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https://github.com/torvalds/linux
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2abe542087
Originally, bcachefs - going back to bcache - stored, for each bucket, a 16 bit counter corresponding to how long it had been since the bucket was read from. But, this required periodically rescaling counters on every bucket to avoid wraparound. That wasn't an issue in bcache, where we'd perodically rewrite the per bucket metadata all at once, but in bcachefs we're trying to avoid having to walk every single bucket. This patch switches to persisting 64 bit io clocks, corresponding to the 64 bit bucket timestaps introduced in the previous patch with KEY_TYPE_alloc_v2. Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
38 lines
724 B
C
38 lines
724 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _BCACHEFS_CLOCK_TYPES_H
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#define _BCACHEFS_CLOCK_TYPES_H
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#include "util.h"
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#define NR_IO_TIMERS (BCH_SB_MEMBERS_MAX * 3)
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/*
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* Clocks/timers in units of sectors of IO:
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*
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* Note - they use percpu batching, so they're only approximate.
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*/
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struct io_timer;
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typedef void (*io_timer_fn)(struct io_timer *);
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struct io_timer {
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io_timer_fn fn;
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unsigned long expire;
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};
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/* Amount to buffer up on a percpu counter */
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#define IO_CLOCK_PCPU_SECTORS 128
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typedef HEAP(struct io_timer *) io_timer_heap;
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struct io_clock {
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atomic64_t now;
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u16 __percpu *pcpu_buf;
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unsigned max_slop;
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spinlock_t timer_lock;
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io_timer_heap timers;
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};
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#endif /* _BCACHEFS_CLOCK_TYPES_H */
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