incubator-nuttx/sched/group/group_join.c

237 lines
7.1 KiB
C

/****************************************************************************
* sched/group/group_join.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/kmalloc.h>
#include "sched/sched.h"
#include "group/group.h"
#include "environ/environ.h"
#ifndef CONFIG_DISABLE_PTHREAD
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Is this worth making a configuration option? */
#define GROUP_REALLOC_MEMBERS 4
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: group_addmember
*
* Description:
* Add a new member to a group.
*
* Input Parameters:
* group - The task group to add the new member
* pid - The new member
*
* Returned Value:
* 0 (OK) on success; a negated errno value on failure.
*
* Assumptions:
* Called during thread creation and during reparenting in a safe context.
* No special precautions are required here.
*
****************************************************************************/
#ifdef HAVE_GROUP_MEMBERS
static inline int group_addmember(FAR struct task_group_s *group, pid_t pid)
{
FAR pid_t *oldmembers = NULL;
irqstate_t flags;
DEBUGASSERT(group && group->tg_nmembers < UINT8_MAX);
/* Will we need to extend the size of the array of groups? */
if (group->tg_nmembers >= group->tg_mxmembers)
{
FAR pid_t *newmembers;
unsigned int newmax;
/* Yes... reallocate the array of members */
newmax = group->tg_mxmembers + GROUP_REALLOC_MEMBERS;
if (newmax > UINT8_MAX)
{
newmax = UINT8_MAX;
}
newmembers = kmm_malloc(sizeof(pid_t) * newmax);
if (!newmembers)
{
serr("ERROR: Failed to reallocate tg_members\n");
return -ENOMEM;
}
/* Save the new number of members in the reallocated members array.
* We need to make the following atomic because the member list
* may be traversed from an interrupt handler (read-only).
*/
flags = spin_lock_irqsave(NULL);
memcpy(newmembers, group->tg_members,
sizeof(pid_t) * group->tg_mxmembers);
oldmembers = group->tg_members;
group->tg_members = newmembers;
group->tg_mxmembers = newmax;
}
else
{
flags = spin_lock_irqsave(NULL);
}
/* Assign this new pid to the group; group->tg_nmembers will be incremented
* by the caller.
*/
group->tg_members[group->tg_nmembers] = pid;
group->tg_nmembers++;
spin_unlock_irqrestore(NULL, flags);
if (oldmembers != NULL)
{
kmm_free(oldmembers);
}
return OK;
}
#endif /* HAVE_GROUP_MEMBERS */
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: group_bind
*
* Description:
* A thread joins the group when it is created. This is a two step process,
* first, the group must bound to the new threads TCB. group_bind() does
* this (at the return from group_join, things are a little unstable: The
* group has been bound, but tg_nmembers has not yet been incremented).
* Then, after the new thread is initialized and has a PID assigned to it,
* group_join() is called, incrementing the tg_nmembers count on the group.
*
* Input Parameters:
* tcb - The TCB of the new "child" task that need to join the group.
*
* Returned Value:
* 0 (OK) on success; a negated errno value on failure.
*
* Assumptions:
* - The parent task from which the group will be inherited is the task at
* the head of the ready to run list.
* - Called during thread creation in a safe context. No special precautions
* are required here.
*
****************************************************************************/
int group_bind(FAR struct pthread_tcb_s *tcb)
{
FAR struct tcb_s *ptcb = this_task();
DEBUGASSERT(ptcb && tcb && ptcb->group && !tcb->cmn.group);
/* Copy the group reference from the parent to the child */
tcb->cmn.group = ptcb->group;
return OK;
}
/****************************************************************************
* Name: group_join
*
* Description:
* A thread joins the group when it is created. This is a two step process,
* first, the group must bound to the new threads TCB. group_bind() does
* this (at the return from group_join, things are a little unstable: The
* group has been bound, but tg_nmembers has not yet been incremented).
* Then, after the new thread is initialized and has a PID assigned to it,
* group_join() is called, incrementing the tg_nmembers count on the group.
*
* Input Parameters:
* tcb - The TCB of the new "child" task that need to join the group.
*
* Returned Value:
* 0 (OK) on success; a negated errno value on failure.
*
* Assumptions:
* - The parent task from which the group will be inherited is the task at
* the head of the ready to run list.
* - Called during thread creation in a safe context. No special precautions
* are required here.
*
****************************************************************************/
int group_join(FAR struct pthread_tcb_s *tcb)
{
FAR struct task_group_s *group;
#ifdef HAVE_GROUP_MEMBERS
int ret;
#else
irqstate_t flags;
#endif
DEBUGASSERT(tcb && tcb->cmn.group &&
tcb->cmn.group->tg_nmembers < UINT8_MAX);
/* Get the group from the TCB */
group = tcb->cmn.group;
#ifdef HAVE_GROUP_MEMBERS
/* Add the member to the group */
ret = group_addmember(group, tcb->cmn.pid);
if (ret < 0)
{
return ret;
}
#else
flags = spin_lock_irqsave(NULL);
group->tg_nmembers++;
spin_unlock_irqrestore(NULL, flags);
#endif
return OK;
}
#endif /* !CONFIG_DISABLE_PTHREAD */