aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/core/lib/support/stack_lockfree.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/core/lib/support/stack_lockfree.c')
-rw-r--r--src/core/lib/support/stack_lockfree.c152
1 files changed, 0 insertions, 152 deletions
diff --git a/src/core/lib/support/stack_lockfree.c b/src/core/lib/support/stack_lockfree.c
deleted file mode 100644
index dfbd3fb125..0000000000
--- a/src/core/lib/support/stack_lockfree.c
+++ /dev/null
@@ -1,152 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- * * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- * * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "src/core/lib/support/stack_lockfree.h"
-
-#include <stdlib.h>
-#include <string.h>
-
-#include <grpc/support/alloc.h>
-#include <grpc/support/atm.h>
-#include <grpc/support/log.h>
-#include <grpc/support/port_platform.h>
-
-/* The lockfree node structure is a single architecture-level
- word that allows for an atomic CAS to set it up. */
-struct lockfree_node_contents {
- /* next thing to look at. Actual index for head, next index otherwise */
- uint16_t index;
-#ifdef GPR_ARCH_64
- uint16_t pad;
- uint32_t aba_ctr;
-#else
-#ifdef GPR_ARCH_32
- uint16_t aba_ctr;
-#else
-#error Unsupported bit width architecture
-#endif
-#endif
-};
-
-/* Use a union to make sure that these are in the same bits as an atm word */
-typedef union lockfree_node {
- gpr_atm atm;
- struct lockfree_node_contents contents;
-} lockfree_node;
-
-/* make sure that entries aligned to 8-bytes */
-#define ENTRY_ALIGNMENT_BITS 3
-/* reserve this entry as invalid */
-#define INVALID_ENTRY_INDEX ((1 << 16) - 1)
-
-struct gpr_stack_lockfree {
- lockfree_node *entries;
- lockfree_node head; /* An atomic entry describing curr head */
-};
-
-gpr_stack_lockfree *gpr_stack_lockfree_create(size_t entries) {
- gpr_stack_lockfree *stack;
- stack = (gpr_stack_lockfree *)gpr_malloc(sizeof(*stack));
- /* Since we only allocate 16 bits to represent an entry number,
- * make sure that we are within the desired range */
- /* Reserve the highest entry number as a dummy */
- GPR_ASSERT(entries < INVALID_ENTRY_INDEX);
- stack->entries = (lockfree_node *)gpr_malloc_aligned(
- entries * sizeof(stack->entries[0]), ENTRY_ALIGNMENT_BITS);
- /* Clear out all entries */
- memset(stack->entries, 0, entries * sizeof(stack->entries[0]));
- memset(&stack->head, 0, sizeof(stack->head));
-
- GPR_ASSERT(sizeof(stack->entries->atm) == sizeof(stack->entries->contents));
-
- /* Point the head at reserved dummy entry */
- stack->head.contents.index = INVALID_ENTRY_INDEX;
-/* Fill in the pad and aba_ctr to avoid confusing memcheck tools */
-#ifdef GPR_ARCH_64
- stack->head.contents.pad = 0;
-#endif
- stack->head.contents.aba_ctr = 0;
- return stack;
-}
-
-void gpr_stack_lockfree_destroy(gpr_stack_lockfree *stack) {
- gpr_free_aligned(stack->entries);
- gpr_free(stack);
-}
-
-int gpr_stack_lockfree_push(gpr_stack_lockfree *stack, int entry) {
- lockfree_node head;
- lockfree_node newhead;
- lockfree_node curent;
- lockfree_node newent;
-
- /* First fill in the entry's index and aba ctr for new head */
- newhead.contents.index = (uint16_t)entry;
-#ifdef GPR_ARCH_64
- /* Fill in the pad to avoid confusing memcheck tools */
- newhead.contents.pad = 0;
-#endif
-
- /* Also post-increment the aba_ctr */
- curent.atm = gpr_atm_no_barrier_load(&stack->entries[entry].atm);
- newhead.contents.aba_ctr = ++curent.contents.aba_ctr;
- gpr_atm_no_barrier_store(&stack->entries[entry].atm, curent.atm);
-
- do {
- /* Atomically get the existing head value for use */
- head.atm = gpr_atm_no_barrier_load(&(stack->head.atm));
- /* Point to it */
- newent.atm = gpr_atm_no_barrier_load(&stack->entries[entry].atm);
- newent.contents.index = head.contents.index;
- gpr_atm_no_barrier_store(&stack->entries[entry].atm, newent.atm);
- } while (!gpr_atm_rel_cas(&(stack->head.atm), head.atm, newhead.atm));
- /* Use rel_cas above to make sure that entry index is set properly */
- return head.contents.index == INVALID_ENTRY_INDEX;
-}
-
-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) {
- return -1;
- }
- newhead.atm =
- gpr_atm_no_barrier_load(&(stack->entries[head.contents.index].atm));
-
- } while (!gpr_atm_no_barrier_cas(&(stack->head.atm), head.atm, newhead.atm));
-
- return head.contents.index;
-}