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o Allow I/O scheduler to gather times on 32-bit systems. We do this by shifting the sbintime_t over by 8 bits and truncating to 32-bits. This gives us 8.24 time. This is sufficient both in range (256 seconds is about 128x what current users need) and precision (60ns easily meets the 1ms smallest bucket size measurements). 64-bit systems are unchanged. Centralize all the time math so it's easy to tweak tha range / precision tradeoffs in the future. o While I'm here, the I/O scheduler should be using periph_data rather than sim_data since it is operating on behalf of the periph. Differential Review: https://reviews.freebsd.org/D12119
103 lines
4.1 KiB
C
103 lines
4.1 KiB
C
/*-
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* CAM IO Scheduler Interface
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*
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* Copyright (c) 2015 Netflix, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification, immediately at the beginning of the file.
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* 2. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _CAM_CAM_IOSCHED_H
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#define _CAM_CAM_IOSCHED_H
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/* No user-serviceable parts in here. */
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#ifdef _KERNEL
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/* Forward declare all structs to keep interface thin */
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struct cam_iosched_softc;
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struct sysctl_ctx_list;
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struct sysctl_oid;
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union ccb;
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struct bio;
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/*
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* For 64-bit platforms, we know that uintptr_t is the same size as sbintime_t
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* so we can store values in it. For 32-bit systems, however, uintptr_t is only
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* 32-bits, so it won't fit. For those systems, store 24 bits of fraction and 8
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* bits of seconds. This allows us to measure an interval of up to ~256s, which
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* is ~200x what our current uses require. Provide some convenience functions to
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* get the time, subtract two times and convert back to sbintime_t in a safe way
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* that can be centralized.
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*/
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#ifdef __LP64__
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#define CAM_IOSCHED_TIME_SHIFT 0
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#else
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#define CAM_IOSCHED_TIME_SHIFT 8
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#endif
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static inline uintptr_t
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cam_iosched_now(void)
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{
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/* Cast here is to avoid right shifting a signed value */
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return (uintptr_t)((uint64_t)sbinuptime() >> CAM_IOSCHED_TIME_SHIFT);
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}
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static inline uintptr_t
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cam_iosched_delta_t(uintptr_t then)
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{
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/* Since the types are identical, wrapping works correctly */
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return (cam_iosched_now() - then);
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}
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static inline sbintime_t
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cam_iosched_sbintime_t(uintptr_t delta)
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{
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/* Cast here is to widen the type so the left shift doesn't lose precision */
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return (sbintime_t)((uint64_t)delta << CAM_IOSCHED_TIME_SHIFT);
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}
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int cam_iosched_init(struct cam_iosched_softc **, struct cam_periph *periph);
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void cam_iosched_fini(struct cam_iosched_softc *);
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void cam_iosched_sysctl_init(struct cam_iosched_softc *, struct sysctl_ctx_list *, struct sysctl_oid *);
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struct bio *cam_iosched_next_trim(struct cam_iosched_softc *isc);
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struct bio *cam_iosched_get_trim(struct cam_iosched_softc *isc);
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struct bio *cam_iosched_next_bio(struct cam_iosched_softc *isc);
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void cam_iosched_queue_work(struct cam_iosched_softc *isc, struct bio *bp);
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void cam_iosched_flush(struct cam_iosched_softc *isc, struct devstat *stp, int err);
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void cam_iosched_schedule(struct cam_iosched_softc *isc, struct cam_periph *periph);
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void cam_iosched_finish_trim(struct cam_iosched_softc *isc);
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void cam_iosched_submit_trim(struct cam_iosched_softc *isc);
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void cam_iosched_put_back_trim(struct cam_iosched_softc *isc, struct bio *bp);
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void cam_iosched_set_sort_queue(struct cam_iosched_softc *isc, int val);
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int cam_iosched_has_work_flags(struct cam_iosched_softc *isc, uint32_t flags);
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void cam_iosched_set_work_flags(struct cam_iosched_softc *isc, uint32_t flags);
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void cam_iosched_clr_work_flags(struct cam_iosched_softc *isc, uint32_t flags);
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void cam_iosched_trim_done(struct cam_iosched_softc *isc);
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int cam_iosched_bio_complete(struct cam_iosched_softc *isc, struct bio *bp, union ccb *done_ccb);
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#endif
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#endif
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