callout: retire callout_async_drain()

This function was used only in TCP before 446ccdd08e2a.  It was born in
pain in 2016 to plug different complex panics in TCP timers.  It wasn't
warmly accepted in phabricator by all of the reviewers and my recollection
of overall agreement was that "if you need this KPI, then you'd better fix
your code to not need it".  However, the function served its duty well all
the way to FreeBSD 14.  But now that TCP doesn't need it anymore, let's
retire it to reduce complexity of callout code and also to avoid its
further use.

Reviewed by:		jhb, markj, kib, rrs
Differential Revision:	https://reviews.freebsd.org/D43546

2 files changed, 0 insertions, 314 deletions

diff --git a/sys/tests/callout_test.h b/sys/tests/callout_test.h
deleted file mode 100644
index 60a02f0c7b56..000000000000
--- a/sys/tests/callout_test.h
+++ /dev/null
@@ -1,32 +0,0 @@
-#ifndef __callout_test_h__
-#define __callout_test_h__
-/*-
- * Copyright (c) 2015 Netflix, Inc.
- * 
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. 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.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
- *
- */
-struct callout_test {
-	int number_of_callouts;
-	int test_number;
-};
-#endif
diff --git a/sys/tests/callout_test/callout_test.c b/sys/tests/callout_test/callout_test.c
deleted file mode 100644
index 059d6a728fb6..000000000000
--- a/sys/tests/callout_test/callout_test.c
+++ /dev/null
@@ -1,282 +0,0 @@
-/*-
- * Copyright (c) 2015 Netflix, Inc.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. 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.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 <sys/param.h>
-#include <sys/systm.h>
-#include <sys/conf.h>
-#include <sys/cpuctl.h>
-#include <sys/fcntl.h>
-#include <sys/ioccom.h>
-#include <sys/kernel.h>
-#include <sys/libkern.h>
-#include <sys/malloc.h>
-#include <sys/module.h>
-#include <sys/mutex.h>
-#include <sys/pcpu.h>
-#include <sys/pmckern.h>
-#include <sys/priv.h>
-#include <sys/proc.h>
-#include <sys/queue.h>
-#include <sys/sched.h>
-#include <sys/smp.h>
-#include <sys/sysctl.h>
-#include <sys/uio.h>
-#include <tests/kern_testfrwk.h>
-#include <tests/callout_test.h>
-#include <machine/cpu.h>
-
-MALLOC_DEFINE(M_CALLTMP, "Temp callout Memory", "CalloutTest");
-
-struct callout_run {
-	struct mtx lock;
-	struct callout *co_array;
-	int co_test;
-	int co_number_callouts;
-	int co_return_npa;
-	int co_completed;
-	int callout_waiting;
-	int drain_calls;
-	int cnt_zero;
-	int cnt_one;
-	int index;
-};
-
-static struct callout_run *comaster[MAXCPU];
-
-uint64_t callout_total = 0;
-
-static void execute_the_co_test(struct callout_run *rn);
-
-static void
-co_saydone(void *arg)
-{
-	struct callout_run *rn;
-
-	rn = (struct callout_run *)arg;
-	printf("The callout test is now complete for thread %d\n",
-	    rn->index);
-	printf("number_callouts:%d\n",
-	    rn->co_number_callouts);
-	printf("Callouts that bailed (Not PENDING or ACTIVE cleared):%d\n",
-	    rn->co_return_npa);
-	printf("Callouts that completed:%d\n", rn->co_completed);
-	printf("Drain calls:%d\n", rn->drain_calls);
-	printf("Zero returns:%d non-zero:%d\n",
-	    rn->cnt_zero,
-	    rn->cnt_one);
-
-}
-
-static void
-drainit(void *arg)
-{
-	struct callout_run *rn;
-
-	rn = (struct callout_run *)arg;
-	mtx_lock(&rn->lock);
-	rn->drain_calls++;
-	mtx_unlock(&rn->lock);
-}
-
-static void
-test_callout(void *arg)
-{
-	struct callout_run *rn;
-	int cpu;
-
-	critical_enter();
-	cpu = curcpu;
-	critical_exit();
-	rn = (struct callout_run *)arg;
-	atomic_add_int(&rn->callout_waiting, 1);
-	mtx_lock(&rn->lock);
-	if (callout_pending(&rn->co_array[cpu]) ||
-	    !callout_active(&rn->co_array[cpu])) {
-		rn->co_return_npa++;
-		atomic_subtract_int(&rn->callout_waiting, 1);
-		mtx_unlock(&rn->lock);
-		return;
-	}
-	callout_deactivate(&rn->co_array[cpu]);
-	rn->co_completed++;
-	mtx_unlock(&rn->lock);
-	atomic_subtract_int(&rn->callout_waiting, 1);
-}
-
-void
-execute_the_co_test(struct callout_run *rn)
-{
-	int i, ret, cpu;
-	uint32_t tk_s, tk_e, tk_d;
-
-	mtx_lock(&rn->lock);
-	rn->callout_waiting = 0;
-	for (i = 0; i < rn->co_number_callouts; i++) {
-		if (rn->co_test == 1) {
-			/* start all on spread out cpu's */
-			cpu = i % mp_ncpus;
-			callout_reset_sbt_on(&rn->co_array[i], 3, 0, test_callout, rn,
-			    cpu, 0);
-		} else {
-			/* Start all on the same CPU */
-			callout_reset_sbt_on(&rn->co_array[i], 3, 0, test_callout, rn,
-			    rn->index, 0);
-		}
-	}
-	tk_s = ticks;
-	while (rn->callout_waiting != rn->co_number_callouts) {
-		cpu_spinwait();
-		tk_e = ticks;
-		tk_d = tk_e - tk_s;
-		if (tk_d > 100) {
-			break;
-		}
-	}
-	/* OK everyone is waiting and we have the lock */
-	for (i = 0; i < rn->co_number_callouts; i++) {
-		ret = callout_async_drain(&rn->co_array[i], drainit);
-		if (ret) {
-			rn->cnt_one++;
-		} else {
-			rn->cnt_zero++;
-		}
-	}
-	rn->callout_waiting -= rn->cnt_one;
-	mtx_unlock(&rn->lock);
-	/* Now wait until all are done */
-	tk_s = ticks;
-	while (rn->callout_waiting > 0) {
-		cpu_spinwait();
-		tk_e = ticks;
-		tk_d = tk_e - tk_s;
-		if (tk_d > 100) {
-			break;
-		}
-	}
-	co_saydone((void *)rn);
-}
-
-
-static void
-run_callout_test(struct kern_test *test)
-{
-	struct callout_test *u;
-	size_t sz;
-	int i;
-	struct callout_run *rn;
-	int index = test->tot_threads_running;
-
-	u = (struct callout_test *)test->test_options;
-	if (comaster[index] == NULL) {
-		rn = comaster[index] = malloc(sizeof(struct callout_run), M_CALLTMP, M_WAITOK);
-		memset(comaster[index], 0, sizeof(struct callout_run));
-		mtx_init(&rn->lock, "callouttest", NULL, MTX_DUPOK);
-		rn->index = index;
-	} else {
-		rn = comaster[index];
-		rn->co_number_callouts = rn->co_return_npa = 0;
-		rn->co_completed = rn->callout_waiting = 0;
-		rn->drain_calls = rn->cnt_zero = rn->cnt_one = 0;
-		if (rn->co_array) {
-			free(rn->co_array, M_CALLTMP);
-			rn->co_array = NULL;
-		}
-	}
-	rn->co_number_callouts = u->number_of_callouts;
-	rn->co_test = u->test_number;
-	sz = sizeof(struct callout) * rn->co_number_callouts;
-	rn->co_array = malloc(sz, M_CALLTMP, M_WAITOK);
-	for (i = 0; i < rn->co_number_callouts; i++) {
-		callout_init(&rn->co_array[i], CALLOUT_MPSAFE);
-	}
-	execute_the_co_test(rn);
-}
-
-int callout_test_is_loaded = 0;
-
-static void
-cocleanup(void)
-{
-	int i;
-
-	for (i = 0; i < MAXCPU; i++) {
-		if (comaster[i]) {
-			if (comaster[i]->co_array) {
-				free(comaster[i]->co_array, M_CALLTMP);
-				comaster[i]->co_array = NULL;
-			}
-			free(comaster[i], M_CALLTMP);
-			comaster[i] = NULL;
-		}
-	}
-}
-
-static int
-callout_test_modevent(module_t mod, int type, void *data)
-{
-	int err = 0;
-
-	switch (type) {
-	case MOD_LOAD:
-		err = kern_testframework_register("callout_test",
-		    run_callout_test);
-		if (err) {
-			printf("Can't load callout_test err:%d returned\n",
-			    err);
-		} else {
-			memset(comaster, 0, sizeof(comaster));
-			callout_test_is_loaded = 1;
-		}
-		break;
-	case MOD_QUIESCE:
-		err = kern_testframework_deregister("callout_test");
-		if (err == 0) {
-			callout_test_is_loaded = 0;
-			cocleanup();
-		}
-		break;
-	case MOD_UNLOAD:
-		if (callout_test_is_loaded) {
-			err = kern_testframework_deregister("callout_test");
-			if (err == 0) {
-				cocleanup();
-				callout_test_is_loaded = 0;
-			}
-		}
-		break;
-	default:
-		return (EOPNOTSUPP);
-	}
-	return (err);
-}
-
-static moduledata_t callout_test_mod = {
-	.name = "callout_test",
-	.evhand = callout_test_modevent,
-	.priv = 0
-};
-
-MODULE_DEPEND(callout_test, kern_testframework, 1, 1, 1);
-DECLARE_MODULE(callout_test, callout_test_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);