f1a1ad338d
Drastically reduces the amount of time spent rewriting parity after an unclean shutdown by keeping better track of which regions might have had outstanding writes. Enabled by default; can be disabled on a per-set basis, or tuned, with the new raidctl(8) commands. Discussed on tech-kern@ to a general air of approval; exhortations to commit from mrg@, christos@, and others. Thanks to Google for their sponsorship, oster@ for mentoring the project, assorted developers for trying very hard to break it, and probably more I'm forgetting.
126 lines
4.2 KiB
C
126 lines
4.2 KiB
C
/* $NetBSD: rf_paritymap.h,v 1.1 2009/11/17 18:54:26 jld Exp $ */
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/*-
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* Copyright (c) 2009 Jed Davis.
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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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/mutex.h>
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#include <sys/param.h>
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#include <sys/rwlock.h>
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#include <sys/types.h>
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#include <dev/raidframe/raidframevar.h>
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/* RF_PARITYMAP_N* in raidframevar.h */
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#define RF_PMLABEL_VALID 1
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#define RF_PMLABEL_WASUSED 2
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#define RF_PMLABEL_DISABLE 4
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/*
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* On-disk format: a single bit for each region; if the bit is clear,
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* then the parity is clean.
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*/
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struct rf_paritymap_ondisk
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{
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/* XXX Do these really need to be volatile? */
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volatile char bits[RF_PARITYMAP_NBYTE];
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};
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/* In-core per-region state: a byte for each, encoded as follows. */
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struct rf_paritymap_current
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{
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volatile int8_t state[RF_PARITYMAP_NREG];
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/*
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* Values:
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* if x == 0, the region may be written out as clean
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* if x > 0, then x outstanding IOs to that region
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* if x < 0, then there was recently IO; periodically increment x
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*/
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};
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/* The entire state. */
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struct rf_paritymap
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{
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struct rf_paritymap_ondisk *disk_boot, *disk_now;
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struct rf_paritymap_current *current;
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/*
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* This lock will be held while component disks' caches are
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* flushed, which could take many milliseconds, so it should
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* not be taken where that kind of delay is unacceptable.
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* Contention on this lock is not, however, expected to be a
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* performance bottleneck.
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*/
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kmutex_t lock;
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/*
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* The flags field, below, has its own lock so that
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* inter-thread communication can occur without taking the
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* overall lock. Ordering is lock -> lk_flags.
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*/
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kmutex_t lk_flags;
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RF_Raid_t *raid;
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daddr_t region_size;
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callout_t ticker;
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struct rf_pmparams params;
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volatile int flags;
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struct rf_pmctrs ctrs;
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};
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void rf_paritymap_status(struct rf_paritymap *, struct rf_pmstat *);
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int rf_paritymap_test(struct rf_paritymap *, daddr_t);
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void rf_paritymap_begin_region(struct rf_paritymap *, unsigned);
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void rf_paritymap_begin(struct rf_paritymap *, daddr_t, daddr_t);
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void rf_paritymap_end_region(struct rf_paritymap *, unsigned);
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void rf_paritymap_end(struct rf_paritymap *, daddr_t, daddr_t);
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void rf_paritymap_checkwork(struct rf_paritymap *);
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void rf_paritymap_invalidate(struct rf_paritymap *);
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void rf_paritymap_forceclean(struct rf_paritymap *);
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void rf_paritymap_write(struct rf_paritymap *);
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int rf_paritymap_init(struct rf_paritymap *, RF_Raid_t *,
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const struct rf_pmparams *);
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void rf_paritymap_destroy(struct rf_paritymap *, int);
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int rf_paritymap_rewrite(struct rf_paritymap *);
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int rf_paritymap_merge(struct rf_paritymap_ondisk *,
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struct rf_paritymap_ondisk *);
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void rf_paritymap_attach(RF_Raid_t *, int);
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void rf_paritymap_detach(RF_Raid_t *); /* Not while the RAID is live! */
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int rf_paritymap_get_disable(RF_Raid_t *);
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void rf_paritymap_set_disable(RF_Raid_t *, int);
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int rf_paritymap_set_params(struct rf_paritymap *,
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const struct rf_pmparams *, int);
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void rf_paritymap_init_label(struct rf_paritymap *,
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RF_ComponentLabel_t *);
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