[dpdk-dev] [PATCH v2 19/41] eal: add API to check if memory is 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/bsdapp/eal/Makefile          |  1 +
 lib/librte_eal/common/eal_common_memalloc.c | 49 +++++++++++++++++++++++++++++
 lib/librte_eal/common/eal_memalloc.h        |  5 +++
 lib/librte_eal/common/meson.build           |  1 +
 lib/librte_eal/linuxapp/eal/Makefile        |  1 +
 5 files changed, 57 insertions(+)
 create mode 100644 lib/librte_eal/common/eal_common_memalloc.c

diff --git a/lib/librte_eal/bsdapp/eal/Makefile b/lib/librte_eal/bsdapp/eal/Makefile
index 19f9322..907e30d 100644
--- a/lib/librte_eal/bsdapp/eal/Makefile
+++ b/lib/librte_eal/bsdapp/eal/Makefile
@@ -41,6 +41,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_timer.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_memzone.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_log.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_launch.c
+SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_memalloc.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_memory.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_tailqs.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_errno.c
diff --git a/lib/librte_eal/common/eal_common_memalloc.c b/lib/librte_eal/common/eal_common_memalloc.c
new file mode 100644
index 0000000..62e8c16
--- /dev/null
+++ b/lib/librte_eal/common/eal_common_memalloc.c
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2017-2018 Intel Corporation
+ */
+
+#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"
+
+bool
+eal_memalloc_is_contig(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 adf59c4..08ba70e 100644
--- a/lib/librte_eal/common/eal_memalloc.h
+++ b/lib/librte_eal/common/eal_memalloc.h
@@ -8,6 +8,7 @@
 #include <stdbool.h>
 
 #include <rte_memory.h>
+#include <rte_eal_memconfig.h>
 
 struct rte_memseg *
 eal_memalloc_alloc_page(uint64_t size, int socket);
@@ -19,4 +20,8 @@ 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(struct rte_memseg_list *msl, void *start,
+		size_t len);
+
 #endif // EAL_MEMALLOC_H
diff --git a/lib/librte_eal/common/meson.build b/lib/librte_eal/common/meson.build
index 7d02191..a1ada24 100644
--- a/lib/librte_eal/common/meson.build
+++ b/lib/librte_eal/common/meson.build
@@ -16,6 +16,7 @@ common_sources = files(
 	'eal_common_launch.c',
 	'eal_common_lcore.c',
 	'eal_common_log.c',
+	'eal_common_memalloc.c',
 	'eal_common_memory.c',
 	'eal_common_memzone.c',
 	'eal_common_options.c',
diff --git a/lib/librte_eal/linuxapp/eal/Makefile b/lib/librte_eal/linuxapp/eal/Makefile
index af6b9be..5380ba8 100644
--- a/lib/librte_eal/linuxapp/eal/Makefile
+++ b/lib/librte_eal/linuxapp/eal/Makefile
@@ -49,6 +49,7 @@ 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