[dpdk-dev] [PATCH 15/23] eal: add API to check if memory is physically contiguous

[Anatoly Burakov]

This will be helpful down the line when we implement support for
allocating physically contiguous memory. We can no longer guarantee
physically contiguous memory unless we're in IOVA_AS_VA mode, but
we can certainly try and see if we succeed. In addition, this would
be useful for e.g. PMD's who may allocate chunks that are smaller
than the pagesize, but they must not cross the page boundary, in
which case we will be able to accommodate that request.

Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 lib/librte_eal/common/eal_common_memalloc.c | 79 +++++++++++++++++++++++++++++
 lib/librte_eal/common/eal_memalloc.h        |  5 ++
 lib/librte_eal/linuxapp/eal/Makefile        |  1 +
 3 files changed, 85 insertions(+)
 create mode 100755 lib/librte_eal/common/eal_common_memalloc.c

diff --git a/lib/librte_eal/common/eal_common_memalloc.c b/lib/librte_eal/common/eal_common_memalloc.c
new file mode 100755
index 0000000..395753a
--- /dev/null
+++ b/lib/librte_eal/common/eal_common_memalloc.c
@@ -0,0 +1,79 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2017 Intel 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:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * 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.
+ *     * Neither the name of Intel Corporation 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.
+ */
+
+#include <rte_lcore.h>
+#include <rte_fbarray.h>
+#include <rte_memzone.h>
+#include <rte_memory.h>
+#include <rte_eal_memconfig.h>
+
+#include "eal_private.h"
+#include "eal_internal_cfg.h"
+#include "eal_memalloc.h"
+
+// TODO: secondary
+// TODO: 32-bit
+
+bool
+eal_memalloc_is_contig(const struct rte_memseg_list *msl, void *start,
+		size_t len) {
+	const struct rte_memseg *ms;
+	uint64_t page_sz;
+	void *end;
+	int start_page, end_page, cur_page;
+	rte_iova_t expected;
+
+	/* for legacy memory, it's always contiguous */
+	if (internal_config.legacy_mem)
+		return true;
+
+	/* figure out how many pages we need to fit in current data */
+	page_sz = msl->hugepage_sz;
+	end = RTE_PTR_ADD(start, len);
+
+	start_page = RTE_PTR_DIFF(start, msl->base_va) / page_sz;
+	end_page = RTE_PTR_DIFF(end, msl->base_va) / page_sz;
+
+	/* now, look for contiguous memory */
+	ms = rte_fbarray_get(&msl->memseg_arr, start_page);
+	expected = ms->iova + page_sz;
+
+	for (cur_page = start_page + 1; cur_page < end_page;
+			cur_page++, expected += page_sz) {
+		ms = rte_fbarray_get(&msl->memseg_arr, cur_page);
+
+		if (ms->iova != expected)
+			return false;
+	}
+
+	return true;
+}
diff --git a/lib/librte_eal/common/eal_memalloc.h b/lib/librte_eal/common/eal_memalloc.h
index 47e4367..04f9b72 100755
--- a/lib/librte_eal/common/eal_memalloc.h
+++ b/lib/librte_eal/common/eal_memalloc.h
@@ -36,6 +36,7 @@
 #include <stdbool.h>
 
 #include <rte_memory.h>
+#include <rte_eal_memconfig.h>
 
 struct rte_memseg *
 eal_memalloc_alloc_page(uint64_t size, int socket);
@@ -47,4 +48,8 @@ eal_memalloc_alloc_page_bulk(struct rte_memseg **ms, int n, uint64_t size,
 int
 eal_memalloc_free_page(struct rte_memseg *ms);
 
+bool
+eal_memalloc_is_contig(const struct rte_memseg_list *msl, void *start,
+		size_t len);
+
 #endif // EAL_MEMALLOC_H
diff --git a/lib/librte_eal/linuxapp/eal/Makefile b/lib/librte_eal/linuxapp/eal/Makefile
index 88f10e9..c1fc557 100644
--- a/lib/librte_eal/linuxapp/eal/Makefile
+++ b/lib/librte_eal/linuxapp/eal/Makefile
@@ -75,6 +75,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_timer.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_memzone.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_log.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_launch.c
+SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_memalloc.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_memory.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_tailqs.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_errno.c
-- 
2.7.4