common/os/pg.c

	pg.c revision 0e7515250c8395f368aa45fb9acae7c4f8f8b786
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/systm.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/thread.h>
#include <sys/cpuvar.h>
#include <sys/cpupart.h>
#include <sys/kmem.h>
#include <sys/cmn_err.h>
#include <sys/kstat.h>
#include <sys/processor.h>
#include <sys/disp.h>
#include <sys/group.h>
#include <sys/pg.h>

/*
 * Processor groups
 *
 * With the introduction of Chip Multi-Threaded (CMT) processor architectures,
 * it is no longer necessarily true that a given physical processor module
 * will present itself as a single schedulable entity (cpu_t). Rather, each
 * chip and/or processor core may present itself as one or more "logical" CPUs.
 *
 * The logical CPUs presented may share physical components such as caches,
 * data pipes, execution pipelines, FPUs, etc. It is advantageous to have the
 * kernel be aware of the relationships existing between logical CPUs so that
 * the appropriate optmizations may be employed.
 *
 * The processor group abstraction represents a set of logical CPUs that
 * generally share some sort of physical or characteristic relationship.
 *
 * In the case of a physical sharing relationship, the CPUs in the group may
 * share a pipeline, cache or floating point unit. In the case of a logical
 * relationship, a PG may represent the set of CPUs in a processor set, or the
 * set of CPUs running at a particular clock speed.
 *
 * The generic processor group structure, pg_t, contains the elements generic
 * to a group of CPUs. Depending on the nature of the CPU relationship
 * (LOGICAL or PHYSICAL), a pointer to a pg may be recast to a "view" of that
 * PG where more specific data is represented.
 *
 * As an example, a PG representing a PHYSICAL relationship, may be recast to
 * a pghw_t, where data further describing the hardware sharing relationship
 * is maintained. See pghw.c and pghw.h for details on physical PGs.
 *
 * At this time a more specialized casting of a PG representing a LOGICAL
 * relationship has not been implemented, but the architecture allows for this
 * in the future.
 *
 * Processor Group Classes
 *
 * Processor group consumers may wish to maintain and associate specific
 * data with the PGs they create. For this reason, a mechanism for creating
 * class specific PGs exists. Classes may overload the default functions for
 * creating, destroying, and associating CPUs with PGs, and may also register
 * class specific callbacks to be invoked when the CPU related system
 * configuration changes. Class specific data is stored/associated with
 * PGs by incorporating the pg_t (or pghw_t, as appropriate), as the first
 * element of a class specific PG object. In memory, such a structure may look
 * like:
 *
 * ----------------------- - - -
 * | common              | | | |  <--(pg_t *)
 * ----------------------- | | -
 * | HW specific         | | | <-----(pghw_t *)
 * ----------------------- | -
 * | class specific      | | <-------(pg_cmt_t *)
 * ----------------------- -
 *
 * Access to the PG class specific data can be had by casting a pointer to
 * it's class specific view.
 */

static pg_t     *pg_alloc_default(pg_class_t);
static void     pg_free_default(pg_t *);
static void     pg_null_op();

/*
 * Bootstrap CPU specific PG data
 * See pg_cpu_bootstrap()
 */
static cpu_pg_t     bootstrap_pg_data;

/*
 * Bitset of allocated PG ids (they are sequential)
 * and the next free id in the set.
 */
static bitset_t     pg_id_set;
static pgid_t       pg_id_next = 0;

/*
 * Default and externed PG ops vectors
 */
static struct pg_ops pg_ops_default = {
    pg_alloc_default,   /* alloc */
    pg_free_default,    /* free */
    NULL,           /* cpu_init */
    NULL,           /* cpu_fini */
    NULL,           /* cpu_active */
    NULL,           /* cpu_inactive */
    NULL,           /* cpupart_in */
    NULL,           /* cpupart_out */
    NULL,           /* cpupart_move */
    NULL,           /* cpu_belongs */
    NULL,           /* policy_name */
};

static struct pg_cb_ops pg_cb_ops_default = {
    pg_null_op,     /* thread_swtch */
    pg_null_op,     /* thread_remain */
};

/*
 * Class specific PG allocation callbacks
 */
#define PG_ALLOC(class)                         \
    (pg_classes[class].pgc_ops->alloc ?             \
        pg_classes[class].pgc_ops->alloc() :            \
        pg_classes[pg_default_cid].pgc_ops->alloc())

#define PG_FREE(pg)                         \
    ((pg)->pg_class->pgc_ops->free ?                \
        (pg)->pg_class->pgc_ops->free(pg) :             \
        pg_classes[pg_default_cid].pgc_ops->free(pg))       \


/*
 * Class specific PG policy name
 */
#define PG_POLICY_NAME(pg)                      \
    ((pg)->pg_class->pgc_ops->policy_name ?             \
        (pg)->pg_class->pgc_ops->policy_name(pg) : NULL)        \

/*
 * Class specific membership test callback
 */
#define PG_CPU_BELONGS(pg, cp)                      \
    ((pg)->pg_class->pgc_ops->cpu_belongs ?             \
        (pg)->pg_class->pgc_ops->cpu_belongs(pg, cp) : 0)       \

/*
 * CPU configuration callbacks
 */
#define PG_CPU_INIT(class, cp)                      \
{                                   \
    if (pg_classes[class].pgc_ops->cpu_init)            \
        pg_classes[class].pgc_ops->cpu_init(cp);        \
}

#define PG_CPU_FINI(class, cp)                      \
{                                   \
    if (pg_classes[class].pgc_ops->cpu_fini)            \
        pg_classes[class].pgc_ops->cpu_fini(cp);        \
}

#define PG_CPU_ACTIVE(class, cp)                    \
{                                   \
    if (pg_classes[class].pgc_ops->cpu_active)          \
        pg_classes[class].pgc_ops->cpu_active(cp);      \
}

#define PG_CPU_INACTIVE(class, cp)                  \
{                                   \
    if (pg_classes[class].pgc_ops->cpu_inactive)            \
        pg_classes[class].pgc_ops->cpu_inactive(cp);        \
}

/*
 * CPU / cpupart configuration callbacks
 */
#define PG_CPUPART_IN(class, cp, pp)                    \
{                                   \
    if (pg_classes[class].pgc_ops->cpupart_in)          \
        pg_classes[class].pgc_ops->cpupart_in(cp, pp);      \
}

#define PG_CPUPART_OUT(class, cp, pp)                   \
{                                   \
    if (pg_classes[class].pgc_ops->cpupart_out)         \
        pg_classes[class].pgc_ops->cpupart_out(cp, pp);     \
}

#define PG_CPUPART_MOVE(class, cp, old, new)                \
{                                   \
    if (pg_classes[class].pgc_ops->cpupart_move)            \
        pg_classes[class].pgc_ops->cpupart_move(cp, old, new);  \
}


static pg_class_t   *pg_classes;
static int      pg_nclasses;

static pg_cid_t     pg_default_cid;

/*
 * Initialze common PG subsystem.
 */
void
pg_init(void)
{
    extern void pg_cmt_class_init();

    pg_default_cid =
        pg_class_register("default", &pg_ops_default, PGR_LOGICAL);

    /*
     * Initialize classes to allow them to register with the framework
     */
    pg_cmt_class_init();

    pg_cpu0_init();
}

/*
 * Perform CPU 0 initialization
 */
void
pg_cpu0_init(void)
{
    extern void pghw_physid_create();

    /*
     * Create the physical ID cache for the boot CPU
     */
    pghw_physid_create(CPU);

    /*
     * pg_cpu_* require that cpu_lock be held
     */
    mutex_enter(&cpu_lock);

    pg_cpu_init(CPU);
    pg_cpupart_in(CPU, &cp_default);
    pg_cpu_active(CPU);

    mutex_exit(&cpu_lock);
}

/*
 * Invoked when topology for CPU0 changes
 * post pg_cpu0_init().
 *
 * Currently happens as a result of null_proc_lpa
 * on Starcat.
 */
void
pg_cpu0_reinit(void)
{
    mutex_enter(&cpu_lock);
    pg_cpu_inactive(CPU);
    pg_cpupart_out(CPU, &cp_default);
    pg_cpu_fini(CPU);

    pg_cpu_init(CPU);
    pg_cpupart_in(CPU, &cp_default);
    pg_cpu_active(CPU);
    mutex_exit(&cpu_lock);
}

/*
 * Register a new PG class
 */
pg_cid_t
pg_class_register(char *name, struct pg_ops *ops, pg_relation_t relation)
{
    pg_class_t  *newclass;
    pg_class_t  *classes_old;
    id_t        cid;

    mutex_enter(&cpu_lock);

    /*
     * Allocate a new pg_class_t in the pg_classes array
     */
    if (pg_nclasses == 0) {
        pg_classes = kmem_zalloc(sizeof (pg_class_t), KM_SLEEP);
    } else {
        classes_old = pg_classes;
        pg_classes =
            kmem_zalloc(sizeof (pg_class_t) * (pg_nclasses + 1),
            KM_SLEEP);
        (void) kcopy(classes_old, pg_classes,
            sizeof (pg_class_t) * pg_nclasses);
        kmem_free(classes_old, sizeof (pg_class_t) * pg_nclasses);
    }

    cid = pg_nclasses++;
    newclass = &pg_classes[cid];

    (void) strncpy(newclass->pgc_name, name, PG_CLASS_NAME_MAX);
    newclass->pgc_id = cid;
    newclass->pgc_ops = ops;
    newclass->pgc_relation = relation;

    mutex_exit(&cpu_lock);

    return (cid);
}

/*
 * Try to find an existing pg in set in which to place cp.
 * Returns the pg if found, and NULL otherwise.
 * In the event that the CPU could belong to multiple
 * PGs in the set, the first matching PG will be returned.
 */
pg_t *
pg_cpu_find_pg(cpu_t *cp, group_t *set)
{
    pg_t        *pg;
    group_iter_t    i;

    group_iter_init(&i);
    while ((pg = group_iterate(set, &i)) != NULL) {
        /*
         * Ask the class if the CPU belongs here
         */
        if (PG_CPU_BELONGS(pg, cp))
            return (pg);
    }
    return (NULL);
}

/*
 * Iterate over the CPUs in a PG after initializing
 * the iterator with PG_CPU_ITR_INIT()
 */
cpu_t *
pg_cpu_next(pg_cpu_itr_t *itr)
{
    cpu_t       *cpu;
    pg_t        *pg = itr->pg;

    cpu = group_iterate(&pg->pg_cpus, &itr->position);
    return (cpu);
}

/*
 * Test if a given PG contains a given CPU
 */
boolean_t
pg_cpu_find(pg_t *pg, cpu_t *cp)
{
    if (group_find(&pg->pg_cpus, cp) == (uint_t)-1)
        return (B_FALSE);

    return (B_TRUE);
}

/*
 * Set the PGs callbacks to the default
 */
void
pg_callback_set_defaults(pg_t *pg)
{
    bcopy(&pg_cb_ops_default, &pg->pg_cb, sizeof (struct pg_cb_ops));
}

/*
 * Create a PG of a given class.
 * This routine may block.
 */
pg_t *
pg_create(pg_cid_t cid)
{
    pg_t    *pg;
    pgid_t  id;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /*
     * Call the class specific PG allocation routine
     */
    pg = PG_ALLOC(cid);
    pg->pg_class = &pg_classes[cid];
    pg->pg_relation = pg->pg_class->pgc_relation;

    /*
     * Find the next free sequential pg id
     */
    do {
        if (pg_id_next >= bitset_capacity(&pg_id_set))
            bitset_resize(&pg_id_set, pg_id_next + 1);
        id = pg_id_next++;
    } while (bitset_in_set(&pg_id_set, id));

    pg->pg_id = id;
    bitset_add(&pg_id_set, pg->pg_id);

    /*
     * Create the PG's CPU group
     */
    group_create(&pg->pg_cpus);

    /*
     * Initialize the events ops vector
     */
    pg_callback_set_defaults(pg);

    return (pg);
}

/*
 * Destroy a PG.
 * This routine may block.
 */
void
pg_destroy(pg_t *pg)
{
    ASSERT(MUTEX_HELD(&cpu_lock));

    group_destroy(&pg->pg_cpus);

    /*
     * Unassign the pg_id
     */
    if (pg_id_next > pg->pg_id)
        pg_id_next = pg->pg_id;
    bitset_del(&pg_id_set, pg->pg_id);

    /*
     * Invoke the class specific de-allocation routine
     */
    PG_FREE(pg);
}

/*
 * Add the CPU "cp" to processor group "pg"
 * This routine may block.
 */
void
pg_cpu_add(pg_t *pg, cpu_t *cp)
{
    int err;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /* This adds the CPU to the PG's CPU group */
    err = group_add(&pg->pg_cpus, cp, GRP_RESIZE);
    ASSERT(err == 0);

    /* This adds the PG to the CPUs PG group */
    ASSERT(cp->cpu_pg != &bootstrap_pg_data);
    err = group_add(&cp->cpu_pg->pgs, pg, GRP_RESIZE);
    ASSERT(err == 0);
}

/*
 * Remove "cp" from "pg".
 * This routine may block.
 */
void
pg_cpu_delete(pg_t *pg, cpu_t *cp)
{
    int err;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /* Remove the CPU from the PG */
    err = group_remove(&pg->pg_cpus, cp, GRP_RESIZE);
    ASSERT(err == 0);

    /* Remove the PG from the CPU's PG group */
    ASSERT(cp->cpu_pg != &bootstrap_pg_data);
    err = group_remove(&cp->cpu_pg->pgs, pg, GRP_RESIZE);
    ASSERT(err == 0);
}

/*
 * Allocate a CPU's PG data. This hangs off struct cpu at cpu_pg
 */
static cpu_pg_t *
pg_cpu_data_alloc(void)
{
    cpu_pg_t    *pgd;

    pgd = kmem_zalloc(sizeof (cpu_pg_t), KM_SLEEP);
    group_create(&pgd->pgs);
    group_create(&pgd->cmt_pgs);

    return (pgd);
}

/*
 * Free the CPU's PG data.
 */
static void
pg_cpu_data_free(cpu_pg_t *pgd)
{
    group_destroy(&pgd->pgs);
    group_destroy(&pgd->cmt_pgs);
    kmem_free(pgd, sizeof (cpu_pg_t));
}

/*
 * A new CPU is coming into the system, either via booting or DR.
 * Allocate it's PG data, and notify all registered classes about
 * the new CPU.
 *
 * This routine may block.
 */
void
pg_cpu_init(cpu_t *cp)
{
    pg_cid_t    i;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /*
     * Allocate and size the per CPU pg data
     */
    cp->cpu_pg = pg_cpu_data_alloc();

    /*
     * Notify all registered classes about the new CPU
     */
    for (i = 0; i < pg_nclasses; i++)
        PG_CPU_INIT(i, cp);
}

/*
 * This CPU is being deleted from the system. Notify the classes
 * and free up the CPU's PG data.
 */
void
pg_cpu_fini(cpu_t *cp)
{
    pg_cid_t    i;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /*
     * This can happen if the CPU coming into the system
     * failed to power on.
     */
    if (cp->cpu_pg == NULL ||
        cp->cpu_pg == &bootstrap_pg_data)
        return;

    for (i = 0; i < pg_nclasses; i++)
        PG_CPU_FINI(i, cp);

    pg_cpu_data_free(cp->cpu_pg);
    cp->cpu_pg = NULL;
}

/*
 * This CPU is becoming active (online)
 * This routine may not block as it is called from paused CPUs
 * context.
 */
void
pg_cpu_active(cpu_t *cp)
{
    pg_cid_t    i;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /*
     * Notify all registered classes about the new CPU
     */
    for (i = 0; i < pg_nclasses; i++)
        PG_CPU_ACTIVE(i, cp);
}

/*
 * This CPU is going inactive (offline)
 * This routine may not block, as it is called from paused
 * CPUs context.
 */
void
pg_cpu_inactive(cpu_t *cp)
{
    pg_cid_t    i;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /*
     * Notify all registered classes about the new CPU
     */
    for (i = 0; i < pg_nclasses; i++)
        PG_CPU_INACTIVE(i, cp);
}

/*
 * Invoked when the CPU is about to move into the partition
 * This routine may block.
 */
void
pg_cpupart_in(cpu_t *cp, cpupart_t *pp)
{
    int i;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /*
     * Notify all registered classes that the
     * CPU is about to enter the CPU partition
     */
    for (i = 0; i < pg_nclasses; i++)
        PG_CPUPART_IN(i, cp, pp);
}

/*
 * Invoked when the CPU is about to move out of the partition
 * This routine may block.
 */
/*ARGSUSED*/
void
pg_cpupart_out(cpu_t *cp, cpupart_t *pp)
{
    int i;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /*
     * Notify all registered classes that the
     * CPU is about to leave the CPU partition
     */
    for (i = 0; i < pg_nclasses; i++)
        PG_CPUPART_OUT(i, cp, pp);
}

/*
 * Invoked when the CPU is *moving* partitions.
 *
 * This routine may not block, as it is called from paused CPUs
 * context.
 */
void
pg_cpupart_move(cpu_t *cp, cpupart_t *oldpp, cpupart_t *newpp)
{
    int i;

    ASSERT(MUTEX_HELD(&cpu_lock));

    /*
     * Notify all registered classes that the
     * CPU is about to leave the CPU partition
     */
    for (i = 0; i < pg_nclasses; i++)
        PG_CPUPART_MOVE(i, cp, oldpp, newpp);
}

/*
 * Return a class specific string describing a policy implemented
 * across this PG
 */
char *
pg_policy_name(pg_t *pg)
{
    char *str;
    if ((str = PG_POLICY_NAME(pg)) != NULL)
        return (str);

    return ("N/A");
}

/*
 * Provide the specified CPU a bootstrap pg
 * This is needed to allow sane behaviour if any PG consuming
 * code needs to deal with a partially initialized CPU
 */
void
pg_cpu_bootstrap(cpu_t *cp)
{
    cp->cpu_pg = &bootstrap_pg_data;
}

/*ARGSUSED*/
static pg_t *
pg_alloc_default(pg_class_t class)
{
    return (kmem_zalloc(sizeof (pg_t), KM_SLEEP));
}

/*ARGSUSED*/
static void
pg_free_default(struct pg *pg)
{
    kmem_free(pg, sizeof (pg_t));
}

static void
pg_null_op()
{
}

/*
 * Invoke the "thread switch" callback for each of the CPU's PGs
 * This is invoked from the dispatcher swtch() routine, which is called
 * when a thread running an a CPU should switch to another thread.
 * "cp" is the CPU on which the thread switch is happening
 * "now" is an unscaled hrtime_t timestamp taken in swtch()
 * "old" and "new" are the outgoing and incoming threads, respectively.
 */
void
pg_ev_thread_swtch(struct cpu *cp, hrtime_t now, kthread_t *old, kthread_t *new)
{
    int i, sz;
    group_t *grp;
    pg_t    *pg;

    grp = &cp->cpu_pg->pgs;
    sz = GROUP_SIZE(grp);
    for (i = 0; i < sz; i++) {
        pg = GROUP_ACCESS(grp, i);
        pg->pg_cb.thread_swtch(pg, cp, now, old, new);
    }
}

/*
 * Invoke the "thread remain" callback for each of the CPU's PGs.
 * This is called from the dispatcher's swtch() routine when a thread
 * running on the CPU "cp" is switching to itself, which can happen as an
 * artifact of the thread's timeslice expiring.
 */
void
pg_ev_thread_remain(struct cpu *cp, kthread_t *t)
{
    int i, sz;
    group_t *grp;
    pg_t    *pg;

    grp = &cp->cpu_pg->pgs;
    sz = GROUP_SIZE(grp);
    for (i = 0; i < sz; i++) {
        pg = GROUP_ACCESS(grp, i);
        pg->pg_cb.thread_remain(pg, cp, t);
    }
}