Add locking to handle multiple threads getting/setting frequencies at the
same time. We use an sx lock and serialize the cpufreq device's get/set/levels methods.
This commit is contained in:
Nate Lawson
parent
5f4aa96715
commit
789f03ceb4
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=142603
@ -32,6 +32,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/cpu.h>
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#include <sys/eventhandler.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/module.h>
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#include <sys/proc.h>
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@ -40,6 +41,7 @@ __FBSDID("$FreeBSD$");
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#include <sys/sbuf.h>
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#include <sys/sx.h>
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#include <sys/timetc.h>
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#include "cpufreq_if.h"
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@ -56,6 +58,7 @@ __FBSDID("$FreeBSD$");
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#define CF_MAX_LEVELS 64
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struct cpufreq_softc {
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struct sx lock;
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struct cf_level curr_level;
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int curr_priority;
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struct cf_level saved_level;
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@ -75,6 +78,11 @@ struct cf_setting_array {
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TAILQ_HEAD(cf_setting_lst, cf_setting_array);
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#define CF_MTX_INIT(x) sx_init((x), "cpufreq lock")
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#define CF_MTX_LOCK(x) sx_xlock((x))
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#define CF_MTX_UNLOCK(x) sx_xunlock((x))
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#define CF_MTX_ASSERT(x) sx_assert((x), SX_XLOCKED)
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static int cpufreq_attach(device_t dev);
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static int cpufreq_detach(device_t dev);
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static void cpufreq_evaluate(void *arg);
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@ -129,6 +137,7 @@ cpufreq_attach(device_t dev)
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sc->dev = dev;
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sysctl_ctx_init(&sc->sysctl_ctx);
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TAILQ_INIT(&sc->all_levels);
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CF_MTX_INIT(&sc->lock);
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sc->curr_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
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sc->saved_level.total_set.freq = CPUFREQ_VAL_UNKNOWN;
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sc->max_mhz = CPUFREQ_VAL_UNKNOWN;
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@ -188,6 +197,8 @@ cf_set_method(device_t dev, const struct cf_level *level, int priority)
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int cpu_id, error, i;
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sc = device_get_softc(dev);
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error = 0;
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set = NULL;
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/*
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* Check that the TSC isn't being used as a timecounter.
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@ -203,22 +214,29 @@ cf_set_method(device_t dev, const struct cf_level *level, int priority)
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* If they did specify one, but the requested level has a lower
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* priority, don't allow the new level right now.
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*/
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CF_MTX_LOCK(&sc->lock);
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if (level == NULL) {
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if (sc->saved_level.total_set.freq != CPUFREQ_VAL_UNKNOWN) {
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level = &sc->saved_level;
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priority = sc->saved_priority;
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} else
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return (ENXIO);
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} else if (priority < sc->curr_priority)
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return (EPERM);
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} else {
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error = ENXIO;
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goto out;
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}
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} else if (priority < sc->curr_priority) {
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error = EPERM;
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goto out;
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}
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/* Reject levels that are below our specified threshold. */
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if (level->total_set.freq <= cf_lowest_freq)
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return (EINVAL);
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if (level->total_set.freq <= cf_lowest_freq) {
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error = EINVAL;
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goto out;
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}
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/* If already at this level, just return. */
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if (CPUFREQ_CMP(sc->curr_level.total_set.freq, level->total_set.freq))
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return (0);
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goto out;
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/* First, set the absolute frequency via its driver. */
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set = &level->abs_set;
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@ -297,7 +315,8 @@ cf_set_method(device_t dev, const struct cf_level *level, int priority)
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error = 0;
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out:
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if (error)
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CF_MTX_UNLOCK(&sc->lock);
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if (error && set)
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device_printf(set->dev, "set freq failed, err %d\n", error);
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return (error);
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}
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@ -314,12 +333,15 @@ cf_get_method(device_t dev, struct cf_level *level)
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uint64_t rate;
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sc = device_get_softc(dev);
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curr_set = &sc->curr_level.total_set;
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error = 0;
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levels = NULL;
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/* If we already know the current frequency, we're done. */
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CF_MTX_LOCK(&sc->lock);
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curr_set = &sc->curr_level.total_set;
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if (curr_set->freq != CPUFREQ_VAL_UNKNOWN)
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goto out;
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CF_MTX_UNLOCK(&sc->lock);
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/*
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* We need to figure out the current level. Loop through every
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@ -334,11 +356,24 @@ cf_get_method(device_t dev, struct cf_level *level)
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if (error) {
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if (error == E2BIG)
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printf("cpufreq: need to increase CF_MAX_LEVELS\n");
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goto out;
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free(levels, M_TEMP);
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return (error);
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}
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error = device_get_children(device_get_parent(dev), &devs, &numdevs);
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if (error)
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goto out;
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if (error) {
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free(levels, M_TEMP);
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return (error);
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}
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/*
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* Reacquire the lock and search for the given level.
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*
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* XXX Note: this is not quite right since we really need to go
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* through each level and compare both absolute and relative
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* settings for each driver in the system before making a match.
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* The estimation code below catches this case though.
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*/
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CF_MTX_LOCK(&sc->lock);
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for (i = 0; i < numdevs && curr_set->freq == CPUFREQ_VAL_UNKNOWN; i++) {
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if (!device_is_attached(devs[i]))
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continue;
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@ -375,10 +410,13 @@ cf_get_method(device_t dev, struct cf_level *level)
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}
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out:
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if (error == 0)
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*level = sc->curr_level;
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CF_MTX_UNLOCK(&sc->lock);
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if (levels)
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free(levels, M_TEMP);
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*level = sc->curr_level;
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return (0);
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return (error);
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}
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static int
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@ -409,6 +447,7 @@ cf_levels_method(device_t dev, struct cf_level *levels, int *count)
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}
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/* Get settings from all cpufreq drivers. */
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CF_MTX_LOCK(&sc->lock);
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for (i = 0; i < numdevs; i++) {
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/* Skip devices that aren't ready. */
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if (!device_is_attached(devs[i]))
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@ -502,11 +541,13 @@ cf_levels_method(device_t dev, struct cf_level *levels, int *count)
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TAILQ_REMOVE(&sc->all_levels, lev, link);
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free(lev, M_TEMP);
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}
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sc->all_count = 0;
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CF_MTX_UNLOCK(&sc->lock);
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while ((set_arr = TAILQ_FIRST(&rel_sets)) != NULL) {
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TAILQ_REMOVE(&rel_sets, set_arr, link);
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free(set_arr, M_TEMP);
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}
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sc->all_count = 0;
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free(devs, M_TEMP);
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free(sets, M_TEMP);
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return (error);
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@ -524,6 +565,8 @@ cpufreq_insert_abs(struct cpufreq_softc *sc, struct cf_setting *sets,
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struct cf_level *level, *search;
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int i;
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CF_MTX_ASSERT(&sc->lock);
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list = &sc->all_levels;
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for (i = 0; i < count; i++) {
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level = malloc(sizeof(*level), M_TEMP, M_NOWAIT | M_ZERO);
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@ -559,6 +602,8 @@ cpufreq_expand_set(struct cpufreq_softc *sc, struct cf_setting_array *set_arr)
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struct cf_setting *set;
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int i;
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CF_MTX_ASSERT(&sc->lock);
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TAILQ_FOREACH(search, &sc->all_levels, link) {
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/* Skip this level if we've already modified it. */
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for (i = 0; i < search->rel_count; i++) {
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@ -608,6 +653,8 @@ cpufreq_dup_set(struct cpufreq_softc *sc, struct cf_level *dup,
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struct cf_setting *fill_set, *itr_set;
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int i;
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CF_MTX_ASSERT(&sc->lock);
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/*
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* Create a new level, copy it from the old one, and update the
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* total frequency and power by the percentage specified in the
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