +305,7 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) 
	struct stack_record *stack;

	size_t required_size = DEPOT_STACK_RECORD_SIZE;



	/* Update current and next pools if required and possible. */

	/* Update current and new pools if required and possible. */

	if (!depot_update_pools(required_size, prealloc))

		return NULL;
@@ -438,13 +437,13 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, 
		goto exit;



	/*

	 * Check if another stack pool needs to be initialized. If so, allocate

	 * the memory now - we won't be able to do that under the lock.

	 * Check if another stack pool needs to be allocated. If so, allocate

	 * the memory now: we won't be able to do that under the lock.

	 *

	 * smp_load_acquire() pairs with smp_store_release() in

	 * depot_update_pools() and depot_keep_next_pool().

	 * depot_update_pools() and depot_keep_new_pool().

	 */

	if (unlikely(can_alloc && smp_load_acquire(&next_pool_required))) {

	if (unlikely(can_alloc && smp_load_acquire(&new_pool_required))) {

		/*

		 * Zero out zone modifiers, as we don't have specific zone

		 * requirements. Keep the flags related to allocation in atomic
@@ -477,9 +476,9 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, 
	} else if (prealloc) {

		/*

		 * Stack depot already contains this stack trace, but let's

		 * keep the preallocated memory for the future.

		 * keep the preallocated memory for future.

		 */

		depot_keep_next_pool(&prealloc);

		depot_keep_new_pool(&prealloc);

	}



	raw_spin_unlock_irqrestore(&pool_lock, flags);