diff options
| -rw-r--r-- | lib/stackdepot.c | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/lib/stackdepot.c b/lib/stackdepot.c index c4bc198c3d93..4df162a84bfe 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -96,8 +96,14 @@ static int pool_index; static size_t pool_offset; /* Lock that protects the variables above. */ static DEFINE_RAW_SPINLOCK(pool_lock); -/* Whether the next pool is initialized. */ -static int next_pool_inited; +/* + * 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. + */ +static int next_pool_required = 1; static int __init disable_stack_depot(char *str) { @@ -222,10 +228,12 @@ EXPORT_SYMBOL_GPL(stack_depot_init); static void depot_init_pool(void **prealloc) { /* + * If the next pool is already initialized or the maximum number of + * pools is reached, do not use the preallocated memory. * smp_load_acquire() here pairs with smp_store_release() below and * in depot_alloc_stack(). */ - if (smp_load_acquire(&next_pool_inited)) + if (!smp_load_acquire(&next_pool_required)) return; /* Check if the current pool is not yet allocated. */ @@ -243,10 +251,13 @@ static void depot_init_pool(void **prealloc) *prealloc = NULL; } /* + * At this point, either the next pool is initialized or the + * maximum number of pools is reached. In either case, take + * note that initializing another pool is not required. * This smp_store_release pairs with smp_load_acquire() above * and in stack_depot_save(). */ - smp_store_release(&next_pool_inited, 1); + smp_store_release(&next_pool_required, 0); } } @@ -271,11 +282,13 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) pool_index++; pool_offset = 0; /* + * If the maximum number of pools is not reached, take note + * that the next pool needs to initialized. * smp_store_release() here pairs with smp_load_acquire() in * stack_depot_save() and depot_init_pool(). */ if (pool_index + 1 < DEPOT_MAX_POOLS) - smp_store_release(&next_pool_inited, 0); + smp_store_release(&next_pool_required, 1); } /* Assign the preallocated memory to a pool if required. */ @@ -406,14 +419,13 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, goto exit; /* - * Check if the current or the next stack pool need to be initialized. - * If so, allocate the memory - we won't be able to do that under the - * lock. + * 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. * * The smp_load_acquire() here pairs with smp_store_release() to * |next_pool_inited| in depot_alloc_stack() and depot_init_pool(). */ - if (unlikely(can_alloc && !smp_load_acquire(&next_pool_inited))) { + if (unlikely(can_alloc && smp_load_acquire(&next_pool_required))) { /* * Zero out zone modifiers, as we don't have specific zone * requirements. Keep the flags related to allocation in atomic |