memory.c

/*
 * Memory helpers
 */
#include <unistd.h>
#include <sys/shm.h>
#include <sys/mman.h>

#include "fio.h"

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;
			log_info("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->o.mem_type == MEM_MALLOC)
		td->orig_buffer = malloc(td->orig_buffer_size);
	else if (td->o.mem_type == MEM_SHM || td->o.mem_type == MEM_SHMHUGE) {
		int flags = IPC_CREAT | SHM_R | SHM_W;

		if (td->o.mem_type == MEM_SHMHUGE)
			flags |= SHM_HUGETLB;

		td->shm_id = shmget(IPC_PRIVATE, td->orig_buffer_size, flags);
		if (td->shm_id < 0) {
			td_verror(td, errno, "shmget");
			if (geteuid() != 0 && errno == ENOMEM)
				log_err("fio: you may need to run this job as root\n");
			if (errno == EINVAL && td->o.mem_type == MEM_SHMHUGE)
				log_err("fio: check that you have free huge pages and that hugepage-size is correct.\n");
			
			return 1;
		}

		td->orig_buffer = shmat(td->shm_id, NULL, 0);
		if (td->orig_buffer == (void *) -1) {
			td_verror(td, errno, "shmat");
			td->orig_buffer = NULL;
			return 1;
		}
	} else if (td->o.mem_type == MEM_MMAP ||
		   td->o.mem_type == MEM_MMAPHUGE) {
		int flags = MAP_PRIVATE;

		td->mmapfd = 0;

		if (td->mmapfile) {
			td->mmapfd = open(td->mmapfile, O_RDWR|O_CREAT, 0644);

			if (td->mmapfd < 0) {
				td_verror(td, errno, "open mmap file");
				td->orig_buffer = NULL;
				return 1;
			}
			if (ftruncate(td->mmapfd, td->orig_buffer_size) < 0) {
				td_verror(td, errno, "truncate mmap file");
				td->orig_buffer = NULL;
				return 1;
			}
		} else
			flags |= OS_MAP_ANON;

		td->orig_buffer = mmap(NULL, td->orig_buffer_size, PROT_READ | PROT_WRITE, flags, td->mmapfd, 0);
		if (td->orig_buffer == MAP_FAILED) {
			td_verror(td, errno, "mmap");
			td->orig_buffer = NULL;
			if (td->mmapfd) {
				close(td->mmapfd);
				unlink(td->mmapfile);
			}
				
			return 1;
		}
	}

	return 0;
}

void free_io_mem(struct thread_data *td)
{
	if (td->o.mem_type == MEM_MALLOC)
		free(td->orig_buffer);
	else if (td->o.mem_type == MEM_SHM || td->o.mem_type == MEM_SHMHUGE) {
		struct shmid_ds sbuf;

		shmdt(td->orig_buffer);
		shmctl(td->shm_id, IPC_RMID, &sbuf);
	} else if (td->o.mem_type == MEM_MMAP ||
		   td->o.mem_type == MEM_MMAPHUGE) {
		munmap(td->orig_buffer, td->orig_buffer_size);
		if (td->mmapfile) {
			close(td->mmapfd);
			unlink(td->mmapfile);
			free(td->mmapfile);
		}
	} else
		log_err("Bad memory type %u\n", td->o.mem_type);

	td->orig_buffer = NULL;
}