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Use only one single condvar(9) for devices and events, they are protected 

by the same mutex (sme_mtx) and there's no point in using two of them.

Also add a comment mentioning some locking notes.

Reviewed and ok by rmind.
This commit is contained in:
xtraeme 2007-09-08 15:25:18 +00:00
parent 5e02e37306
commit 70a37300e4
3 changed files with 34 additions and 24 deletions
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34
sys/dev/sysmon/sysmon_envsys.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: sysmon_envsys.c,v 1.60 2007/09/08 03:41:28 xtraeme Exp $ */
/* $NetBSD: sysmon_envsys.c,v 1.61 2007/09/08 15:25:18 xtraeme Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
@ -75,7 +75,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sysmon_envsys.c,v 1.60 2007/09/08 03:41:28 xtraeme Exp $");
__KERNEL_RCSID(0, "$NetBSD: sysmon_envsys.c,v 1.61 2007/09/08 15:25:18 xtraeme Exp $");
#include <sys/param.h>
#include <sys/types.h>
@ -93,12 +93,27 @@ __KERNEL_RCSID(0, "$NetBSD: sysmon_envsys.c,v 1.60 2007/09/08 03:41:28 xtraeme E
#include <dev/sysmon/sysmon_envsysvar.h>
#include <dev/sysmon/sysmon_taskq.h>
static prop_dictionary_t sme_propd;
static kcondvar_t sme_list_cv;
/*
* Notes about locking:
*
* There's a global lock 'sme_mtx' to protect access to 'sysmon_envsys_list'
* (devices linked list), 'struct sysmon_envsys' (device), 'sme_events_list'
* (events linked list), 'sme_event_t' (event) and the global counter
* 'sysmon_envsys_next_sensor_index'.
*
* Another lock 'sme_init_mtx' is used to protect initialization and
* finalization of the events framework (the callout(9) and workqueue(9)
* that is used to check for conditions and sending events to powerd(8)).
*
* The global 'sme_cv' condition variable is used to wait for state changes
* on the 'sysmon_envsys_list' and 'sme_events_list' linked lists.
*
*/
kmutex_t sme_mtx, sme_event_init_mtx;
kcondvar_t sme_event_cv;
kcondvar_t sme_cv;
static prop_dictionary_t sme_propd;
static uint32_t sysmon_envsys_next_sensor_index = 0;
static struct sysmon_envsys *sysmon_envsys_find_40(u_int);
@ -118,8 +133,7 @@ sysmon_envsys_init(void)
LIST_INIT(&sme_events_list);
mutex_init(&sme_mtx, MUTEX_DRIVER, IPL_NONE);
mutex_init(&sme_event_init_mtx, MUTEX_DRIVER, IPL_NONE);
cv_init(&sme_list_cv, "smefind");
cv_init(&sme_event_cv, "smeevent");
cv_init(&sme_cv, "smework");
sme_propd = prop_dictionary_create();
}
@ -577,7 +591,7 @@ sysmon_envsys_unregister(struct sysmon_envsys *sme)
mutex_enter(&sme_mtx);
while (sme->sme_flags & SME_FLAG_BUSY) {
sme->sme_flags |= SME_FLAG_WANTED;
cv_wait(&sme_list_cv, &sme_mtx);
cv_wait(&sme_cv, &sme_mtx);
}
sysmon_envsys_next_sensor_index -= sme->sme_nsensors;
/*
@ -621,7 +635,7 @@ again:
if (strcmp(sme->sme_name, name) == 0) {
if (sme->sme_flags & SME_FLAG_BUSY) {
sme->sme_flags |= SME_FLAG_WANTED;
cv_wait(&sme_list_cv, &sme_mtx);
cv_wait(&sme_cv, &sme_mtx);
goto again;
}
sme->sme_flags |= SME_FLAG_BUSY;
@ -642,7 +656,7 @@ sysmon_envsys_release(struct sysmon_envsys *sme)
{
mutex_enter(&sme_mtx);
if (sme->sme_flags & SME_FLAG_WANTED)
cv_broadcast(&sme_list_cv);
cv_broadcast(&sme_cv);
sme->sme_flags &= ~(SME_FLAG_BUSY | SME_FLAG_WANTED);
mutex_exit(&sme_mtx);
}

12
sys/dev/sysmon/sysmon_envsys_events.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: sysmon_envsys_events.c,v 1.32 2007/09/08 03:41:28 xtraeme Exp $ */
/* $NetBSD: sysmon_envsys_events.c,v 1.33 2007/09/08 15:25:18 xtraeme Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
@ -41,7 +41,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sysmon_envsys_events.c,v 1.32 2007/09/08 03:41:28 xtraeme Exp $");
__KERNEL_RCSID(0, "$NetBSD: sysmon_envsys_events.c,v 1.33 2007/09/08 15:25:18 xtraeme Exp $");
#include <sys/param.h>
#include <sys/types.h>
@ -78,7 +78,7 @@ static struct workqueue *seewq;
static struct callout seeco;
static bool sme_events_initialized = false;
kmutex_t sme_mtx, sme_event_init_mtx;
kcondvar_t sme_event_cv;
kcondvar_t sme_cv;
/* 10 seconds of timeout for the callout */
static int sme_events_timeout = 10;
@ -275,7 +275,7 @@ sme_event_unregister_all(const char *sme_name)
see->pes.pes_sensname, see->type, sme_name));
while (see->see_flags & SME_EVENT_WORKING)
cv_wait(&sme_event_cv, &sme_mtx);
cv_wait(&sme_cv, &sme_mtx);
LIST_REMOVE(see, see_list);
kmem_free(see, sizeof(*see));
@ -320,7 +320,7 @@ sme_event_unregister(const char *sensor, int type)
}
while (see->see_flags & SME_EVENT_WORKING)
cv_wait(&sme_event_cv, &sme_mtx);
cv_wait(&sme_cv, &sme_mtx);
DPRINTF(("%s: removing dev=%s sensor=%s type=%d\n",
__func__, see->pes.pes_dvname, sensor, type));
@ -632,6 +632,6 @@ do { \
}
out:
see->see_flags &= ~SME_EVENT_WORKING;
cv_broadcast(&sme_event_cv);
cv_broadcast(&sme_cv);
mutex_exit(&sme_mtx);
}

12
sys/dev/sysmon/sysmon_envsysvar.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: sysmon_envsysvar.h,v 1.18 2007/09/08 03:17:38 xtraeme Exp $ */
/* $NetBSD: sysmon_envsysvar.h,v 1.19 2007/09/08 15:25:19 xtraeme Exp $ */
/*-
* Copyright (c) 2007 The NetBSD Foundation, Inc.
@ -105,13 +105,9 @@ struct sme_description_table {
};
/* common */
extern kmutex_t sme_mtx; /* mutex for the sysmon envsys devices/events */
/* mutex to intialize/destroy the sysmon envsys events framework */
extern kmutex_t sme_event_init_mtx;
/* condition variable to wait for the worker thread to finish */
extern kcondvar_t sme_event_cv;
extern kmutex_t sme_mtx; /* mutex for devices/events */
extern kmutex_t sme_event_init_mtx; /* init/destroy the events framework */
extern kcondvar_t sme_cv; /* to wait for devices/events working */
/* linked list for the sysmon envsys devices */
LIST_HEAD(, sysmon_envsys) sysmon_envsys_list;