[dpdk-dev] [PATCH v2 2/5] mem: add API to obtain memory-backed file info

[Jianfeng Tan]

A new API named rte_eal_get_backfile_info() and a new data
struct back_file is added to obstain information of memory-
backed file info.

Signed-off-by: Huawei Xie <huawei.xie at intel.com>
Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
---
 lib/librte_eal/common/include/rte_memory.h | 16 ++++++++++++
 lib/librte_eal/linuxapp/eal/eal_memory.c   | 40 +++++++++++++++++++++++++++++-
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/common/include/rte_memory.h b/lib/librte_eal/common/include/rte_memory.h
index 587a25d..b09397e 100644
--- a/lib/librte_eal/common/include/rte_memory.h
+++ b/lib/librte_eal/common/include/rte_memory.h
@@ -109,6 +109,22 @@ struct rte_memseg {
 } __rte_packed;
 
 /**
+ * This struct is used to store information about memory-backed file that
+ * we mapped in memory initialization.
+ */
+struct back_file {
+	void *addr;         /**< virtual addr */
+	size_t size;        /**< the page size */
+	char filepath[PATH_MAX]; /**< path to backing file on filesystem */
+};
+
+/**
+  * Get the hugepage file information. Caller to free.
+  * Return number of hugepage files used.
+  */
+int rte_eal_get_backfile_info(struct back_file **);
+
+/**
  * Lock page in physical memory and prevent from swapping.
  *
  * @param virt
diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
index 68ef49a..a6b3616 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -743,6 +743,9 @@ sort_by_physaddr(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi)
 	return 0;
 }
 
+static struct hugepage_file *hugepage_files;
+static int num_hugepage_files;
+
 /*
  * Uses mmap to create a shared memory area for storage of data
  * Used in this file to store the hugepage file map on disk
@@ -760,9 +763,30 @@ create_shared_memory(const char *filename, const size_t mem_size)
 	}
 	retval = mmap(NULL, mem_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
 	close(fd);
+
+	hugepage_files = retval;
+	num_hugepage_files = mem_size / (sizeof(struct hugepage_file));
+
 	return retval;
 }
 
+int
+rte_eal_get_backfile_info(struct back_file **p)
+{
+	struct back_file *backfiles;
+	int i, num_backfiles = num_hugepage_files;
+
+	backfiles = malloc(sizeof(struct back_file) * num_backfiles);
+	for (i = 0; i < num_backfiles; ++i) {
+		backfiles[i].addr = hugepage_files[i].final_va;
+		backfiles[i].size = hugepage_files[i].size;
+		strcpy(backfiles[i].filepath, hugepage_files[i].filepath);
+	}
+
+	*p = backfiles;
+	return num_backfiles;
+}
+
 /*
  * this copies *active* hugepages from one hugepage table to another.
  * destination is typically the shared memory.
@@ -1148,8 +1172,22 @@ rte_eal_hugepage_init(void)
 		mcfg->memseg[0].len = internal_config.memory;
 		mcfg->memseg[0].socket_id = socket_id;
 
-		close(fd);
+		hugepage = create_shared_memory(eal_hugepage_info_path(),
+						sizeof(struct hugepage_file));
+		hugepage->orig_va = addr;
+		hugepage->final_va = addr;
+		hugepage->physaddr = rte_mem_virt2phy(addr);
+		/* Suppose we have a very huge hugefile here */
+		hugepage->size = internal_config.memory;
+		hugepage->socket_id = socket_id;
+		hugepage->file_id = 0;
+		hugepage->memseg_id = 0;
+#ifdef RTE_EAL_SINGLE_FILE_SEGMENTS
+		hugepage->repeated = internal_config.memory / pagesize;
+#endif
+		strncpy(hugepage->filepath, filepath, MAX_HUGEPAGE_PATH);
 
+		close(fd);
 		return 0;
 	}
 
-- 
2.1.4