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[ceph.git] / ceph / src / spdk / dpdk / lib / librte_eal / linuxapp / eal / eal_memalloc.c

/* 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;
}