New upstream version 18.08upstream/18.08

Change-Id: I32fdf5e5016556d9c0a6d88ddaf1fc468961790a
Signed-off-by: Luca Boccassi <luca.boccassi@gmail.com>

1 files changed, 1363 insertions, 0 deletions

diff --git a/lib/librte_eal/linuxapp/eal/eal_memalloc.c b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
new file mode 100644
index 00000000..aa95551a
--- /dev/null
+++ b/lib/librte_eal/linuxapp/eal/eal_memalloc.c
@@ -0,0 +1,1363 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2017-2018 Intel Corporation
+ */
+
+#define _FILE_OFFSET_BITS 64
+#include <errno.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/queue.h>
+#include <sys/file.h>
+#include <unistd.h>
+#include <limits.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <signal.h>
+#include <setjmp.h>
+#ifdef RTE_EAL_NUMA_AWARE_HUGEPAGES
+#include <numa.h>
+#include <numaif.h>
+#endif
+#include <linux/falloc.h>
+#include <linux/mman.h> /* for hugetlb-related mmap flags */
+
+#include <rte_common.h>
+#include <rte_log.h>
+#include <rte_eal_memconfig.h>
+#include <rte_eal.h>
+#include <rte_memory.h>
+#include <rte_spinlock.h>
+
+#include "eal_filesystem.h"
+#include "eal_internal_cfg.h"
+#include "eal_memalloc.h"
+#include "eal_private.h"
+
+const int anonymous_hugepages_supported =
+#ifdef MAP_HUGE_SHIFT
+		1;
+#define RTE_MAP_HUGE_SHIFT MAP_HUGE_SHIFT
+#else
+		0;
+#define RTE_MAP_HUGE_SHIFT 26
+#endif
+
+/*
+ * not all kernel version support fallocate on hugetlbfs, so fall back to
+ * ftruncate and disallow deallocation if fallocate is not supported.
+ */
+static int fallocate_supported = -1; /* unknown */
+
+/* for single-file segments, we need some kind of mechanism to keep track of
+ * which hugepages can be freed back to the system, and which cannot. we cannot
+ * use flock() because they don't allow locking parts of a file, and we cannot
+ * use fcntl() due to issues with their semantics, so we will have to rely on a
+ * bunch of lockfiles for each page.
+ *
+ * we cannot know how many pages a system will have in advance, but we do know
+ * that they come in lists, and we know lengths of these lists. so, simply store
+ * a malloc'd array of fd's indexed by list and segment index.
+ *
+ * they will be initialized at startup, and filled as we allocate/deallocate
+ * segments. also, use this to track memseg list proper fd.
+ */
+static struct {
+	int *fds; /**< dynamically allocated array of segment lock fd's */
+	int memseg_list_fd; /**< memseg list fd */
+	int len; /**< total length of the array */
+	int count; /**< entries used in an array */
+} lock_fds[RTE_MAX_MEMSEG_LISTS];
+
+/** local copy of a memory map, used to synchronize memory hotplug in MP */
+static struct rte_memseg_list local_memsegs[RTE_MAX_MEMSEG_LISTS];
+
+static sigjmp_buf huge_jmpenv;
+
+static void __rte_unused huge_sigbus_handler(int signo __rte_unused)
+{
+	siglongjmp(huge_jmpenv, 1);
+}
+
+/* Put setjmp into a wrap method to avoid compiling error. Any non-volatile,
+ * non-static local variable in the stack frame calling sigsetjmp might be
+ * clobbered by a call to longjmp.
+ */
+static int __rte_unused huge_wrap_sigsetjmp(void)
+{
+	return sigsetjmp(huge_jmpenv, 1);
+}
+
+static struct sigaction huge_action_old;
+static int huge_need_recover;
+
+static void __rte_unused
+huge_register_sigbus(void)
+{
+	sigset_t mask;
+	struct sigaction action;
+
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGBUS);
+	action.sa_flags = 0;
+	action.sa_mask = mask;
+	action.sa_handler = huge_sigbus_handler;
+
+	huge_need_recover = !sigaction(SIGBUS, &action, &huge_action_old);
+}
+
+static void __rte_unused
+huge_recover_sigbus(void)
+{
+	if (huge_need_recover) {
+		sigaction(SIGBUS, &huge_action_old, NULL);
+		huge_need_recover = 0;
+	}
+}
+
+#ifdef RTE_EAL_NUMA_AWARE_HUGEPAGES
+static bool
+check_numa(void)
+{
+	bool ret = true;
+	/* Check if kernel supports NUMA. */
+	if (numa_available() != 0) {
+		RTE_LOG(DEBUG, EAL, "NUMA is not supported.\n");
+		ret = false;
+	}
+	return ret;
+}
+
+static void
+prepare_numa(int *oldpolicy, struct bitmask *oldmask, int socket_id)
+{
+	RTE_LOG(DEBUG, EAL, "Trying to obtain current memory policy.\n");
+	if (get_mempolicy(oldpolicy, oldmask->maskp,
+			  oldmask->size + 1, 0, 0) < 0) {
+		RTE_LOG(ERR, EAL,
+			"Failed to get current mempolicy: %s. "
+			"Assuming MPOL_DEFAULT.\n", strerror(errno));
+		oldpolicy = MPOL_DEFAULT;
+	}
+	RTE_LOG(DEBUG, EAL,
+		"Setting policy MPOL_PREFERRED for socket %d\n",
+		socket_id);
+	numa_set_preferred(socket_id);
+}
+
+static void
+restore_numa(int *oldpolicy, struct bitmask *oldmask)
+{
+	RTE_LOG(DEBUG, EAL,
+		"Restoring previous memory policy: %d\n", *oldpolicy);
+	if (*oldpolicy == MPOL_DEFAULT) {
+		numa_set_localalloc();
+	} else if (set_mempolicy(*oldpolicy, oldmask->maskp,
+				 oldmask->size + 1) < 0) {
+		RTE_LOG(ERR, EAL, "Failed to restore mempolicy: %s\n",
+			strerror(errno));
+		numa_set_localalloc();
+	}
+	numa_free_cpumask(oldmask);
+}
+#endif
+
+/*
+ * uses fstat to report the size of a file on disk
+ */
+static off_t
+get_file_size(int fd)
+{
+	struct stat st;
+	if (fstat(fd, &st) < 0)
+		return 0;
+	return st.st_size;
+}
+
+/* returns 1 on successful lock, 0 on unsuccessful lock, -1 on error */
+static int lock(int fd, int type)
+{
+	int ret;
+
+	/* flock may be interrupted */
+	do {
+		ret = flock(fd, type | LOCK_NB);
+	} while (ret && errno == EINTR);
+
+	if (ret && errno == EWOULDBLOCK) {
+		/* couldn't lock */
+		return 0;
+	} else if (ret) {
+		RTE_LOG(ERR, EAL, "%s(): error calling flock(): %s\n",
+			__func__, strerror(errno));
+		return -1;
+	}
+	/* lock was successful */
+	return 1;
+}
+
+static int get_segment_lock_fd(int list_idx, int seg_idx)
+{
+	char path[PATH_MAX] = {0};
+	int fd;
+
+	if (list_idx < 0 || list_idx >= (int)RTE_DIM(lock_fds))
+		return -1;
+	if (seg_idx < 0 || seg_idx >= lock_fds[list_idx].len)
+		return -1;
+
+	fd = lock_fds[list_idx].fds[seg_idx];
+	/* does this lock already exist? */
+	if (fd >= 0)
+		return fd;
+
+	eal_get_hugefile_lock_path(path, sizeof(path),
+			list_idx * RTE_MAX_MEMSEG_PER_LIST + seg_idx);
+
+	fd = open(path, O_CREAT | O_RDWR, 0660);
+	if (fd < 0) {
+		RTE_LOG(ERR, EAL, "%s(): error creating lockfile '%s': %s\n",
+			__func__, path, strerror(errno));
+		return -1;
+	}
+	/* take out a read lock */
+	if (lock(fd, LOCK_SH) != 1) {
+		RTE_LOG(ERR, EAL, "%s(): failed to take out a readlock on '%s': %s\n",
+			__func__, path, strerror(errno));
+		close(fd);
+		return -1;
+	}
+	/* store it for future reference */
+	lock_fds[list_idx].fds[seg_idx] = fd;
+	lock_fds[list_idx].count++;
+	return fd;
+}
+
+static int unlock_segment(int list_idx, int seg_idx)
+{
+	int fd, ret;
+
+	if (list_idx < 0 || list_idx >= (int)RTE_DIM(lock_fds))
+		return -1;
+	if (seg_idx < 0 || seg_idx >= lock_fds[list_idx].len)
+		return -1;
+
+	fd = lock_fds[list_idx].fds[seg_idx];
+
+	/* upgrade lock to exclusive to see if we can remove the lockfile */
+	ret = lock(fd, LOCK_EX);
+	if (ret == 1) {
+		/* we've succeeded in taking exclusive lock, this lockfile may
+		 * be removed.
+		 */
+		char path[PATH_MAX] = {0};
+		eal_get_hugefile_lock_path(path, sizeof(path),
+				list_idx * RTE_MAX_MEMSEG_PER_LIST + seg_idx);
+		if (unlink(path)) {
+			RTE_LOG(ERR, EAL, "%s(): error removing lockfile '%s': %s\n",
+					__func__, path, strerror(errno));
+		}
+	}
+	/* we don't want to leak the fd, so even if we fail to lock, close fd
+	 * and remove it from list anyway.
+	 */
+	close(fd);
+	lock_fds[list_idx].fds[seg_idx] = -1;
+	lock_fds[list_idx].count--;
+
+	if (ret < 0)
+		return -1;
+	return 0;
+}
+
+static int
+get_seg_fd(char *path, int buflen, struct hugepage_info *hi,
+		unsigned int list_idx, unsigned int seg_idx)
+{
+	int fd;
+
+	if (internal_config.single_file_segments) {
+		/* create a hugepage file path */
+		eal_get_hugefile_path(path, buflen, hi->hugedir, list_idx);
+
+		fd = lock_fds[list_idx].memseg_list_fd;
+
+		if (fd < 0) {
+			fd = open(path, O_CREAT | O_RDWR, 0600);
+			if (fd < 0) {
+				RTE_LOG(ERR, EAL, "%s(): open failed: %s\n",
+					__func__, strerror(errno));
+				return -1;
+			}
+			/* take out a read lock and keep it indefinitely */
+			if (lock(fd, LOCK_SH) < 0) {
+				RTE_LOG(ERR, EAL, "%s(): lock failed: %s\n",
+					__func__, strerror(errno));
+				close(fd);
+				return -1;
+			}
+			lock_fds[list_idx].memseg_list_fd = fd;
+		}
+	} else {
+		/* create a hugepage file path */
+		eal_get_hugefile_path(path, buflen, hi->hugedir,
+				list_idx * RTE_MAX_MEMSEG_PER_LIST + seg_idx);
+		fd = open(path, O_CREAT | O_RDWR, 0600);
+		if (fd < 0) {
+			RTE_LOG(DEBUG, EAL, "%s(): open failed: %s\n", __func__,
+					strerror(errno));
+			return -1;
+		}
+		/* take out a read lock */
+		if (lock(fd, LOCK_SH) < 0) {
+			RTE_LOG(ERR, EAL, "%s(): lock failed: %s\n",
+				__func__, strerror(errno));
+			close(fd);
+			return -1;
+		}
+	}
+	return fd;
+}
+
+static int
+resize_hugefile(int fd, char *path, int list_idx, int seg_idx,
+		uint64_t fa_offset, uint64_t page_sz, bool grow)
+{
+	bool again = false;
+	do {
+		if (fallocate_supported == 0) {
+			/* we cannot deallocate memory if fallocate() is not
+			 * supported, and hugepage file is already locked at
+			 * creation, so no further synchronization needed.
+			 */
+
+			if (!grow) {
+				RTE_LOG(DEBUG, EAL, "%s(): fallocate not supported, not freeing page back to the system\n",
+					__func__);
+				return -1;
+			}
+			uint64_t new_size = fa_offset + page_sz;
+			uint64_t cur_size = get_file_size(fd);
+
+			/* fallocate isn't supported, fall back to ftruncate */
+			if (new_size > cur_size &&
+					ftruncate(fd, new_size) < 0) {
+				RTE_LOG(DEBUG, EAL, "%s(): ftruncate() failed: %s\n",
+					__func__, strerror(errno));
+				return -1;
+			}
+		} else {
+			int flags = grow ? 0 : FALLOC_FL_PUNCH_HOLE |
+					FALLOC_FL_KEEP_SIZE;
+			int ret, lock_fd;
+
+			/* if fallocate() is supported, we need to take out a
+			 * read lock on allocate (to prevent other processes
+			 * from deallocating this page), and take out a write
+			 * lock on deallocate (to ensure nobody else is using
+			 * this page).
+			 *
+			 * read locks on page itself are already taken out at
+			 * file creation, in get_seg_fd().
+			 *
+			 * we cannot rely on simple use of flock() call, because
+			 * we need to be able to lock a section of the file,
+			 * and we cannot use fcntl() locks, because of numerous
+			 * problems with their semantics, so we will use
+			 * deterministically named lock files for each section
+			 * of the file.
+			 *
+			 * if we're shrinking the file, we want to upgrade our
+			 * lock from shared to exclusive.
+			 *
+			 * lock_fd is an fd for a lockfile, not for the segment
+			 * list.
+			 */
+			lock_fd = get_segment_lock_fd(list_idx, seg_idx);
+
+			if (!grow) {
+				/* we are using this lockfile to determine
+				 * whether this particular page is locked, as we
+				 * are in single file segments mode and thus
+				 * cannot use regular flock() to get this info.
+				 *
+				 * we want to try and take out an exclusive lock
+				 * on the lock file to determine if we're the
+				 * last ones using this page, and if not, we
+				 * won't be shrinking it, and will instead exit
+				 * prematurely.
+				 */
+				ret = lock(lock_fd, LOCK_EX);
+
+				/* drop the lock on the lockfile, so that even
+				 * if we couldn't shrink the file ourselves, we
+				 * are signalling to other processes that we're
+				 * no longer using this page.
+				 */
+				if (unlock_segment(list_idx, seg_idx))
+					RTE_LOG(ERR, EAL, "Could not unlock segment\n");
+
+				/* additionally, if this was the last lock on
+				 * this segment list, we can safely close the
+				 * page file fd, so that one of the processes
+				 * could then delete the file after shrinking.
+				 */
+				if (ret < 1 && lock_fds[list_idx].count == 0) {
+					close(fd);
+					lock_fds[list_idx].memseg_list_fd = -1;
+				}
+
+				if (ret < 0) {
+					RTE_LOG(ERR, EAL, "Could not lock segment\n");
+					return -1;
+				}
+				if (ret == 0)
+					/* failed to lock, not an error. */
+					return 0;
+			}
+
+			/* grow or shrink the file */
+			ret = fallocate(fd, flags, fa_offset, page_sz);
+
+			if (ret < 0) {
+				if (fallocate_supported == -1 &&
+						errno == ENOTSUP) {
+					RTE_LOG(ERR, EAL, "%s(): fallocate() not supported, hugepage deallocation will be disabled\n",
+						__func__);
+					again = true;
+					fallocate_supported = 0;
+				} else {
+					RTE_LOG(DEBUG, EAL, "%s(): fallocate() failed: %s\n",
+						__func__,
+						strerror(errno));
+					return -1;
+				}
+			} else {
+				fallocate_supported = 1;
+
+				/* we've grew/shrunk the file, and we hold an
+				 * exclusive lock now. check if there are no
+				 * more segments active in this segment list,
+				 * and remove the file if there aren't.
+				 */
+				if (lock_fds[list_idx].count == 0) {
+					if (unlink(path))
+						RTE_LOG(ERR, EAL, "%s(): unlinking '%s' failed: %s\n",
+							__func__, path,
+							strerror(errno));
+					close(fd);
+					lock_fds[list_idx].memseg_list_fd = -1;
+				}
+			}
+		}
+	} while (again);
+	return 0;
+}
+
+static int
+alloc_seg(struct rte_memseg *ms, void *addr, int socket_id,
+		struct hugepage_info *hi, unsigned int list_idx,
+		unsigned int seg_idx)
+{
+#ifdef RTE_EAL_NUMA_AWARE_HUGEPAGES
+	int cur_socket_id = 0;
+#endif
+	uint64_t map_offset;
+	rte_iova_t iova;
+	void *va;
+	char path[PATH_MAX];
+	int ret = 0;
+	int fd;
+	size_t alloc_sz;
+	int flags;
+	void *new_addr;
+
+	alloc_sz = hi->hugepage_sz;
+	if (!internal_config.single_file_segments &&
+			internal_config.in_memory &&
+			anonymous_hugepages_supported) {
+		int log2, flags;
+
+		log2 = rte_log2_u32(alloc_sz);
+		/* as per mmap() manpage, all page sizes are log2 of page size
+		 * shifted by MAP_HUGE_SHIFT
+		 */
+		flags = (log2 << RTE_MAP_HUGE_SHIFT) | MAP_HUGETLB | MAP_FIXED |
+				MAP_PRIVATE | MAP_ANONYMOUS;
+		fd = -1;
+		va = mmap(addr, alloc_sz, PROT_READ | PROT_WRITE, flags, -1, 0);
+
+		/* single-file segments codepath will never be active because
+		 * in-memory mode is incompatible with it and it's stopped at
+		 * EAL initialization stage, however the compiler doesn't know
+		 * that and complains about map_offset being used uninitialized
+		 * on failure codepaths while having in-memory mode enabled. so,
+		 * assign a value here.
+		 */
+		map_offset = 0;
+	} else {
+		/* takes out a read lock on segment or segment list */
+		fd = get_seg_fd(path, sizeof(path), hi, list_idx, seg_idx);
+		if (fd < 0) {
+			RTE_LOG(ERR, EAL, "Couldn't get fd on hugepage file\n");
+			return -1;
+		}
+
+		if (internal_config.single_file_segments) {
+			map_offset = seg_idx * alloc_sz;
+			ret = resize_hugefile(fd, path, list_idx, seg_idx,
+					map_offset, alloc_sz, true);
+			if (ret < 0)
+				goto resized;
+		} else {
+			map_offset = 0;
+			if (ftruncate(fd, alloc_sz) < 0) {
+				RTE_LOG(DEBUG, EAL, "%s(): ftruncate() failed: %s\n",
+					__func__, strerror(errno));
+				goto resized;
+			}
+			if (internal_config.hugepage_unlink) {
+				if (unlink(path)) {
+					RTE_LOG(DEBUG, EAL, "%s(): unlink() failed: %s\n",
+						__func__, strerror(errno));
+					goto resized;
+				}
+			}
+		}
+
+		/*
+		 * map the segment, and populate page tables, the kernel fills
+		 * this segment with zeros if it's a new page.
+		 */
+		va = mmap(addr, alloc_sz, PROT_READ | PROT_WRITE,
+				MAP_SHARED | MAP_POPULATE | MAP_FIXED, fd,
+				map_offset);
+	}
+
+	if (va == MAP_FAILED) {
+		RTE_LOG(DEBUG, EAL, "%s(): mmap() failed: %s\n", __func__,
+			strerror(errno));
+		/* mmap failed, but the previous region might have been
+		 * unmapped anyway. try to remap it
+		 */
+		goto unmapped;
+	}
+	if (va != addr) {
+		RTE_LOG(DEBUG, EAL, "%s(): wrong mmap() address\n", __func__);
+		munmap(va, alloc_sz);
+		goto resized;
+	}
+
+	/* In linux, hugetlb limitations, like cgroup, are
+	 * enforced at fault time instead of mmap(), even
+	 * with the option of MAP_POPULATE. Kernel will send
+	 * a SIGBUS signal. To avoid to be killed, save stack
+	 * environment here, if SIGBUS happens, we can jump
+	 * back here.
+	 */
+	if (huge_wrap_sigsetjmp()) {
+		RTE_LOG(DEBUG, EAL, "SIGBUS: Cannot mmap more hugepages of size %uMB\n",
+			(unsigned int)(alloc_sz >> 20));
+		goto mapped;
+	}
+
+	/* we need to trigger a write to the page to enforce page fault and
+	 * ensure that page is accessible to us, but we can't overwrite value
+	 * that is already there, so read the old value, and write itback.
+	 * kernel populates the page with zeroes initially.
+	 */
+	*(volatile int *)addr = *(volatile int *)addr;
+
+	iova = rte_mem_virt2iova(addr);
+	if (iova == RTE_BAD_PHYS_ADDR) {
+		RTE_LOG(DEBUG, EAL, "%s(): can't get IOVA addr\n",
+			__func__);
+		goto mapped;
+	}
+
+#ifdef RTE_EAL_NUMA_AWARE_HUGEPAGES
+	move_pages(getpid(), 1, &addr, NULL, &cur_socket_id, 0);
+
+	if (cur_socket_id != socket_id) {
+		RTE_LOG(DEBUG, EAL,
+				"%s(): allocation happened on wrong socket (wanted %d, got %d)\n",
+			__func__, socket_id, cur_socket_id);
+		goto mapped;
+	}
+#endif
+	/* for non-single file segments that aren't in-memory, we can close fd
+	 * here */
+	if (!internal_config.single_file_segments && !internal_config.in_memory)
+		close(fd);
+
+	ms->addr = addr;
+	ms->hugepage_sz = alloc_sz;
+	ms->len = alloc_sz;
+	ms->nchannel = rte_memory_get_nchannel();
+	ms->nrank = rte_memory_get_nrank();
+	ms->iova = iova;
+	ms->socket_id = socket_id;
+
+	return 0;
+
+mapped:
+	munmap(addr, alloc_sz);
+unmapped:
+	flags = MAP_FIXED;
+#ifdef RTE_ARCH_PPC_64
+	flags |= MAP_HUGETLB;
+#endif
+	new_addr = eal_get_virtual_area(addr, &alloc_sz, alloc_sz, 0, flags);
+	if (new_addr != addr) {
+		if (new_addr != NULL)
+			munmap(new_addr, alloc_sz);
+		/* we're leaving a hole in our virtual address space. if
+		 * somebody else maps this hole now, we could accidentally
+		 * override it in the future.
+		 */
+		RTE_LOG(CRIT, EAL, "Can't mmap holes in our virtual address space\n");
+	}
+resized:
+	/* in-memory mode will never be single-file-segments mode */
+	if (internal_config.single_file_segments) {
+		resize_hugefile(fd, path, list_idx, seg_idx, map_offset,
+				alloc_sz, false);
+		/* ignore failure, can't make it any worse */
+	} else {
+		/* only remove file if we can take out a write lock */
+		if (internal_config.hugepage_unlink == 0 &&
+				internal_config.in_memory == 0 &&
+				lock(fd, LOCK_EX) == 1)
+			unlink(path);
+		close(fd);
+	}
+	return -1;
+}
+
+static int
+free_seg(struct rte_memseg *ms, struct hugepage_info *hi,
+		unsigned int list_idx, unsigned int seg_idx)
+{
+	uint64_t map_offset;
+	char path[PATH_MAX];
+	int fd, ret;
+
+	/* erase page data */
+	memset(ms->addr, 0, ms->len);
+
+	if (mmap(ms->addr, ms->len, PROT_READ,
+			MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0) ==
+				MAP_FAILED) {
+		RTE_LOG(DEBUG, EAL, "couldn't unmap page\n");
+		return -1;
+	}
+
+	/* if we've already unlinked the page, nothing needs to be done */
+	if (internal_config.hugepage_unlink) {
+		memset(ms, 0, sizeof(*ms));
+		return 0;
+	}
+
+	/* if we are not in single file segments mode, we're going to unmap the
+	 * segment and thus drop the lock on original fd, but hugepage dir is
+	 * now locked so we can take out another one without races.
+	 */
+	fd = get_seg_fd(path, sizeof(path), hi, list_idx, seg_idx);
+	if (fd < 0)
+		return -1;
+
+	if (internal_config.single_file_segments) {
+		map_offset = seg_idx * ms->len;
+		if (resize_hugefile(fd, path, list_idx, seg_idx, map_offset,
+				ms->len, false))
+			return -1;
+		ret = 0;
+	} else {
+		/* if we're able to take out a write lock, we're the last one
+		 * holding onto this page.
+		 */
+		ret = lock(fd, LOCK_EX);
+		if (ret >= 0) {
+			/* no one else is using this page */
+			if (ret == 1)
+				unlink(path);
+		}
+		/* closing fd will drop the lock */
+		close(fd);
+	}
+
+	memset(ms, 0, sizeof(*ms));
+
+	return ret < 0 ? -1 : 0;
+}
+
+struct alloc_walk_param {
+	struct hugepage_info *hi;
+	struct rte_memseg **ms;
+	size_t page_sz;
+	unsigned int segs_allocated;
+	unsigned int n_segs;
+	int socket;
+	bool exact;
+};
+static int
+alloc_seg_walk(const struct rte_memseg_list *msl, void *arg)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	struct alloc_walk_param *wa = arg;
+	struct rte_memseg_list *cur_msl;
+	size_t page_sz;
+	int cur_idx, start_idx, j, dir_fd = -1;
+	unsigned int msl_idx, need, i;
+
+	if (msl->page_sz != wa->page_sz)
+		return 0;
+	if (msl->socket_id != wa->socket)
+		return 0;
+
+	page_sz = (size_t)msl->page_sz;
+
+	msl_idx = msl - mcfg->memsegs;
+	cur_msl = &mcfg->memsegs[msl_idx];
+
+	need = wa->n_segs;
+
+	/* try finding space in memseg list */
+	cur_idx = rte_fbarray_find_next_n_free(&cur_msl->memseg_arr, 0, need);
+	if (cur_idx < 0)
+		return 0;
+	start_idx = cur_idx;
+
+	/* do not allow any page allocations during the time we're allocating,
+	 * because file creation and locking operations are not atomic,
+	 * and we might be the first or the last ones to use a particular page,
+	 * so we need to ensure atomicity of every operation.
+	 *
+	 * during init, we already hold a write lock, so don't try to take out
+	 * another one.
+	 */
+	if (wa->hi->lock_descriptor == -1 && !internal_config.in_memory) {
+		dir_fd = open(wa->hi->hugedir, O_RDONLY);
+		if (dir_fd < 0) {
+			RTE_LOG(ERR, EAL, "%s(): Cannot open '%s': %s\n",
+				__func__, wa->hi->hugedir, strerror(errno));
+			return -1;
+		}
+		/* blocking writelock */
+		if (flock(dir_fd, LOCK_EX)) {
+			RTE_LOG(ERR, EAL, "%s(): Cannot lock '%s': %s\n",
+				__func__, wa->hi->hugedir, strerror(errno));
+			close(dir_fd);
+			return -1;
+		}
+	}
+
+	for (i = 0; i < need; i++, cur_idx++) {
+		struct rte_memseg *cur;
+		void *map_addr;
+
+		cur = rte_fbarray_get(&cur_msl->memseg_arr, cur_idx);
+		map_addr = RTE_PTR_ADD(cur_msl->base_va,
+				cur_idx * page_sz);
+
+		if (alloc_seg(cur, map_addr, wa->socket, wa->hi,
+				msl_idx, cur_idx)) {
+			RTE_LOG(DEBUG, EAL, "attempted to allocate %i segments, but only %i were allocated\n",
+				need, i);
+
+			/* if exact number wasn't requested, stop */
+			if (!wa->exact)
+				goto out;
+
+			/* clean up */
+			for (j = start_idx; j < cur_idx; j++) {
+				struct rte_memseg *tmp;
+				struct rte_fbarray *arr =
+						&cur_msl->memseg_arr;
+
+				tmp = rte_fbarray_get(arr, j);
+				rte_fbarray_set_free(arr, j);
+
+				/* free_seg may attempt to create a file, which
+				 * may fail.
+				 */
+				if (free_seg(tmp, wa->hi, msl_idx, j))
+					RTE_LOG(DEBUG, EAL, "Cannot free page\n");
+			}
+			/* clear the list */
+			if (wa->ms)
+				memset(wa->ms, 0, sizeof(*wa->ms) * wa->n_segs);
+
+			if (dir_fd >= 0)
+				close(dir_fd);
+			return -1;
+		}
+		if (wa->ms)
+			wa->ms[i] = cur;
+
+		rte_fbarray_set_used(&cur_msl->memseg_arr, cur_idx);
+	}
+out:
+	wa->segs_allocated = i;
+	if (i > 0)
+		cur_msl->version++;
+	if (dir_fd >= 0)
+		close(dir_fd);
+	return 1;
+}
+
+struct free_walk_param {
+	struct hugepage_info *hi;
+	struct rte_memseg *ms;
+};
+static int
+free_seg_walk(const struct rte_memseg_list *msl, void *arg)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	struct rte_memseg_list *found_msl;
+	struct free_walk_param *wa = arg;
+	uintptr_t start_addr, end_addr;
+	int msl_idx, seg_idx, ret, dir_fd = -1;
+
+	start_addr = (uintptr_t) msl->base_va;
+	end_addr = start_addr + msl->memseg_arr.len * (size_t)msl->page_sz;
+
+	if ((uintptr_t)wa->ms->addr < start_addr ||
+			(uintptr_t)wa->ms->addr >= end_addr)
+		return 0;
+
+	msl_idx = msl - mcfg->memsegs;
+	seg_idx = RTE_PTR_DIFF(wa->ms->addr, start_addr) / msl->page_sz;
+
+	/* msl is const */
+	found_msl = &mcfg->memsegs[msl_idx];
+
+	/* do not allow any page allocations during the time we're freeing,
+	 * because file creation and locking operations are not atomic,
+	 * and we might be the first or the last ones to use a particular page,
+	 * so we need to ensure atomicity of every operation.
+	 *
+	 * during init, we already hold a write lock, so don't try to take out
+	 * another one.
+	 */
+	if (wa->hi->lock_descriptor == -1 && !internal_config.in_memory) {
+		dir_fd = open(wa->hi->hugedir, O_RDONLY);
+		if (dir_fd < 0) {
+			RTE_LOG(ERR, EAL, "%s(): Cannot open '%s': %s\n",
+				__func__, wa->hi->hugedir, strerror(errno));
+			return -1;
+		}
+		/* blocking writelock */
+		if (flock(dir_fd, LOCK_EX)) {
+			RTE_LOG(ERR, EAL, "%s(): Cannot lock '%s': %s\n",
+				__func__, wa->hi->hugedir, strerror(errno));
+			close(dir_fd);
+			return -1;
+		}
+	}
+
+	found_msl->version++;
+
+	rte_fbarray_set_free(&found_msl->memseg_arr, seg_idx);
+
+	ret = free_seg(wa->ms, wa->hi, msl_idx, seg_idx);
+
+	if (dir_fd >= 0)
+		close(dir_fd);
+
+	if (ret < 0)
+		return -1;
+
+	return 1;
+}
+
+int
+eal_memalloc_alloc_seg_bulk(struct rte_memseg **ms, int n_segs, size_t page_sz,
+		int socket, bool exact)
+{
+	int i, ret = -1;
+#ifdef RTE_EAL_NUMA_AWARE_HUGEPAGES
+	bool have_numa = false;
+	int oldpolicy;
+	struct bitmask *oldmask;
+#endif
+	struct alloc_walk_param wa;
+	struct hugepage_info *hi = NULL;
+
+	memset(&wa, 0, sizeof(wa));
+
+	/* dynamic allocation not supported in legacy mode */
+	if (internal_config.legacy_mem)
+		return -1;
+
+	for (i = 0; i < (int) RTE_DIM(internal_config.hugepage_info); i++) {
+		if (page_sz ==
+				internal_config.hugepage_info[i].hugepage_sz) {
+			hi = &internal_config.hugepage_info[i];
+			break;
+		}
+	}
+	if (!hi) {
+		RTE_LOG(ERR, EAL, "%s(): can't find relevant hugepage_info entry\n",
+			__func__);
+		return -1;
+	}
+
+#ifdef RTE_EAL_NUMA_AWARE_HUGEPAGES
+	if (check_numa()) {
+		oldmask = numa_allocate_nodemask();
+		prepare_numa(&oldpolicy, oldmask, socket);
+		have_numa = true;
+	}
+#endif
+
+	wa.exact = exact;
+	wa.hi = hi;
+	wa.ms = ms;
+	wa.n_segs = n_segs;
+	wa.page_sz = page_sz;
+	wa.socket = socket;
+	wa.segs_allocated = 0;
+
+	/* memalloc is locked, so it's safe to use thread-unsafe version */
+	ret = rte_memseg_list_walk_thread_unsafe(alloc_seg_walk, &wa);
+	if (ret == 0) {
+		RTE_LOG(ERR, EAL, "%s(): couldn't find suitable memseg_list\n",
+			__func__);
+		ret = -1;
+	} else if (ret > 0) {
+		ret = (int)wa.segs_allocated;
+	}
+
+#ifdef RTE_EAL_NUMA_AWARE_HUGEPAGES
+	if (have_numa)
+		restore_numa(&oldpolicy, oldmask);
+#endif
+	return ret;
+}
+
+struct rte_memseg *
+eal_memalloc_alloc_seg(size_t page_sz, int socket)
+{
+	struct rte_memseg *ms;
+	if (eal_memalloc_alloc_seg_bulk(&ms, 1, page_sz, socket, true) < 0)
+		return NULL;
+	/* return pointer to newly allocated memseg */
+	return ms;
+}
+
+int
+eal_memalloc_free_seg_bulk(struct rte_memseg **ms, int n_segs)
+{
+	int seg, ret = 0;
+
+	/* dynamic free not supported in legacy mode */
+	if (internal_config.legacy_mem)
+		return -1;
+
+	for (seg = 0; seg < n_segs; seg++) {
+		struct rte_memseg *cur = ms[seg];
+		struct hugepage_info *hi = NULL;
+		struct free_walk_param wa;
+		int i, walk_res;
+
+		/* if this page is marked as unfreeable, fail */
+		if (cur->flags & RTE_MEMSEG_FLAG_DO_NOT_FREE) {
+			RTE_LOG(DEBUG, EAL, "Page is not allowed to be freed\n");
+			ret = -1;
+			continue;
+		}
+
+		memset(&wa, 0, sizeof(wa));
+
+		for (i = 0; i < (int)RTE_DIM(internal_config.hugepage_info);
+				i++) {
+			hi = &internal_config.hugepage_info[i];
+			if (cur->hugepage_sz == hi->hugepage_sz)
+				break;
+		}
+		if (i == (int)RTE_DIM(internal_config.hugepage_info)) {
+			RTE_LOG(ERR, EAL, "Can't find relevant hugepage_info entry\n");
+			ret = -1;
+			continue;
+		}
+
+		wa.ms = cur;
+		wa.hi = hi;
+
+		/* memalloc is locked, so it's safe to use thread-unsafe version
+		 */
+		walk_res = rte_memseg_list_walk_thread_unsafe(free_seg_walk,
+				&wa);
+		if (walk_res == 1)
+			continue;
+		if (walk_res == 0)
+			RTE_LOG(ERR, EAL, "Couldn't find memseg list\n");
+		ret = -1;
+	}
+	return ret;
+}
+
+int
+eal_memalloc_free_seg(struct rte_memseg *ms)
+{
+	/* dynamic free not supported in legacy mode */
+	if (internal_config.legacy_mem)
+		return -1;
+
+	return eal_memalloc_free_seg_bulk(&ms, 1);
+}
+
+static int
+sync_chunk(struct rte_memseg_list *primary_msl,
+		struct rte_memseg_list *local_msl, struct hugepage_info *hi,
+		unsigned int msl_idx, bool used, int start, int end)
+{
+	struct rte_fbarray *l_arr, *p_arr;
+	int i, ret, chunk_len, diff_len;
+
+	l_arr = &local_msl->memseg_arr;
+	p_arr = &primary_msl->memseg_arr;
+
+	/* we need to aggregate allocations/deallocations into bigger chunks,
+	 * as we don't want to spam the user with per-page callbacks.
+	 *
+	 * to avoid any potential issues, we also want to trigger
+	 * deallocation callbacks *before* we actually deallocate
+	 * memory, so that the user application could wrap up its use
+	 * before it goes away.
+	 */
+
+	chunk_len = end - start;
+
+	/* find how many contiguous pages we can map/unmap for this chunk */
+	diff_len = used ?
+			rte_fbarray_find_contig_free(l_arr, start) :
+			rte_fbarray_find_contig_used(l_arr, start);
+
+	/* has to be at least one page */
+	if (diff_len < 1)
+		return -1;
+
+	diff_len = RTE_MIN(chunk_len, diff_len);
+
+	/* if we are freeing memory, notify the application */
+	if (!used) {
+		struct rte_memseg *ms;
+		void *start_va;
+		size_t len, page_sz;
+
+		ms = rte_fbarray_get(l_arr, start);
+		start_va = ms->addr;
+		page_sz = (size_t)primary_msl->page_sz;
+		len = page_sz * diff_len;
+
+		eal_memalloc_mem_event_notify(RTE_MEM_EVENT_FREE,
+				start_va, len);
+	}
+
+	for (i = 0; i < diff_len; i++) {
+		struct rte_memseg *p_ms, *l_ms;
+		int seg_idx = start + i;
+
+		l_ms = rte_fbarray_get(l_arr, seg_idx);
+		p_ms = rte_fbarray_get(p_arr, seg_idx);
+
+		if (l_ms == NULL || p_ms == NULL)
+			return -1;
+
+		if (used) {
+			ret = alloc_seg(l_ms, p_ms->addr,
+					p_ms->socket_id, hi,
+					msl_idx, seg_idx);
+			if (ret < 0)
+				return -1;
+			rte_fbarray_set_used(l_arr, seg_idx);
+		} else {
+			ret = free_seg(l_ms, hi, msl_idx, seg_idx);
+			rte_fbarray_set_free(l_arr, seg_idx);
+			if (ret < 0)
+				return -1;
+		}
+	}
+
+	/* if we just allocated memory, notify the application */
+	if (used) {
+		struct rte_memseg *ms;
+		void *start_va;
+		size_t len, page_sz;
+
+		ms = rte_fbarray_get(l_arr, start);
+		start_va = ms->addr;
+		page_sz = (size_t)primary_msl->page_sz;
+		len = page_sz * diff_len;
+
+		eal_memalloc_mem_event_notify(RTE_MEM_EVENT_ALLOC,
+				start_va, len);
+	}
+
+	/* calculate how much we can advance until next chunk */
+	diff_len = used ?
+			rte_fbarray_find_contig_used(l_arr, start) :
+			rte_fbarray_find_contig_free(l_arr, start);
+	ret = RTE_MIN(chunk_len, diff_len);
+
+	return ret;
+}
+
+static int
+sync_status(struct rte_memseg_list *primary_msl,
+		struct rte_memseg_list *local_msl, struct hugepage_info *hi,
+		unsigned int msl_idx, bool used)
+{
+	struct rte_fbarray *l_arr, *p_arr;
+	int p_idx, l_chunk_len, p_chunk_len, ret;
+	int start, end;
+
+	/* this is a little bit tricky, but the basic idea is - walk both lists
+	 * and spot any places where there are discrepancies. walking both lists
+	 * and noting discrepancies in a single go is a hard problem, so we do
+	 * it in two passes - first we spot any places where allocated segments
+	 * mismatch (i.e. ensure that everything that's allocated in the primary
+	 * is also allocated in the secondary), and then we do it by looking at
+	 * free segments instead.
+	 *
+	 * we also need to aggregate changes into chunks, as we have to call
+	 * callbacks per allocation, not per page.
+	 */
+	l_arr = &local_msl->memseg_arr;
+	p_arr = &primary_msl->memseg_arr;
+
+	if (used)
+		p_idx = rte_fbarray_find_next_used(p_arr, 0);
+	else
+		p_idx = rte_fbarray_find_next_free(p_arr, 0);
+
+	while (p_idx >= 0) {
+		int next_chunk_search_idx;
+
+		if (used) {
+			p_chunk_len = rte_fbarray_find_contig_used(p_arr,
+					p_idx);
+			l_chunk_len = rte_fbarray_find_contig_used(l_arr,
+					p_idx);
+		} else {
+			p_chunk_len = rte_fbarray_find_contig_free(p_arr,
+					p_idx);
+			l_chunk_len = rte_fbarray_find_contig_free(l_arr,
+					p_idx);
+		}
+		/* best case scenario - no differences (or bigger, which will be
+		 * fixed during next iteration), look for next chunk
+		 */
+		if (l_chunk_len >= p_chunk_len) {
+			next_chunk_search_idx = p_idx + p_chunk_len;
+			goto next_chunk;
+		}
+
+		/* if both chunks start at the same point, skip parts we know
+		 * are identical, and sync the rest. each call to sync_chunk
+		 * will only sync contiguous segments, so we need to call this
+		 * until we are sure there are no more differences in this
+		 * chunk.
+		 */
+		start = p_idx + l_chunk_len;
+		end = p_idx + p_chunk_len;
+		do {
+			ret = sync_chunk(primary_msl, local_msl, hi, msl_idx,
+					used, start, end);
+			start += ret;
+		} while (start < end && ret >= 0);
+		/* if ret is negative, something went wrong */
+		if (ret < 0)
+			return -1;
+
+		next_chunk_search_idx = p_idx + p_chunk_len;
+next_chunk:
+		/* skip to end of this chunk */
+		if (used) {
+			p_idx = rte_fbarray_find_next_used(p_arr,
+					next_chunk_search_idx);
+		} else {
+			p_idx = rte_fbarray_find_next_free(p_arr,
+					next_chunk_search_idx);
+		}
+	}
+	return 0;
+}
+
+static int
+sync_existing(struct rte_memseg_list *primary_msl,
+		struct rte_memseg_list *local_msl, struct hugepage_info *hi,
+		unsigned int msl_idx)
+{
+	int ret, dir_fd;
+
+	/* do not allow any page allocations during the time we're allocating,
+	 * because file creation and locking operations are not atomic,
+	 * and we might be the first or the last ones to use a particular page,
+	 * so we need to ensure atomicity of every operation.
+	 */
+	dir_fd = open(hi->hugedir, O_RDONLY);
+	if (dir_fd < 0) {
+		RTE_LOG(ERR, EAL, "%s(): Cannot open '%s': %s\n", __func__,
+			hi->hugedir, strerror(errno));
+		return -1;
+	}
+	/* blocking writelock */
+	if (flock(dir_fd, LOCK_EX)) {
+		RTE_LOG(ERR, EAL, "%s(): Cannot lock '%s': %s\n", __func__,
+			hi->hugedir, strerror(errno));
+		close(dir_fd);
+		return -1;
+	}
+
+	/* ensure all allocated space is the same in both lists */
+	ret = sync_status(primary_msl, local_msl, hi, msl_idx, true);
+	if (ret < 0)
+		goto fail;
+
+	/* ensure all unallocated space is the same in both lists */
+	ret = sync_status(primary_msl, local_msl, hi, msl_idx, false);
+	if (ret < 0)
+		goto fail;
+
+	/* update version number */
+	local_msl->version = primary_msl->version;
+
+	close(dir_fd);
+
+	return 0;
+fail:
+	close(dir_fd);
+	return -1;
+}
+
+static int
+sync_walk(const struct rte_memseg_list *msl, void *arg __rte_unused)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	struct rte_memseg_list *primary_msl, *local_msl;
+	struct hugepage_info *hi = NULL;
+	unsigned int i;
+	int msl_idx;
+
+	msl_idx = msl - mcfg->memsegs;
+	primary_msl = &mcfg->memsegs[msl_idx];
+	local_msl = &local_memsegs[msl_idx];
+
+	for (i = 0; i < RTE_DIM(internal_config.hugepage_info); i++) {
+		uint64_t cur_sz =
+			internal_config.hugepage_info[i].hugepage_sz;
+		uint64_t msl_sz = primary_msl->page_sz;
+		if (msl_sz == cur_sz) {
+			hi = &internal_config.hugepage_info[i];
+			break;
+		}
+	}
+	if (!hi) {
+		RTE_LOG(ERR, EAL, "Can't find relevant hugepage_info entry\n");
+		return -1;
+	}
+
+	/* if versions don't match, synchronize everything */
+	if (local_msl->version != primary_msl->version &&
+			sync_existing(primary_msl, local_msl, hi, msl_idx))
+		return -1;
+	return 0;
+}
+
+
+int
+eal_memalloc_sync_with_primary(void)
+{
+	/* nothing to be done in primary */
+	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
+		return 0;
+
+	/* memalloc is locked, so it's safe to call thread-unsafe version */
+	if (rte_memseg_list_walk_thread_unsafe(sync_walk, NULL))
+		return -1;
+	return 0;
+}
+
+static int
+secondary_msl_create_walk(const struct rte_memseg_list *msl,
+		void *arg __rte_unused)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	struct rte_memseg_list *primary_msl, *local_msl;
+	char name[PATH_MAX];
+	int msl_idx, ret;
+
+	msl_idx = msl - mcfg->memsegs;
+	primary_msl = &mcfg->memsegs[msl_idx];
+	local_msl = &local_memsegs[msl_idx];
+
+	/* create distinct fbarrays for each secondary */
+	snprintf(name, RTE_FBARRAY_NAME_LEN, "%s_%i",
+		primary_msl->memseg_arr.name, getpid());
+
+	ret = rte_fbarray_init(&local_msl->memseg_arr, name,
+		primary_msl->memseg_arr.len,
+		primary_msl->memseg_arr.elt_sz);
+	if (ret < 0) {
+		RTE_LOG(ERR, EAL, "Cannot initialize local memory map\n");
+		return -1;
+	}
+	local_msl->base_va = primary_msl->base_va;
+
+	return 0;
+}
+
+static int
+secondary_lock_list_create_walk(const struct rte_memseg_list *msl,
+		void *arg __rte_unused)
+{
+	struct rte_mem_config *mcfg = rte_eal_get_configuration()->mem_config;
+	unsigned int i, len;
+	int msl_idx;
+	int *data;
+
+	msl_idx = msl - mcfg->memsegs;
+	len = msl->memseg_arr.len;
+
+	/* ensure we have space to store lock fd per each possible segment */
+	data = malloc(sizeof(int) * len);
+	if (data == NULL) {
+		RTE_LOG(ERR, EAL, "Unable to allocate space for lock descriptors\n");
+		return -1;
+	}
+	/* set all fd's as invalid */
+	for (i = 0; i < len; i++)
+		data[i] = -1;
+
+	lock_fds[msl_idx].fds = data;
+	lock_fds[msl_idx].len = len;
+	lock_fds[msl_idx].count = 0;
+	lock_fds[msl_idx].memseg_list_fd = -1;
+
+	return 0;
+}
+
+int
+eal_memalloc_init(void)
+{
+	if (rte_eal_process_type() == RTE_PROC_SECONDARY)
+		if (rte_memseg_list_walk(secondary_msl_create_walk, NULL) < 0)
+			return -1;
+
+	/* initialize all of the lock fd lists */
+	if (internal_config.single_file_segments)
+		if (rte_memseg_list_walk(secondary_lock_list_create_walk, NULL))
+			return -1;
+	return 0;
+}