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be5f179752
When batching events (such as writing back N pages in a single I/O), it is better to do one flex_proportion operation instead of N. There is only one caller of __fprop_inc_percpu_max(), and it's the one we're going to change in the next patch, so rename it instead of adding a compatibility wrapper. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz>
104 lines
2.8 KiB
C
104 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Floating proportions with flexible aging period
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*
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* Copyright (C) 2011, SUSE, Jan Kara <jack@suse.cz>
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*/
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#ifndef _LINUX_FLEX_PROPORTIONS_H
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#define _LINUX_FLEX_PROPORTIONS_H
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#include <linux/percpu_counter.h>
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#include <linux/spinlock.h>
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#include <linux/seqlock.h>
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#include <linux/gfp.h>
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/*
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* When maximum proportion of some event type is specified, this is the
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* precision with which we allow limitting. Note that this creates an upper
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* bound on the number of events per period like
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* ULLONG_MAX >> FPROP_FRAC_SHIFT.
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*/
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#define FPROP_FRAC_SHIFT 10
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#define FPROP_FRAC_BASE (1UL << FPROP_FRAC_SHIFT)
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/*
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* ---- Global proportion definitions ----
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*/
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struct fprop_global {
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/* Number of events in the current period */
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struct percpu_counter events;
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/* Current period */
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unsigned int period;
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/* Synchronization with period transitions */
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seqcount_t sequence;
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};
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int fprop_global_init(struct fprop_global *p, gfp_t gfp);
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void fprop_global_destroy(struct fprop_global *p);
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bool fprop_new_period(struct fprop_global *p, int periods);
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/*
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* ---- SINGLE ----
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*/
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struct fprop_local_single {
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/* the local events counter */
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unsigned long events;
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/* Period in which we last updated events */
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unsigned int period;
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raw_spinlock_t lock; /* Protect period and numerator */
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};
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#define INIT_FPROP_LOCAL_SINGLE(name) \
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{ .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
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}
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int fprop_local_init_single(struct fprop_local_single *pl);
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void fprop_local_destroy_single(struct fprop_local_single *pl);
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void __fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl);
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void fprop_fraction_single(struct fprop_global *p,
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struct fprop_local_single *pl, unsigned long *numerator,
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unsigned long *denominator);
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static inline
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void fprop_inc_single(struct fprop_global *p, struct fprop_local_single *pl)
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{
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unsigned long flags;
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local_irq_save(flags);
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__fprop_inc_single(p, pl);
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local_irq_restore(flags);
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}
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/*
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* ---- PERCPU ----
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*/
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struct fprop_local_percpu {
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/* the local events counter */
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struct percpu_counter events;
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/* Period in which we last updated events */
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unsigned int period;
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raw_spinlock_t lock; /* Protect period and numerator */
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};
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int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp);
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void fprop_local_destroy_percpu(struct fprop_local_percpu *pl);
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void __fprop_add_percpu(struct fprop_global *p, struct fprop_local_percpu *pl,
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long nr);
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void __fprop_add_percpu_max(struct fprop_global *p,
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struct fprop_local_percpu *pl, int max_frac, long nr);
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void fprop_fraction_percpu(struct fprop_global *p,
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struct fprop_local_percpu *pl, unsigned long *numerator,
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unsigned long *denominator);
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static inline
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void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl)
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{
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unsigned long flags;
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local_irq_save(flags);
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__fprop_add_percpu(p, pl, 1);
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local_irq_restore(flags);
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}
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#endif
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