Abhinav's work on usemem_hugepages.c

Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>

1 files changed, 51 insertions, 0 deletions

diff --git a/usemem_hugepages.c b/usemem_hugepages.c
new file mode 100644
index 0000000..00e3838
--- /dev/null
+++ b/usemem_hugepages.c
@@ -0,0 +1,51 @@
+/*
+ * code for allocating hugepages using shared memory segment
+ */
+
+#include "usemem_hugepages.h"
+#include <stdio.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+
+/* Initialize seg_id to 0 */
+int seg_id = 0;
+
+/* Set the shared memory segment to destruction */
+void shm_free(int seg_id)
+{
+	if (seg_id < 0) {
+		perror("Invalid seg_id\n");
+		exit(1);
+	} else
+		shmctl(seg_id, IPC_RMID, NULL);
+}
+
+/* Allocate huge pages using shm segment */
+unsigned long *allocate_hugepage_segment(unsigned long bytes)
+{
+	unsigned long *p;
+
+	if (!bytes) {
+		perror("invalid size\n");
+		exit(1);
+	}
+
+	/* create a shared sys V IPC shared object of size "bytes"*/
+	if ((seg_id = shmget(IPC_PRIVATE, bytes, SHM_HUGETLB | IPC_CREAT | SHM_R |SHM_W)) == -1) {
+		/* Check if the shmget call was successful */
+		fprintf(stderr, "Error creating shared segment: %s \n", strerror(errno));
+		exit(1);
+	} else { /* Attach the shared memory to callers virtual address space */
+		/* Check if the attachment was successful */
+		if ((p = shmat(seg_id, NULL, 0)) == (void *) -1) {
+			fprintf(stderr, "Error attaching shared memory: %s \n", strerror(errno));
+			shm_free(seg_id);
+			exit(1);
+		}
+	}
+
+	return p;
+}