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Gather sample queue and lock into a static cacheline-aligned struct.

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This commit is contained in:
riastradh 2015-04-08 02:49:03 +00:00
parent 6f2d8f443b
commit 12d3f8e076
1 changed files with 21 additions and 21 deletions
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42
sys/kern/kern_rndq.c
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@ -1,4 +1,4 @@
/* $NetBSD: kern_rndq.c,v 1.33 2015/04/08 02:44:07 riastradh Exp $ */
/* $NetBSD: kern_rndq.c,v 1.34 2015/04/08 02:49:03 riastradh Exp $ */
/*-
* Copyright (c) 1997-2013 The NetBSD Foundation, Inc.
@ -32,7 +32,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.33 2015/04/08 02:44:07 riastradh Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.34 2015/04/08 02:49:03 riastradh Exp $");
#include <sys/param.h>
#include <sys/atomic.h>
@ -109,11 +109,13 @@ typedef struct _rnd_sample_t {
} rnd_sample_t;
/*
* The event queue. Fields are altered at an interrupt level.
* All accesses must be protected with the mutex.
* The sample queue. Samples are put into the queue and processed in a
* softint in order to limit the latency of adding a sample.
*/
SIMPLEQ_HEAD(, _rnd_sample_t) rnd_samples;
kmutex_t rnd_mtx;
static struct {
kmutex_t lock;
SIMPLEQ_HEAD(, _rnd_sample_t) q;
} rnd_samples __cacheline_aligned;
/*
* Memory pool for sample buffers
@ -522,7 +524,7 @@ rnd_init(void)
if (rnd_ready)
return;
mutex_init(&rnd_mtx, MUTEX_DEFAULT, IPL_VM);
mutex_init(&rnd_samples.lock, MUTEX_DEFAULT, IPL_VM);
rndsinks_init();
/*
@ -532,7 +534,7 @@ rnd_init(void)
c = rnd_counter();
LIST_INIT(&rnd_sources);
SIMPLEQ_INIT(&rnd_samples);
SIMPLEQ_INIT(&rnd_samples.q);
rndpool_init(&rnd_pool);
mutex_init(&rndpool_mtx, MUTEX_DEFAULT, IPL_VM);
@ -738,15 +740,15 @@ rnd_detach_source(krndsource_t *source)
* If there are samples queued up "remove" them from the sample queue
* by setting the source to the no-collect pseudosource.
*/
mutex_spin_enter(&rnd_mtx);
sample = SIMPLEQ_FIRST(&rnd_samples);
mutex_spin_enter(&rnd_samples.lock);
sample = SIMPLEQ_FIRST(&rnd_samples.q);
while (sample != NULL) {
if (sample->source == source)
sample->source = &rnd_source_no_collect;
sample = SIMPLEQ_NEXT(sample, next);
}
mutex_spin_exit(&rnd_mtx);
mutex_spin_exit(&rnd_samples.lock);
if (!cpu_softintr_p()) { /* XXX XXX very temporary "fix" */
if (source->state) {
@ -955,12 +957,12 @@ rnd_add_data_ts(krndsource_t *rs, const void *const data, u_int32_t len,
return;
}
mutex_spin_enter(&rnd_mtx);
mutex_spin_enter(&rnd_samples.lock);
while ((state = SIMPLEQ_FIRST(&tmp_samples))) {
SIMPLEQ_REMOVE_HEAD(&tmp_samples, next);
SIMPLEQ_INSERT_HEAD(&rnd_samples, state, next);
SIMPLEQ_INSERT_HEAD(&rnd_samples.q, state, next);
}
mutex_spin_exit(&rnd_mtx);
mutex_spin_exit(&rnd_samples.lock);
/* Cause processing of queued samples */
rnd_schedule_process();
@ -1040,14 +1042,12 @@ rnd_process_events(void)
SIMPLEQ_HEAD_INITIALIZER(df_samples);
/*
* Sample queue is protected by rnd_mtx, drain to onstack queue
* and drop lock.
* Drain to the on-stack queue and drop the lock.
*/
mutex_spin_enter(&rnd_mtx);
while ((sample = SIMPLEQ_FIRST(&rnd_samples))) {
mutex_spin_enter(&rnd_samples.lock);
while ((sample = SIMPLEQ_FIRST(&rnd_samples.q))) {
found++;
SIMPLEQ_REMOVE_HEAD(&rnd_samples, next);
SIMPLEQ_REMOVE_HEAD(&rnd_samples.q, next);
/*
* We repeat this check here, since it is possible
* the source was disabled before we were called, but
@ -1061,7 +1061,7 @@ rnd_process_events(void)
SIMPLEQ_INSERT_TAIL(&dq_samples, sample, next);
}
}
mutex_spin_exit(&rnd_mtx);
mutex_spin_exit(&rnd_samples.lock);
/* Don't thrash the rndpool mtx either. Hold, add all samples. */
mutex_spin_enter(&rndpool_mtx);