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Re: [Minios-devel] [UNIKRAFT PATCH v2 3/3] lib/ukmpi: Introduce mailboxes with libukmpi
On 15.06.2018 11:27, Yuri Volchkov wrote:
Simon Kuenzer <simon.kuenzer@xxxxxxxxx> writes:
From: Sharan Santhanam <sharan.santhanam@xxxxxxxxx>
Initial implementation for inter-thread communication with mailboxes.
The implmentation is based on semaphores provided by libuklock.
Signed-off-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
Signed-off-by: Sharan Santhanam <sharan.santhanam@xxxxxxxxx>
---
lib/Config.uk | 1 +
lib/Makefile.uk | 1 +
lib/ukmpi/Config.uk | 18 +++++
lib/ukmpi/Makefile.uk | 6 ++
lib/ukmpi/export.syms | 7 ++
lib/ukmpi/include/uk/mbox.h | 67 +++++++++++++++++
lib/ukmpi/mbox.c | 176 ++++++++++++++++++++++++++++++++++++++++++++
7 files changed, 276 insertions(+)
create mode 100644 lib/ukmpi/Config.uk
create mode 100644 lib/ukmpi/Makefile.uk
create mode 100644 lib/ukmpi/export.syms
create mode 100644 lib/ukmpi/include/uk/mbox.h
create mode 100644 lib/ukmpi/mbox.c
diff --git a/lib/Config.uk b/lib/Config.uk
index 9e6b269..2f47fde 100644
--- a/lib/Config.uk
+++ b/lib/Config.uk
@@ -34,4 +34,5 @@ source "lib/uksched/Config.uk"
source "lib/ukschedcoop/Config.uk"
source "lib/fdt/Config.uk"
source "lib/uklock/Config.uk"
+source "lib/ukmpi/Config.uk"
source "lib/ukswrand/Config.uk"
diff --git a/lib/Makefile.uk b/lib/Makefile.uk
index a79ad0d..a632336 100644
--- a/lib/Makefile.uk
+++ b/lib/Makefile.uk
@@ -17,3 +17,4 @@ $(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/ukschedcoop))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/fdt))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/vfscore))
$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/uklock))
+$(eval $(call _import_lib,$(CONFIG_UK_BASE)/lib/ukmpi))
diff --git a/lib/ukmpi/Config.uk b/lib/ukmpi/Config.uk
new file mode 100644
index 0000000..474d377
--- /dev/null
+++ b/lib/ukmpi/Config.uk
@@ -0,0 +1,18 @@
+menuconfig LIBUKMPI
+ bool "ukmpi: Message Passing interface"
+ select LIBNOLIBC if !HAVE_LIBC
+ select LIBUKDEBUG
+ default n
+ help
+ Provide inter-thread communication.
+
+if LIBUKMPI
+ config LIBUKMPI_MBOX
+ bool "Mailboxes"
+ select LIBUKALLOC
+ select LIBUKLOCK
+ select LIBUKLOCK_SEMAPHORE
+ default n
+ help
+ Provide mailbox communication interface
+endif
diff --git a/lib/ukmpi/Makefile.uk b/lib/ukmpi/Makefile.uk
new file mode 100644
index 0000000..fc8a360
--- /dev/null
+++ b/lib/ukmpi/Makefile.uk
@@ -0,0 +1,6 @@
+$(eval $(call addlib_s,libukmpi,$(CONFIG_LIBUKMPI)))
+
+CINCLUDES-$(CONFIG_LIBUKMPI) += -I$(LIBUKMPI_BASE)/include
+CXXINCLUDES-$(CONFIG_LIBUKMPI) += -I$(LIBUKMPI_BASE)/include
+
+LIBUKMPI_SRCS-$(CONFIG_LIBUKMPI_MBOX) += $(LIBUKMPI_BASE)/mbox.c
diff --git a/lib/ukmpi/export.syms b/lib/ukmpi/export.syms
new file mode 100644
index 0000000..4c4c887
--- /dev/null
+++ b/lib/ukmpi/export.syms
@@ -0,0 +1,7 @@
+uk_mbox_create
+uk_mbox_free
+uk_mbox_post
+uk_mbox_post_try
+uk_mbox_post_to
+uk_mbox_recv_try
+uk_mbox_recv_to
diff --git a/lib/ukmpi/include/uk/mbox.h b/lib/ukmpi/include/uk/mbox.h
new file mode 100644
index 0000000..d2c48e5
--- /dev/null
+++ b/lib/ukmpi/include/uk/mbox.h
@@ -0,0 +1,67 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Authors: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
+ *
+ * Copyright (c) 2018, NEC Europe Ltd., NEC Corporation. All rights reserved.
+ *
+ * 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 of the copyright holder 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 HOLDER 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.
+ *
+ * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
+ */
+
+
+#ifndef __UK_MBOX_H__
+#define __UK_MBOX_H__
+
+#include <uk/config.h>
+
+#if CONFIG_LIBUKMPI_MBOX
+#include <errno.h>
+#include <uk/semaphore.h>
+#include <uk/alloc.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+struct uk_mbox;
+
+struct uk_mbox *uk_mbox_create(struct uk_alloc *a, size_t size);
+void uk_mbox_free(struct uk_alloc *a, struct uk_mbox *m);
+
+void uk_mbox_post(struct uk_mbox *m, void *msg);
+int uk_mbox_post_try(struct uk_mbox *m, void *msg);
+__nsec uk_mbox_post_to(struct uk_mbox *m, void *msg, __nsec timeout);
+
+int uk_mbox_recv_try(struct uk_mbox *m, void **msg);
+__nsec uk_mbox_recv_to(struct uk_mbox *m, void **msg, __nsec timeout);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif /* CONFIG_LIBMPI_UKMBOX */
+#endif /* __UK_MBOX_H__ */
diff --git a/lib/ukmpi/mbox.c b/lib/ukmpi/mbox.c
new file mode 100644
index 0000000..31546dd
--- /dev/null
+++ b/lib/ukmpi/mbox.c
@@ -0,0 +1,176 @@
+#include <uk/mbox.h>
+#include <uk/assert.h>
+#include <uk/arch/limits.h>
+
+struct uk_mbox {
+ size_t len;
+ struct uk_semaphore readsem;
+ long readpos;
+ struct uk_semaphore writesem;
+ long writepos;
+
+ void *msgs[];
+};
+
+struct uk_mbox *uk_mbox_create(struct uk_alloc *a, size_t size)
+{
+ struct uk_mbox *m;
+
+ UK_ASSERT(size <= __L_MAX);
+
+ m = uk_malloc(a, sizeof(*m) + (sizeof(void*) * (size + 1)));
+ if (!m)
+ return NULL;
+
+ m->len = size + 1;
+
+ uk_semaphore_init(&m->readsem, 0);
+ m->readpos = 0;
+
+ uk_semaphore_init(&m->writesem, (long) size);
+ m->writepos = 0;
+
+ uk_printd(DLVL_EXTRA, "Created mailbox %p\n", m);
+ return m;
+}
+
+/* Deallocates a mailbox. If there are messages still present in the
+ * mailbox when the mailbox is deallocated, it is an indication of a
+ * programming error in lwIP and the developer should be notified. */
+void uk_mbox_free(struct uk_alloc *a, struct uk_mbox *m)
+{
+ uk_printd(DLVL_EXTRA, "Release mailbox %p\n", m);
+
+ UK_ASSERT(a);
+ UK_ASSERT(m);
+ UK_ASSERT(m->readpos == m->writepos);
+
+ uk_free(a, m);
+}
In the follow up patch we probably would want to add walking through
remaining messages and killing them. Or sleeping util user will read
them all (with a deadline) >
This is good idea, but I suggest to do this with extra patches. We may
need to add some clever mechanism to correctly unblock blocked threads.
+
+/* Posts the "msg" to the mailbox, internal version that actually does the
+ * post. */
+static inline void _do_mbox_post(struct uk_mbox *m, void *msg)
+{
+ /* The caller got a semaphore token, so we are now allowed to increment
+ * writer, but we still need to prevent concurrency between writers
+ * (interrupt handler vs main) */
+ unsigned long irqf;
+
+ UK_ASSERT(m);
+
+ irqf = ukplat_lcpu_save_irqf();
+ m->msgs[m->writepos] = msg;
+ m->writepos = (m->writepos + 1) % m->len;
+ UK_ASSERT(m->readpos != m->writepos);
+ ukplat_lcpu_restore_irqf(irqf);
+ uk_printd(DLVL_EXTRA, "Posted message %p to mailbox %p\n", msg, m);
+
+ uk_semaphore_up(&m->readsem);
+}
+
+void uk_mbox_post(struct uk_mbox *m, void *msg)
+{
+ /* The caller got a semaphore token, so we are now allowed to increment
+ * writer, but we still need to prevent concurrency between writers
+ * (interrupt handler vs main) */
+ UK_ASSERT(m);
+
+ uk_semaphore_down(&m->writesem);
+ _do_mbox_post(m, msg);
+}
+
+int uk_mbox_post_try(struct uk_mbox *m, void *msg)
+{
+ UK_ASSERT(m);
+
+ if (!uk_semaphore_down_try(&m->writesem))
+ return -ENOBUFS;
+ _do_mbox_post(m, msg);
+ return 0;
+}
+
+__nsec uk_mbox_post_to(struct uk_mbox *m, void *msg, __nsec timeout)
+{
+ __nsec ret;
+
+ UK_ASSERT(m);
+
+ ret = uk_semaphore_down_to(&m->writesem, timeout);
+ if (ret != __NSEC_MAX)
+ _do_mbox_post(m, msg);
+ return ret;
+}
+
+/*
+ * Fetch a message from a mailbox. Internal version that actually does the
+ * fetch.
+ */
+static inline void *_do_mbox_recv(struct uk_mbox *m)
+{
+ unsigned long irqf;
+ void *ret;
+
+ uk_printd(DLVL_EXTRA, "Receive message from mailbox %p\n", m);
Should this message go after actual receiving is happened?
+ irqf = ukplat_lcpu_save_irqf();
+ UK_ASSERT(m->readpos != m->writepos);
+ ret = m->msgs[m->readpos];
+ m->readpos = (m->readpos + 1) % m->len;
+ ukplat_lcpu_restore_irqf(irqf);
+
+ uk_semaphore_up(&m->writesem);
+
+ return ret;
+}
+
+/* This is similar to uk_mbox_fetch, however if a message is not
+ * present in the mailbox, it immediately returns with the code
+ * SYS_MBOX_EMPTY. On success 0 is returned.
+ *
+ * To allow for efficient implementations, this can be defined as a
+ * function-like macro in sys_arch.h instead of a normal function. For
+ * example, a naive implementation could be:
+ * #define uk_mbox_tryfetch(mbox,msg) \
+ * uk_mbox_fetch(mbox,msg,1)
+ * although this would introduce unnecessary delays. */
+
+int uk_mbox_recv_try(struct uk_mbox *m, void **msg)
+{
+ void *rmsg;
+ UK_ASSERT(m);
+
+ if (!uk_semaphore_down_try(&m->readsem))
+ return -ENOMSG;
+
+ rmsg = _do_mbox_recv(m);
+ if (msg)
+ *msg = rmsg;
+ return 0;
+}
+
+
+/* Blocks the thread until a message arrives in the mailbox, but does
+ * not block the thread longer than "timeout" milliseconds (similar to
+ * the sys_arch_sem_wait() function). The "msg" argument is a result
+ * parameter that is set by the function (i.e., by doing "*msg =
+ * ptr"). The "msg" parameter maybe NULL to indicate that the message
+ * should be dropped.
+ *
+ * The return values are the same as for the sys_arch_sem_wait() function:
+ * Number of milliseconds spent waiting or SYS_ARCH_TIMEOUT if there was a
+ * timeout. */
+__nsec uk_mbox_recv_to(struct uk_mbox *m, void **msg, __nsec timeout)
+{
+ void *rmsg = NULL;
+ __nsec ret;
+
+ UK_ASSERT(m);
+
+ ret = uk_semaphore_down_to(&m->readsem, timeout);
+ if (ret != __NSEC_MAX)
+ rmsg = _do_mbox_recv(m);
+
+ if (msg)
+ *msg = rmsg;
+ return ret;
+}
--
2.7.4
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