diff options
Diffstat (limited to 'svm/svm.c')
| -rw-r--r-- | svm/svm.c | 1045 |
1 files changed, 1045 insertions, 0 deletions
diff --git a/svm/svm.c b/svm/svm.c new file mode 100644 index 00000000000..c629f932008 --- /dev/null +++ b/svm/svm.c @@ -0,0 +1,1045 @@ +/* + *------------------------------------------------------------------ + * svm.c - shared VM allocation, mmap(...MAP_FIXED...) + * library + * + * Copyright (c) 2009 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + *------------------------------------------------------------------ + */ + +#include <stdio.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <netinet/in.h> +#include <signal.h> +#include <pthread.h> +#include <unistd.h> +#include <time.h> +#include <fcntl.h> +#include <string.h> +#include <vppinfra/clib.h> +#include <vppinfra/vec.h> +#include <vppinfra/hash.h> +#include <vppinfra/bitmap.h> +#include <vppinfra/fifo.h> +#include <vppinfra/time.h> +#include <vppinfra/mheap.h> +#include <vppinfra/heap.h> +#include <vppinfra/pool.h> +#include <vppinfra/format.h> + +#include "svm.h" + +static svm_region_t *root_rp; +static int root_rp_refcount; + +#define MAXLOCK 2 +static pthread_mutex_t *mutexes_held [MAXLOCK]; +static int nheld; + +svm_region_t *svm_get_root_rp (void) +{ + return root_rp; +} + +#define MUTEX_DEBUG + +static void region_lock(svm_region_t *rp, int tag) +{ + pthread_mutex_lock(&rp->mutex); +#ifdef MUTEX_DEBUG + rp->mutex_owner_pid = getpid(); + rp->mutex_owner_tag = tag; +#endif + ASSERT(nheld < MAXLOCK); + /* + * Keep score of held mutexes so we can try to exit + * cleanly if the world comes to an end at the worst possible + * moment + */ + mutexes_held [nheld++] = &rp->mutex; +} + +static void region_unlock(svm_region_t *rp) +{ + int i,j; +#ifdef MUTEX_DEBUG + rp->mutex_owner_pid = 0; + rp->mutex_owner_tag = 0; +#endif + + for (i = nheld-1; i >= 0; i--) { + if (mutexes_held[i] == &rp->mutex) { + for (j = i; j < MAXLOCK-1; j++) + mutexes_held[j] = mutexes_held[j+1]; + nheld--; + goto found; + } + } + ASSERT(0); + +found: + CLIB_MEMORY_BARRIER(); + pthread_mutex_unlock(&rp->mutex); +} + + +static u8 * format_svm_flags (u8 * s, va_list * args) +{ + uword f = va_arg (*args, uword); + + if (f & SVM_FLAGS_MHEAP) + s = format (s, "MHEAP "); + if (f & SVM_FLAGS_FILE) + s = format (s, "FILE "); + if (f & SVM_FLAGS_NODATA) + s = format (s, "NODATA "); + if (f & SVM_FLAGS_NEED_DATA_INIT) + s = format (s, "INIT "); + + return (s); +} + +static u8 * format_svm_size (u8 * s, va_list * args) +{ + uword size = va_arg (*args, uword); + + if (size >= (1>>20)) { + s = format (s, "(%d mb)", size >> 20); + } else if (size >= (1>>10)) { + s = format (s, "(%d kb)", size >> 10); + } else { + s = format (s, "(%d bytes)", size); + } + return (s); +} + +u8 * format_svm_region (u8 * s, va_list * args) +{ + svm_region_t *rp = va_arg (*args, svm_region_t *); + int verbose = va_arg (*args, int); + int i; + uword lo, hi; + + s = format (s, "%s: base va 0x%x size 0x%x %U\n", + rp->region_name, rp->virtual_base, + rp->virtual_size, format_svm_size, rp->virtual_size); + s = format (s, " user_ctx 0x%x, bitmap_size %d\n", + rp->user_ctx, rp->bitmap_size); + + if (verbose) { + s = format (s, " flags: 0x%x %U\n", rp->flags, + format_svm_flags, rp->flags); + s = format (s, + " region_heap 0x%x data_base 0x%x data_heap 0x%x\n", + rp->region_heap, rp->data_base, rp->data_heap); + } + + s = format (s, " %d clients, pids: ", + vec_len(rp->client_pids)); + + for (i = 0; i < vec_len(rp->client_pids); i++) + s = format (s, "%d ", rp->client_pids[i]); + + s = format (s, "\n"); + + if (verbose) { + lo = hi = ~0; + + s = format (s, " VM in use: "); + + for (i = 0; i < rp->bitmap_size; i++) { + if (clib_bitmap_get_no_check (rp->bitmap, i) != 0) { + if (lo == ~0) { + hi = lo = rp->virtual_base + i*MMAP_PAGESIZE; + } else { + hi = rp->virtual_base + i*MMAP_PAGESIZE; + } + } else { + if (lo != ~0) { + hi = rp->virtual_base + i*MMAP_PAGESIZE -1; + s = format (s, " 0x%x - 0x%x (%dk)\n", lo, hi, + (hi - lo)>>10); + lo = hi = ~0; + } + } + } + s = format (s, " rgn heap stats: %U", format_mheap, + rp->region_heap, 0); + if ((rp->flags & SVM_FLAGS_MHEAP) && rp->data_heap) { + s = format (s, "\n data heap stats: %U", format_mheap, + rp->data_heap, 1); + } + s = format (s, "\n"); + } + + return(s); +} + +/* + * rnd_pagesize + * Round to a pagesize multiple, presumably 4k works + */ +static unsigned int rnd_pagesize(unsigned int size) +{ + unsigned int rv; + + rv = (size + (MMAP_PAGESIZE-1)) & ~(MMAP_PAGESIZE-1); + return(rv); +} + +/* + * svm_data_region_setup + */ +static int svm_data_region_create (svm_map_region_args_t *a, + svm_region_t *rp) +{ + int fd; + u8 junk = 0; + uword map_size; + + map_size = rp->virtual_size - (MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE); + + if (a->flags & SVM_FLAGS_FILE) { + struct stat statb; + + fd = open (a->backing_file, O_RDWR | O_CREAT, 0777); + + if (fd < 0) { + clib_unix_warning ("open"); + return -1; + } + + if (fstat(fd, &statb) < 0) { + clib_unix_warning("fstat"); + return -2; + } + + if (statb.st_mode & S_IFREG) { + if (statb.st_size == 0) { + lseek(fd, map_size, SEEK_SET); + if (write(fd, &junk, 1) != 1) + clib_unix_warning ("set region size"); + } else { + map_size = rnd_pagesize (statb.st_size); + } + } else { + map_size = a->backing_mmap_size; + } + + ASSERT(map_size <= rp->virtual_size - + (MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE)); + + if (mmap (rp->data_base, map_size, PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_FIXED, fd, 0) == MAP_FAILED) { + clib_unix_warning("mmap"); + return -3; + } + close(fd); + rp->backing_file = (char *) format(0, "%s\0", a->backing_file); + rp->flags |= SVM_FLAGS_FILE; + } + + if (a->flags & SVM_FLAGS_MHEAP) { + rp->data_heap = + mheap_alloc_with_flags ((void *)(rp->data_base), map_size, + MHEAP_FLAG_DISABLE_VM); + rp->flags |= SVM_FLAGS_MHEAP; + } + return 0; +} + +static int svm_data_region_map (svm_map_region_args_t *a, + svm_region_t *rp) +{ + int fd; + u8 junk = 0; + uword map_size; + struct stat statb; + + map_size = rp->virtual_size - (MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE); + + if (a->flags & SVM_FLAGS_FILE) { + + fd = open (a->backing_file, O_RDWR, 0777); + + if (fd < 0) { + clib_unix_warning ("open"); + return -1; + } + + if (fstat(fd, &statb) < 0) { + clib_unix_warning("fstat"); + return -2; + } + + if (statb.st_mode & S_IFREG) { + if (statb.st_size == 0) { + lseek(fd, map_size, SEEK_SET); + if (write(fd, &junk, 1) != 1) + clib_unix_warning ("set region size"); + } else { + map_size = rnd_pagesize (statb.st_size); + } + } else { + map_size = a->backing_mmap_size; + } + + ASSERT(map_size <= rp->virtual_size + - (MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE)); + + if (mmap (rp->data_base, map_size, PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_FIXED, fd, 0) == MAP_FAILED) { + clib_unix_warning("mmap"); + return -3; + } + close(fd); + } + return 0; +} + +u8 *shm_name_from_svm_map_region_args (svm_map_region_args_t *a) +{ + u8 *path; + u8 *shm_name; + u8 *split_point; + u8 *mkdir_arg = 0; + int root_path_offset = 0; + int name_offset = 0; + + if (a->root_path) { + /* Tolerate present or absent slashes */ + if (a->root_path[0] == '/') + root_path_offset++; + + /* create the root_path under /dev/shm + iterate through path creating directories */ + + path = format (0, "/dev/shm/%s%c", &a->root_path[root_path_offset], 0); + split_point = path+1; + vec_add1(mkdir_arg, '-'); + + while (*split_point) { + while (*split_point && *split_point != '/') { + vec_add1 (mkdir_arg, *split_point); + split_point++; + } + vec_add1 (mkdir_arg, 0); + if (mkdir ((char *) mkdir_arg, 0777) < 0 && errno != EEXIST) + clib_unix_warning ("mkdir %s", mkdir_arg); + + /* ready to descend another level */ + mkdir_arg[vec_len(mkdir_arg)-1] = '-'; + split_point++; + } + vec_free(mkdir_arg); + vec_free(path); + + if (a->name[0] == '/') + name_offset = 1; + + shm_name = format (0, "/%s-%s%c", a->root_path, + &a->name[name_offset], 0); + } + else + shm_name = format (0, "%s%c", a->name, 0); + return (shm_name); +} + +/* + * svm_map_region + */ +void *svm_map_region (svm_map_region_args_t *a) +{ + int svm_fd; + svm_region_t *rp; + pthread_mutexattr_t attr; + pthread_condattr_t cattr; + int deadman=0; + u8 junk = 0; + void *oldheap; + int overhead_space; + int rv; + uword data_base; + int nbits, words, bit; + int pid_holding_region_lock; + u8 *shm_name; + int dead_region_recovery = 0; + int time_left; + struct stat stat; + struct timespec ts, tsrem; + + if (CLIB_DEBUG > 1) + clib_warning ("[%d] map region %s", getpid(), a->name); + + ASSERT((a->size & ~(MMAP_PAGESIZE-1)) == a->size); + ASSERT(a->name); + + shm_name = shm_name_from_svm_map_region_args (a); + + svm_fd = shm_open((char *) shm_name, O_RDWR | O_CREAT | O_EXCL, 0777); + + if (svm_fd >= 0) { + + vec_free(shm_name); + + lseek(svm_fd, a->size, SEEK_SET); + if (write(svm_fd, &junk, 1) != 1) + clib_warning ("set region size"); + + rp = mmap((void *)a->baseva, a->size, + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, svm_fd, 0); + + if (rp == (svm_region_t *) MAP_FAILED) { + clib_unix_warning ("mmap create"); + return (0); + } + close(svm_fd); + memset(rp, 0, sizeof(*rp)); + + if (pthread_mutexattr_init(&attr)) + clib_unix_warning("mutexattr_init"); + + if (pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED)) + clib_unix_warning("mutexattr_setpshared"); + + if (pthread_mutex_init(&rp->mutex, &attr)) + clib_unix_warning("mutex_init"); + + if (pthread_mutexattr_destroy(&attr)) + clib_unix_warning("mutexattr_destroy"); + + if (pthread_condattr_init(&cattr)) + clib_unix_warning("condattr_init"); + + if (pthread_condattr_setpshared(&cattr, PTHREAD_PROCESS_SHARED)) + clib_unix_warning("condattr_setpshared"); + + if (pthread_cond_init(&rp->condvar, &cattr)) + clib_unix_warning("cond_init"); + + if(pthread_condattr_destroy(&cattr)) + clib_unix_warning("condattr_destroy"); + + region_lock (rp, 1); + + rp->virtual_base = a->baseva; + rp->virtual_size = a->size; + + rp->region_heap = + mheap_alloc_with_flags ((void *)(a->baseva+MMAP_PAGESIZE), + SVM_PVT_MHEAP_SIZE, + MHEAP_FLAG_DISABLE_VM); + oldheap = svm_push_pvt_heap(rp); + + rp->region_name = (char *)format (0, "%s%c", a->name, 0); + vec_add1(rp->client_pids, getpid()); + + nbits = rp->virtual_size / MMAP_PAGESIZE; + + ASSERT (nbits > 0); + rp->bitmap_size = nbits; + words = (nbits + BITS(uword)-1) / BITS(uword); + vec_validate (rp->bitmap, words-1); + + overhead_space = MMAP_PAGESIZE /* header */ + + SVM_PVT_MHEAP_SIZE; + + bit = 0; + data_base = (uword)rp->virtual_base; + + if (a->flags & SVM_FLAGS_NODATA) + rp->flags |= SVM_FLAGS_NEED_DATA_INIT; + + do { + clib_bitmap_set_no_check (rp->bitmap, bit, 1); + bit++; + overhead_space -= MMAP_PAGESIZE; + data_base += MMAP_PAGESIZE; + } while (overhead_space > 0); + + rp->data_base = (void *)data_base; + + /* + * Note: although the POSIX spec guarantees that only one + * process enters this block, we have to play games + * to hold off clients until e.g. the mutex is ready + */ + rp->version = SVM_VERSION; + + /* setup the data portion of the region */ + + rv = svm_data_region_create (a, rp); + if (rv) { + clib_warning ("data_region_create: %d", rv); + } + + region_unlock(rp); + + svm_pop_heap(oldheap); + + return ((void *) rp); + } else { + svm_fd = shm_open((char *)shm_name, O_RDWR, 0777); + + vec_free(shm_name); + + if (svm_fd < 0) { + perror("svm_region_map(mmap open)"); + return (0); + } + + time_left = 20; + while (1) { + if (0 != fstat(svm_fd, &stat)) { + clib_warning("fstat failed: %d", errno); + return (0); + } + if (stat.st_size > 0) { + break; + } + if (0 == time_left) { + clib_warning("waiting for resize of shm file timed out"); + return (0); + } + ts.tv_sec = 0; + ts.tv_nsec = 100000000; + while (nanosleep(&ts, &tsrem) < 0) + ts = tsrem; + time_left--; + } + + rp = mmap(0, MMAP_PAGESIZE, + PROT_READ | PROT_WRITE, MAP_SHARED, svm_fd, 0); + + if (rp == (svm_region_t *) MAP_FAILED) { + close(svm_fd); + clib_warning("mmap"); + return (0); + } + /* + * We lost the footrace to create this region; make sure + * the winner has crossed the finish line. + */ + while (rp->version == 0 && deadman++ < 5) { + sleep(1); + } + + /* + * <bleep>-ed? + */ + if (rp->version == 0) { + close(svm_fd); + munmap(rp, a->size); + clib_warning("rp->version %d not %d", rp->version, + SVM_VERSION); + return (0); + } + /* Remap now that the region has been placed */ + a->baseva = rp->virtual_base; + a->size = rp->virtual_size; + munmap(rp, MMAP_PAGESIZE); + + rp = (void *) mmap ((void *)a->baseva, a->size, + PROT_READ | PROT_WRITE, + MAP_SHARED | MAP_FIXED, svm_fd, 0); + if ((uword)rp == (uword)MAP_FAILED) { + clib_unix_warning ("mmap"); + return (0); + } + + if ((uword) rp != rp->virtual_base) { + clib_warning("mmap botch"); + } + + /* + * Try to fix the region mutex if it is held by + * a dead process + */ + pid_holding_region_lock = rp->mutex_owner_pid; + if (pid_holding_region_lock && + kill (pid_holding_region_lock, 0) < 0) { + clib_warning ( + "region %s mutex held by dead pid %d, tag %d, force unlock", + rp->region_name, pid_holding_region_lock, rp->mutex_owner_tag); + /* owner pid is nonexistent */ + rp->mutex.__data.__owner = 0; + rp->mutex.__data.__lock = 0; + dead_region_recovery = 1; + } + + if (dead_region_recovery) + clib_warning ("recovery: attempt to re-lock region"); + + region_lock(rp, 2); + oldheap = svm_push_pvt_heap (rp); + vec_add1(rp->client_pids, getpid()); + + if (dead_region_recovery) + clib_warning ("recovery: attempt svm_data_region_map"); + + rv = svm_data_region_map (a, rp); + if (rv) { + clib_warning ("data_region_map: %d", rv); + } + + if (dead_region_recovery) + clib_warning ("unlock and continue"); + + region_unlock(rp); + + svm_pop_heap(oldheap); + + return ((void *) rp); + + } + return 0; /* NOTREACHED */ +} + +static void svm_mutex_cleanup (void) +{ + int i; + for (i = 0; i < nheld; i++) { + pthread_mutex_unlock (mutexes_held[i]); + } +} + +static void svm_region_init_internal (char *root_path) +{ + svm_region_t *rp; + svm_map_region_args_t *a=0; + u64 ticks = clib_cpu_time_now(); + uword randomize_baseva; + + /* guard against klutz calls */ + root_rp_refcount++; + if (root_rp) + return; + + atexit(svm_mutex_cleanup); + + /* Randomize the shared-VM base at init time */ + randomize_baseva = (ticks & 15) * 4096; + + vec_validate(a,0); + a->root_path = root_path; + a->name = SVM_GLOBAL_REGION_NAME; + a->baseva = SVM_GLOBAL_REGION_BASEVA + randomize_baseva; + a->size = SVM_GLOBAL_REGION_SIZE; + a->flags = SVM_FLAGS_NODATA; + + rp = svm_map_region (a); + ASSERT(rp); + + region_lock(rp, 3); + + /* Set up the main region data structures */ + if (rp->flags & SVM_FLAGS_NEED_DATA_INIT) { + svm_main_region_t *mp = 0; + void *oldheap; + + rp->flags &= ~(SVM_FLAGS_NEED_DATA_INIT); + + oldheap = svm_push_pvt_heap (rp); + vec_validate (mp, 0); + mp->name_hash = hash_create_string (0, sizeof(uword)); + mp->root_path = root_path + ? format (0, "%s%c", root_path, 0) : 0 ; + rp->data_base = mp; + svm_pop_heap (oldheap); + } + region_unlock(rp); + vec_free (a); + root_rp = rp; +} + +void svm_region_init (void) +{ + svm_region_init_internal (0); +} + +void svm_region_init_chroot (char *root_path) +{ + svm_region_init_internal (root_path); +} + +void *svm_region_find_or_create (svm_map_region_args_t *a) +{ + svm_main_region_t *mp; + svm_region_t *rp; + uword need_nbits; + int index, i; + void *oldheap; + uword *p; + u8 *name; + svm_subregion_t *subp; + + ASSERT(root_rp); + + a->size += MMAP_PAGESIZE + SVM_PVT_MHEAP_SIZE; + a->size = rnd_pagesize(a->size); + + region_lock (root_rp, 4); + oldheap = svm_push_pvt_heap(root_rp); + mp = root_rp->data_base; + + ASSERT(mp); + + /* Map the named region from the correct chroot environment */ + a->root_path = (char *) mp->root_path; + + /* + * See if this region is already known. If it is, we're + * almost done... + */ + p = hash_get_mem (mp->name_hash, a->name); + + if (p) { + rp = svm_map_region (a); + region_unlock(root_rp); + svm_pop_heap (oldheap); + return rp; + } + + /* Create the region. */ + ASSERT((a->size & ~(MMAP_PAGESIZE-1)) == a->size); + + need_nbits = a->size / MMAP_PAGESIZE; + + index = 1; /* $$$ fixme, figure out how many bit to really skip */ + + /* + * Scan the virtual space allocation bitmap, looking for a large + * enough chunk + */ + do { + if (clib_bitmap_get_no_check(root_rp->bitmap, index) == 0) { + for (i = 0; i < (need_nbits-1); i++) { + if (clib_bitmap_get_no_check(root_rp->bitmap, + index+i) == 1) { + index = index + i; + goto next; + } + } + break; + } + index++; + next:; + } while (index < root_rp->bitmap_size); + + /* Completely out of VM? */ + if (index >= root_rp->bitmap_size) { + clib_warning("region %s: not enough VM to allocate 0x%x", + root_rp->region_name, a->size); + svm_pop_heap (oldheap); + region_unlock (root_rp); + return 0; + } + + /* + * Mark virtual space allocated + */ +#if CLIB_DEBUG > 1 + clib_warning ("set %d bits at index %d", need_nbits, index); +#endif + + for (i = 0; i < need_nbits; i++) { + clib_bitmap_set_no_check (root_rp->bitmap, index+i, 1); + } + + /* Place this region where it goes... */ + a->baseva = root_rp->virtual_base + index*MMAP_PAGESIZE; + + rp = svm_map_region (a); + + pool_get (mp->subregions, subp); + name = format (0, "%s%c", a->name, 0); + subp->subregion_name = name; + + hash_set_mem (mp->name_hash, name, subp - mp->subregions); + + svm_pop_heap (oldheap); + + region_unlock (root_rp); + + return (rp); +} + +/* + * svm_region_unmap + * + * Let go of the indicated region. If the calling process + * is the last customer, throw it away completely. + * The root region mutex guarantees atomicity with respect to + * a new region client showing up at the wrong moment. + */ +void svm_region_unmap (void *rp_arg) +{ + int i, mypid = getpid(); + int nclients_left; + void *oldheap; + uword virtual_base, virtual_size; + svm_region_t *rp = rp_arg; + char *name; + + /* + * If we take a signal while holding one or more shared-memory + * mutexes, we may end up back here from an otherwise + * benign exit handler. Bail out to avoid a recursive + * mutex screw-up. + */ + if (nheld) + return; + + ASSERT(rp); + ASSERT(root_rp); + + if (CLIB_DEBUG > 1) + clib_warning ("[%d] unmap region %s", getpid(), rp->region_name); + + region_lock (root_rp, 5); + region_lock (rp, 6); + + oldheap = svm_push_pvt_heap (rp); /* nb vec_delete() in the loop */ + + /* Remove the caller from the list of mappers */ + for (i = 0; i < vec_len(rp->client_pids); i++) { + if (rp->client_pids[i] == mypid) { + vec_delete (rp->client_pids, 1, i); + goto found; + } + } + clib_warning("pid %d AWOL", mypid); + + found: + + svm_pop_heap (oldheap); + + nclients_left = vec_len(rp->client_pids); + virtual_base = rp->virtual_base; + virtual_size = rp->virtual_size; + + if (nclients_left == 0) { + int index, nbits, i; + svm_main_region_t *mp; + uword *p; + svm_subregion_t *subp; + + /* Kill the region, last guy on his way out */ + + oldheap = svm_push_pvt_heap (root_rp); + name = vec_dup (rp->region_name); + + virtual_base = rp->virtual_base; + virtual_size = rp->virtual_size; + + /* Figure out which bits to clear in the root region bitmap */ + index = (virtual_base - root_rp->virtual_base) + / MMAP_PAGESIZE; + + nbits = (virtual_size + MMAP_PAGESIZE - 1) + / MMAP_PAGESIZE; + +#if CLIB_DEBUG > 1 + clib_warning ("clear %d bits at index %d", nbits, index); +#endif + /* Give back the allocated VM */ + for (i = 0; i < nbits; i++) { + clib_bitmap_set_no_check (root_rp->bitmap, index+i, 0); + } + + mp = root_rp->data_base; + + p = hash_get_mem (mp->name_hash, name); + + /* Better never happen ... */ + if (p == NULL) { + region_unlock (rp); + region_unlock (root_rp); + svm_pop_heap (oldheap); + clib_warning ("Region name '%s' not found?", name); + return; + } + + /* Remove from the root region subregion pool */ + subp = mp->subregions + p[0]; + pool_put (mp->subregions, subp); + + hash_unset_mem (mp->name_hash, name); + + vec_free(name); + + region_unlock (rp); + shm_unlink(rp->region_name); + munmap ((void *)virtual_base, virtual_size); + region_unlock (root_rp); + svm_pop_heap (oldheap); + return; + } + + region_unlock(rp); + region_unlock(root_rp); + + munmap ((void *)virtual_base, virtual_size); +} + +/* + * svm_region_exit + * There is no clean way to unlink the + * root region when all clients go away, + * so remove the pid entry and call it a day. + */ +void svm_region_exit () +{ + void *oldheap; + int i, mypid = getpid(); + uword virtual_base, virtual_size; + + /* It felt so nice we did it twice... */ + if (root_rp == 0) + return; + + if (--root_rp_refcount > 0) + return; + + /* + * If we take a signal while holding one or more shared-memory + * mutexes, we may end up back here from an otherwise + * benign exit handler. Bail out to avoid a recursive + * mutex screw-up. + */ + if (nheld) + return; + + region_lock(root_rp, 7); + oldheap = svm_push_pvt_heap (root_rp); + + virtual_base = root_rp->virtual_base; + virtual_size = root_rp->virtual_size; + + for (i = 0; i < vec_len(root_rp->client_pids); i++) { + if (root_rp->client_pids[i] == mypid) { + vec_delete (root_rp->client_pids, 1, i); + goto found; + } + } + clib_warning("pid %d AWOL", mypid); + + found: + + region_unlock(root_rp); + svm_pop_heap (oldheap); + + root_rp = 0; + munmap ((void *)virtual_base, virtual_size); +} + +void svm_client_scan_this_region_nolock (svm_region_t *rp) +{ + int j; + int mypid = getpid(); + void *oldheap; + + for (j = 0; j < vec_len(rp->client_pids); j++) { + if (mypid == rp->client_pids[j]) + continue; + if (rp->client_pids[j] && (kill (rp->client_pids[j], 0) < 0)) { + clib_warning ("%s: cleanup ghost pid %d", + rp->region_name, rp->client_pids[j]); + /* nb: client vec in rp->region_heap */ + oldheap = svm_push_pvt_heap (rp); + vec_delete (rp->client_pids, 1, j); + j--; + svm_pop_heap (oldheap); + } + } +} + + +/* + * Scan svm regions for dead clients + */ +void svm_client_scan(char *root_path) +{ + int i, j; + svm_main_region_t *mp; + svm_map_region_args_t *a = 0; + svm_region_t *root_rp; + svm_region_t *rp; + svm_subregion_t *subp; + u8 *name=0; + u8 ** svm_names=0; + void *oldheap; + int mypid = getpid(); + + vec_validate (a, 0); + + svm_region_init_chroot(root_path); + + root_rp = svm_get_root_rp(); + + pthread_mutex_lock (&root_rp->mutex); + + mp = root_rp->data_base; + + for (j = 0; j < vec_len (root_rp->client_pids); j++) { + if (mypid == root_rp->client_pids[j]) + continue; + if (root_rp->client_pids[j] + && (kill (root_rp->client_pids[j], 0) < 0)) { + clib_warning ("%s: cleanup ghost pid %d", + root_rp->region_name, root_rp->client_pids[j]); + /* nb: client vec in root_rp->region_heap */ + oldheap = svm_push_pvt_heap (root_rp); + vec_delete (root_rp->client_pids, 1, j); + j--; + svm_pop_heap (oldheap); + } + } + + /* + * Snapshoot names, can't hold root rp mutex across + * find_or_create. + */ + pool_foreach (subp, mp->subregions, ({ + name = vec_dup (subp->subregion_name); + vec_add1(svm_names, name); + })); + + pthread_mutex_unlock (&root_rp->mutex); + + for (i = 0; i < vec_len(svm_names); i++) { + vec_validate(a, 0); + a->root_path = root_path; + a->name = (char *) svm_names[i]; + rp = svm_region_find_or_create (a); + if (rp) { + pthread_mutex_lock (&rp->mutex); + + svm_client_scan_this_region_nolock (rp); + + pthread_mutex_unlock (&rp->mutex); + svm_region_unmap (rp); + vec_free(svm_names[i]); + } + vec_free (a); + } + vec_free(svm_names); + + svm_region_exit (); + + vec_free (a); +} |