Commit be5f1797 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

flex_proportions: Allow N events instead of 1 



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: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
parent bd3488e7

include/linux/flex_proportions.h

+5 −4
Original line number Diff line number Diff line
@@ -83,9 +83,10 @@ struct fprop_local_percpu { 


int fprop_local_init_percpu(struct fprop_local_percpu *pl, gfp_t gfp);

void fprop_local_destroy_percpu(struct fprop_local_percpu *pl);

void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl);

void __fprop_inc_percpu_max(struct fprop_global *p, struct fprop_local_percpu *pl,

			    int max_frac);

void __fprop_add_percpu(struct fprop_global *p, struct fprop_local_percpu *pl,

		long nr);

void __fprop_add_percpu_max(struct fprop_global *p,

		struct fprop_local_percpu *pl, int max_frac, long nr);

void fprop_fraction_percpu(struct fprop_global *p,

	struct fprop_local_percpu *pl, unsigned long *numerator,

	unsigned long *denominator);
@@ -96,7 +97,7 @@ void fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl) 
	unsigned long flags;



	local_irq_save(flags);

	__fprop_inc_percpu(p, pl);

	__fprop_add_percpu(p, pl, 1);

	local_irq_restore(flags);

}

lib/flex_proportions.c

+19 −9
Original line number Diff line number Diff line
@@ -217,11 +217,12 @@ static void fprop_reflect_period_percpu(struct fprop_global *p, 
}



/* Event of type pl happened */

void __fprop_inc_percpu(struct fprop_global *p, struct fprop_local_percpu *pl)

void __fprop_add_percpu(struct fprop_global *p, struct fprop_local_percpu *pl,

		long nr)

{

	fprop_reflect_period_percpu(p, pl);

	percpu_counter_add_batch(&pl->events, 1, PROP_BATCH);

	percpu_counter_add(&p->events, 1);

	percpu_counter_add_batch(&pl->events, nr, PROP_BATCH);

	percpu_counter_add(&p->events, nr);

}



void fprop_fraction_percpu(struct fprop_global *p,
@@ -253,20 +254,29 @@ void fprop_fraction_percpu(struct fprop_global *p, 
}



/*

 * Like __fprop_inc_percpu() except that event is counted only if the given

 * Like __fprop_add_percpu() except that event is counted only if the given

 * type has fraction smaller than @max_frac/FPROP_FRAC_BASE

 */

void __fprop_inc_percpu_max(struct fprop_global *p,

			    struct fprop_local_percpu *pl, int max_frac)

void __fprop_add_percpu_max(struct fprop_global *p,

		struct fprop_local_percpu *pl, int max_frac, long nr)

{

	if (unlikely(max_frac < FPROP_FRAC_BASE)) {

		unsigned long numerator, denominator;

		s64 tmp;



		fprop_fraction_percpu(p, pl, &numerator, &denominator);

		if (numerator >

		    (((u64)denominator) * max_frac) >> FPROP_FRAC_SHIFT)

		/* Adding 'nr' to fraction exceeds max_frac/FPROP_FRAC_BASE? */

		tmp = (u64)denominator * max_frac -

					((u64)numerator << FPROP_FRAC_SHIFT);

		if (tmp < 0) {

			/* Maximum fraction already exceeded? */

			return;

		} else if (tmp < nr * (FPROP_FRAC_BASE - max_frac)) {

			/* Add just enough for the fraction to saturate */

			nr = div_u64(tmp + FPROP_FRAC_BASE - max_frac - 1,

					FPROP_FRAC_BASE - max_frac);

		}

	}



	__fprop_inc_percpu(p, pl);

	__fprop_add_percpu(p, pl, nr);

}

mm/page-writeback.c

+2 −2
Original line number Diff line number Diff line
@@ -566,8 +566,8 @@ static void wb_domain_writeout_inc(struct wb_domain *dom, 
				   struct fprop_local_percpu *completions,

				   unsigned int max_prop_frac)

{

	__fprop_inc_percpu_max(&dom->completions, completions,

			       max_prop_frac);

	__fprop_add_percpu_max(&dom->completions, completions,

			       max_prop_frac, 1);

	/* First event after period switching was turned off? */

	if (unlikely(!dom->period_time)) {

		/*