X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fwaiter.c;h=aca88eb4db75ade4fa28b971d4616be68bd92742;hp=c5a2829408215784952d047e272c12682e291c23;hb=HEAD;hpb=287a512f2b868c16132b894a8143a5faf0379ca8

diff --git a/src/common/waiter.c b/src/common/waiter.c
deleted file mode 100644
index c5a282940..000000000
--- a/src/common/waiter.c
+++ /dev/null
@@ -1,124 +0,0 @@
-/*
- * Copyright (C) 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *               2017 - Jérémie Galarneau <jeremie.galarneau@efficios.com>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU Lesser General Public License, version 2.1 only,
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
- * for more details.
- *
- * You should have received a copy of the GNU Lesser General Public License
- * along with this program; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * This code is originally adapted from userspace-rcu's urcu-wait.h
- */
-
-#include "waiter.h"
-#include <urcu/uatomic.h>
-#include <urcu/futex.h>
-#include <assert.h>
-#include "error.h"
-#include <poll.h>
-
-/*
- * Number of busy-loop attempts before waiting on futex.
- */
-#define WAIT_ATTEMPTS 1000
-
-enum waiter_state {
-	/* WAITER_WAITING is compared directly (futex compares it). */
-	WAITER_WAITING =	0,
-	/* non-zero are used as masks. */
-	WAITER_WOKEN_UP =	(1 << 0),
-	WAITER_RUNNING =	(1 << 1),
-	WAITER_TEARDOWN =	(1 << 2),
-};
-
-LTTNG_HIDDEN
-void lttng_waiter_init(struct lttng_waiter *waiter)
-{
-	cds_wfs_node_init(&waiter->wait_queue_node);
-	uatomic_set(&waiter->state, WAITER_WAITING);
-	cmm_smp_mb();
-}
-
-/*
- * User must init "waiter" before passing its memory to waker thread.
- */
-LTTNG_HIDDEN
-void lttng_waiter_wait(struct lttng_waiter *waiter)
-{
-	unsigned int i;
-
-	DBG("Beginning of waiter wait period");
-	/* Load and test condition before read state */
-	cmm_smp_rmb();
-	for (i = 0; i < WAIT_ATTEMPTS; i++) {
-		if (uatomic_read(&waiter->state) != WAITER_WAITING) {
-			goto skip_futex_wait;
-		}
-		caa_cpu_relax();
-	}
-	while (futex_noasync(&waiter->state, FUTEX_WAIT, WAITER_WAITING,
-			NULL, NULL, 0)) {
-		switch (errno) {
-		case EWOULDBLOCK:
-			/* Value already changed. */
-			goto skip_futex_wait;
-		case EINTR:
-			/* Retry if interrupted by signal. */
-			break;	/* Get out of switch. */
-		default:
-			/* Unexpected error. */
-			PERROR("futex_noasync");
-			abort();
-		}
-	}
-skip_futex_wait:
-
-	/* Tell waker thread than we are running. */
-	uatomic_or(&waiter->state, WAITER_RUNNING);
-
-	/*
-	 * Wait until waker thread lets us know it's ok to tear down
-	 * memory allocated for struct lttng_waiter.
-	 */
-	for (i = 0; i < WAIT_ATTEMPTS; i++) {
-		if (uatomic_read(&waiter->state) & WAITER_TEARDOWN) {
-			break;
-		}
-		caa_cpu_relax();
-	}
-	while (!(uatomic_read(&waiter->state) & WAITER_TEARDOWN)) {
-		poll(NULL, 0, 10);
-	}
-	assert(uatomic_read(&waiter->state) & WAITER_TEARDOWN);
-	DBG("End of waiter wait period");
-}
-
-/*
- * Note: lttng_waiter_wake needs waiter to stay allocated throughout its
- * execution. In this scheme, the waiter owns the node memory, and we only allow
- * it to free this memory when it sees the WAITER_TEARDOWN flag.
- */
-LTTNG_HIDDEN
-void lttng_waiter_wake_up(struct lttng_waiter *waiter)
-{
-	cmm_smp_mb();
-	assert(uatomic_read(&waiter->state) == WAITER_WAITING);
-	uatomic_set(&waiter->state, WAITER_WOKEN_UP);
-	if (!(uatomic_read(&waiter->state) & WAITER_RUNNING)) {
-		if (futex_noasync(&waiter->state, FUTEX_WAKE, 1,
-				NULL, NULL, 0) < 0) {
-			PERROR("futex_noasync");
-			abort();
-		}
-	}
-	/* Allow teardown of struct urcu_wait memory. */
-	uatomic_or(&waiter->state, WAITER_TEARDOWN);
-}