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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2011, 2019 by Delphix. All rights reserved.
* Copyright (c) 2011 Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2017, Intel Corporation.
*/
#include <sys/sysmacros.h>
#include <sys/zio.h>
#include <sys/zio_impl.h>
#include <sys/time.h>
#include <sys/trace_zfs.h>
void
zio_delay_interrupt(zio_t *zio)
{
/*
* The timeout_generic() function isn't defined in userspace, so
* rather than trying to implement the function, the zio delay
* functionality has been disabled for userspace builds.
*/
#ifdef _KERNEL
/*
* If io_target_timestamp is zero, then no delay has been registered
* for this IO, thus jump to the end of this function and "skip" the
* delay; issuing it directly to the zio layer.
*/
if (zio->io_target_timestamp != 0) {
hrtime_t now = gethrtime();
if (now >= zio->io_target_timestamp) {
/*
* This IO has already taken longer than the target
* delay to complete, so we don't want to delay it
* any longer; we "miss" the delay and issue it
* directly to the zio layer. This is likely due to
* the target latency being set to a value less than
* the underlying hardware can satisfy (e.g. delay
* set to 1ms, but the disks take 10ms to complete an
* IO request).
*/
DTRACE_PROBE2(zio__delay__miss, zio_t *, zio,
hrtime_t, now);
zio_interrupt(zio);
} else {
taskqid_t tid;
hrtime_t diff = zio->io_target_timestamp - now;
clock_t expire_at_tick = ddi_get_lbolt() +
NSEC_TO_TICK(diff);
DTRACE_PROBE3(zio__delay__hit, zio_t *, zio,
hrtime_t, now, hrtime_t, diff);
if (NSEC_TO_TICK(diff) == 0) {
/* Our delay is less than a jiffy - just spin */
zfs_sleep_until(zio->io_target_timestamp);
zio_interrupt(zio);
} else {
/*
* Use taskq_dispatch_delay() in the place of
* OpenZFS's timeout_generic().
*/
tid = taskq_dispatch_delay(system_taskq,
(task_func_t *)zio_interrupt,
zio, TQ_NOSLEEP, expire_at_tick);
if (tid == TASKQID_INVALID) {
/*
* Couldn't allocate a task. Just
* finish the zio without a delay.
*/
zio_interrupt(zio);
}
}
}
return;
}
#endif
DTRACE_PROBE1(zio__delay__skip, zio_t *, zio);
zio_interrupt(zio);
}
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