#include "urcu/tls-compat.h"
#include "urcu-die.h"
+#include "urcu-wait.h"
/* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
#undef _LGPL_SOURCE
static CDS_LIST_HEAD(registry);
-/*
- * Number of busy-loop attempts before waiting on futex for grace period
- * batching.
- */
-#define RCU_AWAKE_ATTEMPTS 1000
-
-enum adapt_wakeup_state {
- /* AWAKE_WAITING is compared directly (futex compares it). */
- AWAKE_WAITING = 0,
- /* non-zero are used as masks. */
- AWAKE_WAKEUP = (1 << 0),
- AWAKE_AWAKENED = (1 << 1),
- AWAKE_TEARDOWN = (1 << 2),
-};
-
struct gp_waiters_thread {
struct cds_wfs_node node;
- int32_t wait_futex;
+ struct urcu_wait wait;
};
/*
NULL, NULL, 0);
}
-/*
- * Note: urcu_adaptative_wake_up needs "value" to stay allocated
- * throughout its execution. In this scheme, the waiter owns the futex
- * memory, and we only allow it to free this memory when it receives the
- * AWAKE_TEARDOWN flag.
- */
-static void urcu_adaptative_wake_up(int32_t *value)
-{
- cmm_smp_mb();
- assert(uatomic_read(value) == AWAKE_WAITING);
- uatomic_set(value, AWAKE_WAKEUP);
- if (!(uatomic_read(value) & AWAKE_AWAKENED))
- futex_noasync(value, FUTEX_WAKE, 1, NULL, NULL, 0);
- /* Allow teardown of "value" memory. */
- uatomic_or(value, AWAKE_TEARDOWN);
-}
-
-/*
- * Caller must initialize "value" to AWAKE_WAITING before passing its
- * memory to waker thread.
- */
-static void urcu_adaptative_busy_wait(int32_t *value)
-{
- unsigned int i;
-
- /* Load and test condition before read futex */
- cmm_smp_rmb();
- for (i = 0; i < RCU_AWAKE_ATTEMPTS; i++) {
- if (uatomic_read(value) != AWAKE_WAITING)
- goto skip_futex_wait;
- caa_cpu_relax();
- }
- futex_noasync(value, FUTEX_WAIT, AWAKE_WAITING, NULL, NULL, 0);
-skip_futex_wait:
-
- /* Tell waker thread than we are awakened. */
- uatomic_or(value, AWAKE_AWAKENED);
-
- /*
- * Wait until waker thread lets us know it's ok to tear down
- * memory allocated for value.
- */
- for (i = 0; i < RCU_AWAKE_ATTEMPTS; i++) {
- if (uatomic_read(value) & AWAKE_TEARDOWN)
- break;
- caa_cpu_relax();
- }
- while (!(uatomic_read(value) & AWAKE_TEARDOWN))
- poll(NULL, 0, 10);
- assert(uatomic_read(value) & AWAKE_TEARDOWN);
-}
-
static void wait_for_readers(struct cds_list_head *input_readers,
struct cds_list_head *cur_snap_readers,
struct cds_list_head *qsreaders)
* if we are the first thread added into the stack.
*/
cds_wfs_node_init(&gp_waiters_thread.node);
- gp_waiters_thread.wait_futex = AWAKE_WAITING;
+ urcu_wait_init(&gp_waiters_thread.wait);
if (cds_wfs_push(&gp_waiters, &gp_waiters_node) != 0) {
/* Not first in stack: will be awakened by another thread. */
- urcu_adaptative_busy_wait(&gp_waiters_thread.wait_futex);
+ urcu_adaptative_busy_wait(&gp_waiters_thread.wait);
goto gp_end;
}
struct gp_waiters_thread, node);
if (wt == &gp_waiters_thread)
continue;
- urcu_adaptative_wake_up(&wt->wait_futex);
+ urcu_adaptative_wake_up(&wt->wait);
}
gp_end:
* if we are the first thread added into the stack.
*/
cds_wfs_node_init(&gp_waiters_thread.node);
- gp_waiters_thread.wait_futex = AWAKE_WAITING;
+ urcu_wait_init(&gp_waiters_thread.wait);
if (cds_wfs_push(&gp_waiters, &gp_waiters_thread.node) != 0) {
/* Not first in stack: will be awakened by another thread. */
- urcu_adaptative_busy_wait(&gp_waiters_thread.wait_futex);
+ urcu_adaptative_busy_wait(&gp_waiters_thread.wait);
goto gp_end;
}
struct gp_waiters_thread, node);
if (wt == &gp_waiters_thread)
continue;
- urcu_adaptative_wake_up(&wt->wait_futex);
+ urcu_adaptative_wake_up(&wt->wait);
}
gp_end: