diff --git a/memory.c b/memory.c
new file mode 100644
index 0000000..d8924a8
--- /dev/null
+++ b/memory.c
@@ -0,0 +1,108 @@
+/*
+ * Memory helpers
+ */
+#include <unistd.h>
+#include <sys/shm.h>
+#include <sys/mman.h>
+
+#include "fio.h"
+#include "os.h"
+
+extern unsigned long long mlock_size;
+static void *pinned_mem;
+
+void fio_unpin_memory(void)
+{
+	if (pinned_mem) {
+		if (munlock(pinned_mem, mlock_size) < 0)
+			perror("munlock");
+		munmap(pinned_mem, mlock_size);
+		pinned_mem = NULL;
+	}
+}
+
+int fio_pin_memory(void)
+{
+	unsigned long long phys_mem;
+
+	if (!mlock_size)
+		return 0;
+
+	/*
+	 * Don't allow mlock of more than real_mem-128MB
+	 */
+	phys_mem = os_phys_mem();
+	if (phys_mem) {
+		if ((mlock_size + 128 * 1024 * 1024) > phys_mem) {
+			mlock_size = phys_mem - 128 * 1024 * 1024;
+			fprintf(f_out, "fio: limiting mlocked memory to %lluMiB\n", mlock_size >> 20);
+		}
+	}
+
+	pinned_mem = mmap(NULL, mlock_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | OS_MAP_ANON, 0, 0);
+	if (pinned_mem == MAP_FAILED) {
+		perror("malloc locked mem");
+		pinned_mem = NULL;
+		return 1;
+	}
+	if (mlock(pinned_mem, mlock_size) < 0) {
+		perror("mlock");
+		munmap(pinned_mem, mlock_size);
+		pinned_mem = NULL;
+		return 1;
+	}
+
+	return 0;
+}
+
+/*
+ * Setup the buffer area we need for io.
+ */
+int allocate_io_mem(struct thread_data *td)
+{
+	if (td->mem_type == MEM_MALLOC)
+		td->orig_buffer = malloc(td->orig_buffer_size);
+	else if (td->mem_type == MEM_SHM) {
+		td->shm_id = shmget(IPC_PRIVATE, td->orig_buffer_size, IPC_CREAT | 0600);
+		if (td->shm_id < 0) {
+			td_verror(td, errno);
+			perror("shmget");
+			return 1;
+		}
+
+		td->orig_buffer = shmat(td->shm_id, NULL, 0);
+		if (td->orig_buffer == (void *) -1) {
+			td_verror(td, errno);
+			perror("shmat");
+			td->orig_buffer = NULL;
+			return 1;
+		}
+	} else if (td->mem_type == MEM_MMAP) {
+		td->orig_buffer = mmap(NULL, td->orig_buffer_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | OS_MAP_ANON, 0, 0);
+		if (td->orig_buffer == MAP_FAILED) {
+			td_verror(td, errno);
+			perror("mmap");
+			td->orig_buffer = NULL;
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+void free_io_mem(struct thread_data *td)
+{
+	if (td->mem_type == MEM_MALLOC)
+		free(td->orig_buffer);
+	else if (td->mem_type == MEM_SHM) {
+		struct shmid_ds sbuf;
+
+		shmdt(td->orig_buffer);
+		shmctl(td->shm_id, IPC_RMID, &sbuf);
+	} else if (td->mem_type == MEM_MMAP)
+		munmap(td->orig_buffer, td->orig_buffer_size);
+	else
+		log_err("Bad memory type %d\n", td->mem_type);
+
+	td->orig_buffer = NULL;
+}