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sh: intc: optimize intc IRQ lookup

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This ensures that the sense/prio lists are sorted at registration time,
enabling us to use a simple binary search for an optimized lookup
(something that had been on the TODO for some time).

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2012-01-24 17:41:55 +09:00
parent 3037764213
commit b59f9f9775
3 changed files with 22 additions and 22 deletions
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27
drivers/sh/intc/chip.c
View File

@ -2,13 +2,14 @@
* IRQ chip definitions for INTC IRQs.
*
* Copyright (C) 2007, 2008 Magnus Damm
* Copyright (C) 2009, 2010 Paul Mundt
* Copyright (C) 2009 - 2012 Paul Mundt
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/cpumask.h>
#include <linux/bsearch.h>
#include <linux/io.h>
#include "internals.h"
@ -117,28 +118,12 @@ static struct intc_handle_int *intc_find_irq(struct intc_handle_int *hp,
unsigned int nr_hp,
unsigned int irq)
{
int i;
struct intc_handle_int key;
/*
* this doesn't scale well, but...
*
* this function should only be used for cerain uncommon
* operations such as intc_set_priority() and intc_set_type()
* and in those rare cases performance doesn't matter that much.
* keeping the memory footprint low is more important.
*
* one rather simple way to speed this up and still keep the
* memory footprint down is to make sure the array is sorted
* and then perform a bisect to lookup the irq.
*/
for (i = 0; i < nr_hp; i++) {
if ((hp + i)->irq != irq)
continue;
key.irq = irq;
key.handle = 0;
return hp + i;
}
return NULL;
return bsearch(&key, hp, nr_hp, sizeof(*hp), intc_handle_int_cmp);
}
int intc_set_priority(unsigned int irq, unsigned int prio)

9
drivers/sh/intc/core.c
View File

@ -2,7 +2,7 @@
* Shared interrupt handling code for IPR and INTC2 types of IRQs.
*
* Copyright (C) 2007, 2008 Magnus Damm
* Copyright (C) 2009, 2010 Paul Mundt
* Copyright (C) 2009 - 2012 Paul Mundt
*
* Based on intc2.c and ipr.c
*
@ -31,6 +31,7 @@
#include <linux/spinlock.h>
#include <linux/radix-tree.h>
#include <linux/export.h>
#include <linux/sort.h>
#include "internals.h"
LIST_HEAD(intc_list);
@ -267,6 +268,9 @@ int __init register_intc_controller(struct intc_desc *desc)
k += save_reg(d, k, hw->prio_regs[i].set_reg, smp);
k += save_reg(d, k, hw->prio_regs[i].clr_reg, smp);
}
sort(d->prio, hw->nr_prio_regs, sizeof(*d->prio),
intc_handle_int_cmp, NULL);
}
if (hw->sense_regs) {
@ -277,6 +281,9 @@ int __init register_intc_controller(struct intc_desc *desc)
for (i = 0; i < hw->nr_sense_regs; i++)
k += save_reg(d, k, hw->sense_regs[i].reg, 0);
sort(d->sense, hw->nr_sense_regs, sizeof(*d->sense),
intc_handle_int_cmp, NULL);
}
if (hw->subgroups)

8
drivers/sh/intc/internals.h
View File

@ -108,6 +108,14 @@ static inline void activate_irq(int irq)
#endif
}
static inline int intc_handle_int_cmp(const void *a, const void *b)
{
const struct intc_handle_int *_a = a;
const struct intc_handle_int *_b = b;
return _a->irq - _b->irq;
}
/* access.c */
extern unsigned long
(*intc_reg_fns[])(unsigned long addr, unsigned long h, unsigned long data);