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[PATCH] shrink mmtimer memory size 

This greatly reduces the amount of memory used by mmtimer on smaller
machines with large values of MAX_COMPACT_NODES.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Dimitri Sivanich 2006-01-06 11:33:41 -06:00 committed by Linus Torvalds
parent c0e7dcc8bc
commit 76832c28de
1 changed files with 57 additions and 33 deletions
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90
drivers/char/mmtimer.c
View File

@ -1,11 +1,11 @@
/*
* Intel Multimedia Timer device implementation for SGI SN platforms.
* Timer device implementation for SGI SN platforms.
*
* 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.
*
* Copyright (c) 2001-2004 Silicon Graphics, Inc. All rights reserved.
* Copyright (c) 2001-2006 Silicon Graphics, Inc. All rights reserved.
*
* This driver exports an API that should be supportable by any HPET or IA-PC
* multimedia timer. The code below is currently specific to the SGI Altix
@ -45,7 +45,7 @@ MODULE_LICENSE("GPL");
/* name of the device, usually in /dev */
#define MMTIMER_NAME "mmtimer"
#define MMTIMER_DESC "SGI Altix RTC Timer"
#define MMTIMER_VERSION "2.0"
#define MMTIMER_VERSION "2.1"
#define RTC_BITS 55 /* 55 bits for this implementation */
@ -227,10 +227,7 @@ typedef struct mmtimer {
struct tasklet_struct tasklet;
} mmtimer_t;
/*
* Total number of comparators is comparators/node * MAX nodes/running kernel
*/
static mmtimer_t timers[NUM_COMPARATORS*MAX_COMPACT_NODES];
static mmtimer_t ** timers;
/**
* mmtimer_ioctl - ioctl interface for /dev/mmtimer
@ -441,29 +438,29 @@ static irqreturn_t
mmtimer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
int i;
mmtimer_t *base = timers + cpu_to_node(smp_processor_id()) *
NUM_COMPARATORS;
unsigned long expires = 0;
int result = IRQ_NONE;
unsigned indx = cpu_to_node(smp_processor_id());
/*
* Do this once for each comparison register
*/
for (i = 0; i < NUM_COMPARATORS; i++) {
mmtimer_t *base = timers[indx] + i;
/* Make sure this doesn't get reused before tasklet_sched */
spin_lock(&base[i].lock);
if (base[i].cpu == smp_processor_id()) {
if (base[i].timer)
expires = base[i].timer->it.mmtimer.expires;
spin_lock(&base->lock);
if (base->cpu == smp_processor_id()) {
if (base->timer)
expires = base->timer->it.mmtimer.expires;
/* expires test won't work with shared irqs */
if ((mmtimer_int_pending(i) > 0) ||
(expires && (expires < rtc_time()))) {
mmtimer_clr_int_pending(i);
tasklet_schedule(&base[i].tasklet);
tasklet_schedule(&base->tasklet);
result = IRQ_HANDLED;
}
}
spin_unlock(&base[i].lock);
spin_unlock(&base->lock);
expires = 0;
}
return result;
@ -523,7 +520,7 @@ static int sgi_timer_del(struct k_itimer *timr)
{
int i = timr->it.mmtimer.clock;
cnodeid_t nodeid = timr->it.mmtimer.node;
mmtimer_t *t = timers + nodeid * NUM_COMPARATORS +i;
mmtimer_t *t = timers[nodeid] + i;
unsigned long irqflags;
if (i != TIMER_OFF) {
@ -609,11 +606,11 @@ static int sgi_timer_set(struct k_itimer *timr, int flags,
preempt_disable();
nodeid = cpu_to_node(smp_processor_id());
base = timers + nodeid * NUM_COMPARATORS;
retry:
/* Don't use an allocated timer, or a deleted one that's pending */
for(i = 0; i< NUM_COMPARATORS; i++) {
if (!base[i].timer && !base[i].tasklet.state) {
base = timers[nodeid] + i;
if (!base->timer && !base->tasklet.state) {
break;
}
}
@ -623,14 +620,14 @@ retry:
return -EBUSY;
}
spin_lock_irqsave(&base[i].lock, irqflags);
spin_lock_irqsave(&base->lock, irqflags);
if (base[i].timer || base[i].tasklet.state != 0) {
spin_unlock_irqrestore(&base[i].lock, irqflags);
if (base->timer || base->tasklet.state != 0) {
spin_unlock_irqrestore(&base->lock, irqflags);
goto retry;
}
base[i].timer = timr;
base[i].cpu = smp_processor_id();
base->timer = timr;
base->cpu = smp_processor_id();
timr->it.mmtimer.clock = i;
timr->it.mmtimer.node = nodeid;
@ -645,11 +642,11 @@ retry:
}
} else {
timr->it.mmtimer.expires -= period;
if (reschedule_periodic_timer(base+i))
if (reschedule_periodic_timer(base))
err = -EINVAL;
}
spin_unlock_irqrestore(&base[i].lock, irqflags);
spin_unlock_irqrestore(&base->lock, irqflags);
preempt_enable();
@ -675,6 +672,7 @@ static struct k_clock sgi_clock = {
static int __init mmtimer_init(void)
{
unsigned i;
cnodeid_t node, maxn = -1;
if (!ia64_platform_is("sn2"))
return -1;
@ -691,14 +689,6 @@ static int __init mmtimer_init(void)
mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
2) / sn_rtc_cycles_per_second;
for (i=0; i< NUM_COMPARATORS*MAX_COMPACT_NODES; i++) {
spin_lock_init(&timers[i].lock);
timers[i].timer = NULL;
timers[i].cpu = 0;
timers[i].i = i % NUM_COMPARATORS;
tasklet_init(&timers[i].tasklet, mmtimer_tasklet, (unsigned long) (timers+i));
}
if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, SA_PERCPU_IRQ, MMTIMER_NAME, NULL)) {
printk(KERN_WARNING "%s: unable to allocate interrupt.",
MMTIMER_NAME);
@ -712,6 +702,40 @@ static int __init mmtimer_init(void)
return -1;
}
/* Get max numbered node, calculate slots needed */
for_each_online_node(node) {
maxn = node;
}
maxn++;
/* Allocate list of node ptrs to mmtimer_t's */
timers = kmalloc(sizeof(mmtimer_t *)*maxn, GFP_KERNEL);
if (timers == NULL) {
printk(KERN_ERR "%s: failed to allocate memory for device\n",
MMTIMER_NAME);
return -1;
}
/* Allocate mmtimer_t's for each online node */
for_each_online_node(node) {
timers[node] = kmalloc_node(sizeof(mmtimer_t)*NUM_COMPARATORS, GFP_KERNEL, node);
if (timers[node] == NULL) {
printk(KERN_ERR "%s: failed to allocate memory for device\n",
MMTIMER_NAME);
return -1;
}
for (i=0; i< NUM_COMPARATORS; i++) {
mmtimer_t * base = timers[node] + i;
spin_lock_init(&base->lock);
base->timer = NULL;
base->cpu = 0;
base->i = i;
tasklet_init(&base->tasklet, mmtimer_tasklet,
(unsigned long) (base));
}
}
sgi_clock_period = sgi_clock.res = NSEC_PER_SEC / sn_rtc_cycles_per_second;
register_posix_clock(CLOCK_SGI_CYCLE, &sgi_clock);