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Diffstat (limited to 'src/core/support/stack_lockfree.c')
-rw-r--r--src/core/support/stack_lockfree.c35
1 files changed, 35 insertions, 0 deletions
diff --git a/src/core/support/stack_lockfree.c b/src/core/support/stack_lockfree.c
index 2844330379..f24e272207 100644
--- a/src/core/support/stack_lockfree.c
+++ b/src/core/support/stack_lockfree.c
@@ -72,6 +72,11 @@ typedef union lockfree_node {
struct gpr_stack_lockfree {
lockfree_node *entries;
lockfree_node head; /* An atomic entry describing curr head */
+
+#ifndef NDEBUG
+ /* Bitmap of pushed entries to check for double-push or pop */
+ gpr_atm pushed[(INVALID_ENTRY_INDEX+1)/(8*sizeof(gpr_atm))];
+#endif
};
gpr_stack_lockfree *gpr_stack_lockfree_create(int entries) {
@@ -86,6 +91,9 @@ gpr_stack_lockfree *gpr_stack_lockfree_create(int entries) {
/* Clear out all entries */
memset(stack->entries, 0, entries * sizeof(stack->entries[0]));
memset(&stack->head, 0, sizeof(stack->head));
+#ifndef NDEBUG
+ memset(&stack->pushed, 0, sizeof(stack->pushed));
+#endif
/* Point the head at reserved dummy entry */
stack->head.contents.index = INVALID_ENTRY_INDEX;
@@ -106,6 +114,19 @@ int gpr_stack_lockfree_push(gpr_stack_lockfree *stack, int entry) {
/* Also post-increment the aba_ctr */
newhead.contents.aba_ctr = stack->entries[entry].contents.aba_ctr++;
+#ifndef NDEBUG
+ /* Check for double push */
+ {
+ int pushed_index = entry / (8*sizeof(gpr_atm));
+ int pushed_bit = entry % (8*sizeof(gpr_atm));
+ gpr_atm old_val;
+
+ old_val = gpr_atm_no_barrier_fetch_add(&stack->pushed[pushed_index],
+ (gpr_atm)(1UL << pushed_bit));
+ GPR_ASSERT((old_val & (1UL<<pushed_bit)) == 0);
+ }
+#endif
+
do {
/* Atomically get the existing head value for use */
head.atm = gpr_atm_no_barrier_load(&(stack->head.atm));
@@ -119,6 +140,7 @@ int gpr_stack_lockfree_push(gpr_stack_lockfree *stack, int entry) {
int gpr_stack_lockfree_pop(gpr_stack_lockfree *stack) {
lockfree_node head;
lockfree_node newhead;
+
do {
head.atm = gpr_atm_acq_load(&(stack->head.atm));
if (head.contents.index == INVALID_ENTRY_INDEX) {
@@ -128,5 +150,18 @@ int gpr_stack_lockfree_pop(gpr_stack_lockfree *stack) {
gpr_atm_no_barrier_load(&(stack->entries[head.contents.index].atm));
} while (!gpr_atm_no_barrier_cas(&(stack->head.atm), head.atm, newhead.atm));
+#ifndef NDEBUG
+ /* Check for valid pop */
+ {
+ int pushed_index = head.contents.index / (8*sizeof(gpr_atm));
+ int pushed_bit = head.contents.index % (8*sizeof(gpr_atm));
+ gpr_atm old_val;
+
+ old_val = gpr_atm_no_barrier_fetch_add(&stack->pushed[pushed_index],
+ -(gpr_atm)(1UL << pushed_bit));
+ GPR_ASSERT((old_val & (1UL<<pushed_bit)) != 0);
+ }
+#endif
+
return head.contents.index;
}