mm/iob: Add an IOB notifier that will send a signal to any registered threads that want to be notified when an IOB has been freed. This is an untested work-in-progress and is intended to be a part of a larger solution to correctly handling network poll operations.
This commit is contained in:
Gregory Nutt
parent
ddaea5dabc
commit
bba8541ad6
|
|
@ -204,6 +204,63 @@ int iob_navail(void);
|
|||
|
||||
FAR struct iob_s *iob_free(FAR struct iob_s *iob);
|
||||
|
||||
/****************************************************************************
|
||||
* Name: iob_notify_setup
|
||||
*
|
||||
* Description:
|
||||
* Set up to notify the specified PID with the provided signal number.
|
||||
*
|
||||
* NOTE: To avoid race conditions, the caller should set the sigprocmask
|
||||
* to block signal delivery. The signal will be delivered once the
|
||||
* signal is removed from the sigprocmask.
|
||||
*
|
||||
* Input Parameters:
|
||||
* pid - The PID to be notified. If a zero value is provided, then the
|
||||
* PID of the calling thread will be used.
|
||||
* signo - The signal number to use with the notification.
|
||||
*
|
||||
* Returned Value:
|
||||
* > 0 - There are already free IOBs and this this number of free IOBs
|
||||
* (CAUTION: This value is volatile). No signal notification
|
||||
* will be provided.
|
||||
* == 0 - There are no free IOBs. A signal will be sent to 'pid' when
|
||||
* at least one IOB is available. That IOB is *not* reserved for
|
||||
* the caller. Hence, due to race conditions, it could be taken
|
||||
* by some other task. In that event, the caller should call
|
||||
* sig_notify again.
|
||||
* < 0 - An unexpected error occurred and no signal will be sent. The
|
||||
* returned value is a negated errno value that indicates the
|
||||
* nature of the failure.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
#ifdef CONFIG_IOB_NOTIFIER
|
||||
int iob_notify_setup(int pid, int signo);
|
||||
#endif
|
||||
|
||||
/****************************************************************************
|
||||
* Name: iob_notify_teardown
|
||||
*
|
||||
* Description:
|
||||
* Eliminate an IOB notification previously setup by iob_notify_setup().
|
||||
* This function should only be called if the notification should be
|
||||
* aborted prior to the notification. The notification will automatically
|
||||
* be torn down after the signal is sent.
|
||||
*
|
||||
* Input Parameters:
|
||||
* pid - The PID whose notification will be torn down. If a zero value
|
||||
* is provided, then the PID of the calling thread will be used.
|
||||
*
|
||||
* Returned Value:
|
||||
* Zero (OK) is returned on success; a negated errno value is returned on
|
||||
* any failure.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
#ifdef CONFIG_IOB_NOTIFIER
|
||||
int iob_notify_teardown(int pid, int signo);
|
||||
#endif
|
||||
|
||||
/****************************************************************************
|
||||
* Name: iob_free_chain
|
||||
*
|
||||
|
|
|
|||
|
|
@ -59,6 +59,26 @@ config IOB_THROTTLE
|
|||
I/O buffers will be denied to the read-ahead logic before TCP writes
|
||||
are halted.
|
||||
|
||||
config IOB_NOTIFIER
|
||||
bool "Support IOB notifications"
|
||||
default n
|
||||
---help---
|
||||
Enable building of IOB notifier logic that will send a signla to
|
||||
a kernel thread when an IOB is available. This is is a general
|
||||
purpose notifier, but was developed specifically to support poll()
|
||||
logic where the poll must wait for an IOB to become available.
|
||||
|
||||
config IOB_NWAITERS
|
||||
int "Number of IOB waiters"
|
||||
default 4
|
||||
range 1 32767
|
||||
depends on IOB_NOTIFIER
|
||||
---help---
|
||||
If CONFIG_IOB_NOTIFIER is selected, then a static array will be
|
||||
allocated to hold information about pending notifications. This
|
||||
then determines an upper limit for the number of waiters that can
|
||||
be supported.
|
||||
|
||||
config IOB_DEBUG
|
||||
bool "Force I/O buffer debug"
|
||||
default n
|
||||
|
|
|
|||
|
|
@ -44,6 +44,10 @@ CSRCS += iob_initialize.c iob_pack.c iob_peek_queue.c iob_remove_queue.c
|
|||
CSRCS += iob_trimhead.c iob_trimhead_queue.c iob_trimtail.c
|
||||
CSRCS += iob_navail.c
|
||||
|
||||
ifeq ($(CONFIG_IOB_NOTIFIER),y)
|
||||
CSRCS += iob_notify.c
|
||||
endif
|
||||
|
||||
ifeq ($(CONFIG_DEBUG_FEATURES),y)
|
||||
CSRCS += iob_dump.c
|
||||
endif
|
||||
|
|
|
|||
24
mm/iob/iob.h
24
mm/iob/iob.h
|
|
@ -154,6 +154,30 @@ FAR struct iob_qentry_s *iob_tryalloc_qentry(void);
|
|||
|
||||
FAR struct iob_qentry_s *iob_free_qentry(FAR struct iob_qentry_s *iobq);
|
||||
|
||||
/****************************************************************************
|
||||
* Name: iob_notify_signal
|
||||
*
|
||||
* Description:
|
||||
* An IOB has become available. Signal all threads waiting for an IOB
|
||||
* that an IOB is available.
|
||||
*
|
||||
* When an IOB becomes available, *all* of the waiters in this thread will
|
||||
* be signaled. If there are multiple waiters then only the highest
|
||||
* priority thread will get the IOB. Lower priority threads will need to
|
||||
* call iob_notify once again.
|
||||
*
|
||||
* Input Parameters:
|
||||
* None.
|
||||
*
|
||||
* Returned Value:
|
||||
* None.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
#ifdef CONFIG_IOB_NOTIFIER
|
||||
void iob_notify_signal(void);
|
||||
#endif
|
||||
|
||||
#endif /* CONFIG_MM_IOB */
|
||||
#endif /* __MM_IOB_IOB_H */
|
||||
|
||||
|
|
|
|||
|
|
@ -1,7 +1,7 @@
|
|||
/****************************************************************************
|
||||
* mm/iob/iob_free.c
|
||||
*
|
||||
* Copyright (C) 2014, 2016-2017 Gregory Nutt. All rights reserved.
|
||||
* Copyright (C) 2014, 2016-2018 Gregory Nutt. All rights reserved.
|
||||
* Author: Gregory Nutt <gnutt@nuttx.org>
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
|
|
@ -126,16 +126,32 @@ FAR struct iob_s *iob_free(FAR struct iob_s *iob)
|
|||
g_iob_freelist = iob;
|
||||
}
|
||||
|
||||
/* Signal that an IOB is available. If there is a thread waiting
|
||||
* for an IOB, this will wake up exactly one thread. The semaphore
|
||||
* count will correctly indicated that the awakened task owns an
|
||||
* IOB and should find it in the committed list.
|
||||
/* Signal that an IOB is available. If there is a thread blocked,
|
||||
* waiting for an IOB, this will wake up exactly one thread. The
|
||||
* semaphore count will correctly indicated that the awakened task
|
||||
* owns an IOB and should find it in the committed list.
|
||||
*/
|
||||
|
||||
nxsem_post(&g_iob_sem);
|
||||
#if CONFIG_IOB_THROTTLE > 0
|
||||
nxsem_post(&g_throttle_sem);
|
||||
#endif
|
||||
|
||||
#ifdef CONFIG_IOB_NOTIFIER
|
||||
/* Check if the IOB was claimed by a thread that is blocked waiting
|
||||
* for an IOB.
|
||||
*/
|
||||
|
||||
if (iob_navail() > 0)
|
||||
{
|
||||
/* Signal any threads that have requested a signal notification
|
||||
* when an IOB becomes available.
|
||||
*/
|
||||
|
||||
iob_notify_signal();
|
||||
}
|
||||
#endif
|
||||
|
||||
leave_critical_section(flags);
|
||||
|
||||
/* And return the I/O buffer after the one that was freed */
|
||||
|
|
|
|||
|
|
@ -0,0 +1,288 @@
|
|||
/****************************************************************************
|
||||
* mm/iob/iob_notify.c
|
||||
*
|
||||
* Copyright (C) 2018 Gregory Nutt. All rights reserved.
|
||||
* Author: Gregory Nutt <gnutt@nuttx.org>
|
||||
*
|
||||
* Redistribution and use in source and binary forms, with or without
|
||||
* modification, are permitted provided that the following conditions
|
||||
* are met:
|
||||
*
|
||||
* 1. Redistributions of source code must retain the above copyright
|
||||
* notice, this list of conditions and the following disclaimer.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in
|
||||
* the documentation and/or other materials provided with the
|
||||
* distribution.
|
||||
* 3. Neither the name NuttX nor the names of its contributors may be
|
||||
* used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
||||
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
||||
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
||||
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
||||
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
||||
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
||||
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
||||
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
||||
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
||||
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||||
* POSSIBILITY OF SUCH DAMAGE.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
/****************************************************************************
|
||||
* Included Files
|
||||
****************************************************************************/
|
||||
|
||||
#include <nuttx/config.h>
|
||||
|
||||
#include <sys/types.h>
|
||||
#include <stdint.h>
|
||||
#include <stdbool.h>
|
||||
#include <unistd.h>
|
||||
#include <sched.h>
|
||||
#include <assert.h>
|
||||
|
||||
#include <nuttx/irq.h>
|
||||
#include <nuttx/signal.h>
|
||||
#include <nuttx/semaphore.h>
|
||||
#include <nuttx/mm/iob.h>
|
||||
|
||||
#include "iob.h"
|
||||
|
||||
#ifdef CONFIG_IOB_NOTIFIER
|
||||
|
||||
/****************************************************************************
|
||||
* Private Types
|
||||
****************************************************************************/
|
||||
|
||||
/* This is the saved information for one IOB notification */
|
||||
|
||||
struct iob_notify_s
|
||||
{
|
||||
bool waiter; /* True if the waiter information is valid */
|
||||
uint8_t signo; /* The signal number to use when notifying the PID */
|
||||
pid_t pid; /* The PID to be notified when an IOB is available */
|
||||
};
|
||||
|
||||
/****************************************************************************
|
||||
* Private Data
|
||||
****************************************************************************/
|
||||
|
||||
/* This is a an array of threads waiting for an IOB. When an IOB becomes
|
||||
* available, *all* of the waiters in this thread will be signaled and the
|
||||
* entry will be marked invalid. If there are multiple waiters then only
|
||||
* the highest priority thread will get the IOB. Lower priority threads
|
||||
* will need to call iob_notify once again.
|
||||
*/
|
||||
|
||||
static struct iob_notify_s g_iob_notify[CONFIG_IOB_NWAITERS];
|
||||
|
||||
/* This semaphore is used as mutex to enforce mutually exlusive access to
|
||||
* the g_io_notify[] array.
|
||||
*/
|
||||
|
||||
static sem_t g_notify_sem = SEM_INITIALIZER(1);
|
||||
|
||||
/****************************************************************************
|
||||
* Public Functions
|
||||
****************************************************************************/
|
||||
|
||||
/****************************************************************************
|
||||
* Name: iob_notify_setup
|
||||
*
|
||||
* Description:
|
||||
* Set up to notify the specified PID with the provided signal number.
|
||||
*
|
||||
* NOTE: To avoid race conditions, the caller should set the sigprocmask
|
||||
* to block signal delivery. The signal will be delivered once the
|
||||
* signal is removed from the sigprocmask.
|
||||
*
|
||||
* Input Parameters:
|
||||
* pid - The PID to be notified. If a zero value is provided, then the
|
||||
* PID of the calling thread will be used.
|
||||
* signo - The signal number to use with the notification.
|
||||
*
|
||||
* Returned Value:
|
||||
* > 0 - There are already free IOBs and this this number of free IOBs
|
||||
* (CAUTION: This value is volatile). No signal notification
|
||||
* will be provided.
|
||||
* == 0 - There are no free IOBs. A signal will be sent to 'pid' when
|
||||
* at least one IOB is available. That IOB is *not* reserved for
|
||||
* the caller. Hence, due to race conditions, it could be taken
|
||||
* by some other task. In that event, the caller should call
|
||||
* sig_notify again.
|
||||
* < 0 - An unexpected error occurred and no signal will be sent. The
|
||||
* returned value is a negated errno value that indicates the
|
||||
* nature of the failure.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
int iob_notify_setup(int pid, int signo)
|
||||
{
|
||||
int ret;
|
||||
int i;
|
||||
|
||||
/* If the pid is zero, then use the pid of the calling thread */
|
||||
|
||||
if (pid <= 0)
|
||||
{
|
||||
pid = getpid();
|
||||
}
|
||||
|
||||
/* Get exclusive access to the notifier array */
|
||||
|
||||
ret = nxsem_wait(&g_notify_sem);
|
||||
if (ret < 0)
|
||||
{
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* If there are already free IOBs, then just return the number of free
|
||||
* IOBs.
|
||||
*/
|
||||
|
||||
ret = iob_navail();
|
||||
if (ret <= 0)
|
||||
{
|
||||
/* Find a free entry in the g_iob_notify[] array */
|
||||
|
||||
ret = -ENOSPC;
|
||||
for (i = 0; i < CONFIG_IOB_NWAITERS; i++)
|
||||
{
|
||||
if (!g_iob_notify[i].waiter)
|
||||
{
|
||||
g_iob_notify[i].waiter = true;
|
||||
g_iob_notify[i].pid = pid;
|
||||
g_iob_notify[i].signo = signo;
|
||||
|
||||
ret = OK;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
(void)nxsem_post(&g_notify_sem);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/****************************************************************************
|
||||
* Name: iob_notify_teardown
|
||||
*
|
||||
* Description:
|
||||
* Eliminate an IOB notification previously setup by iob_notify_setup().
|
||||
* This function should only be called if the notification should be
|
||||
* aborted prior to the notification. The notification will automatically
|
||||
* be torn down after the signal is sent.
|
||||
*
|
||||
* Input Parameters:
|
||||
* pid - The PID whose notification will be torn down. If a zero value
|
||||
* is provided, then the PID of the calling thread will be used.
|
||||
*
|
||||
* Returned Value:
|
||||
* Zero (OK) is returned on success; a negated errno value is returned on
|
||||
* any failure.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
int iob_notify_teardown(int pid, int signo)
|
||||
{
|
||||
int ret;
|
||||
int i;
|
||||
|
||||
/* If the pid is zero, then use the pid of the calling thread */
|
||||
|
||||
if (pid <= 0)
|
||||
{
|
||||
pid = getpid();
|
||||
}
|
||||
|
||||
/* Get exclusive access to the notifier array */
|
||||
|
||||
ret = nxsem_wait(&g_notify_sem);
|
||||
if (ret < 0)
|
||||
{
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Find the entry matching this PID in the g_iob_notify[] array. We
|
||||
* assume that there is only one.
|
||||
*/
|
||||
|
||||
ret = -ENOENT;
|
||||
for (i = 0; i < CONFIG_IOB_NWAITERS; i++)
|
||||
{
|
||||
if (g_iob_notify[i].waiter && g_iob_notify[i].pid == pid)
|
||||
{
|
||||
g_iob_notify[i].waiter = false;
|
||||
ret = OK;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
(void)nxsem_post(&g_notify_sem);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/****************************************************************************
|
||||
* Name: iob_notify_signal
|
||||
*
|
||||
* Description:
|
||||
* An IOB has become available. Signal all threads waiting for an IOB
|
||||
* that an IOB is available.
|
||||
*
|
||||
* When an IOB becomes available, *all* of the waiters in this thread will
|
||||
* be signaled. If there are multiple waiters then only the highest
|
||||
* priority thread will get the IOB. Lower priority threads will need to
|
||||
* call iob_notify once again.
|
||||
*
|
||||
* Input Parameters:
|
||||
* None.
|
||||
*
|
||||
* Returned Value:
|
||||
* None.
|
||||
*
|
||||
****************************************************************************/
|
||||
|
||||
void iob_notify_signal(void)
|
||||
{
|
||||
int ret;
|
||||
int i;
|
||||
|
||||
/* Get exclusive access to the notifier array */
|
||||
|
||||
ret = nxsem_wait(&g_notify_sem);
|
||||
while (ret < 0)
|
||||
{
|
||||
DEBUGASSERT(ret == -EINTR || ret == -ECANCELED);
|
||||
}
|
||||
|
||||
/* Don't let any newly started threads block this thread until all of
|
||||
* the notifications and been sent.
|
||||
*/
|
||||
|
||||
sched_lock();
|
||||
|
||||
/* Find the entry matching this PID in the g_iob_notify[] array. We
|
||||
* assume that there is only one.
|
||||
*/
|
||||
|
||||
for (i = 0; i < CONFIG_IOB_NWAITERS; i++)
|
||||
{
|
||||
if (g_iob_notify[i].waiter)
|
||||
{
|
||||
/* Signal the waiter and free the entry */
|
||||
|
||||
(void)nxsig_kill(g_iob_notify[i].pid, g_iob_notify[i].signo);
|
||||
g_iob_notify[i].waiter = false;
|
||||
}
|
||||
}
|
||||
|
||||
sched_unlock();
|
||||
(void)nxsem_post(&g_notify_sem);
|
||||
}
|
||||
|
||||
#endif /* CONFIG_IOB_NOTIFIER */
|
||||
Loading…
Reference in New Issue