X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=libringbuffer%2Fshm.c;h=10b3bcef110a979ce2169ccf10417e470e122ba9;hb=8a208943e21700211beee3ea64180a5a534c7d2a;hp=995665ae16f4ee0b4836b3ffaf047bfb76ec3193;hpb=af21f7816739b0f9db8b4006ef4378ddc2de0157;p=lttng-ust.git diff --git a/libringbuffer/shm.c b/libringbuffer/shm.c index 995665ae..10b3bcef 100644 --- a/libringbuffer/shm.c +++ b/libringbuffer/shm.c @@ -18,10 +18,13 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ +#define _LGPL_SOURCE +#include #include "shm.h" #include #include #include +#include #include /* For mode constants */ #include /* For O_* constants */ #include @@ -29,9 +32,14 @@ #include #include #include -#include #include +#include +#ifdef HAVE_LIBNUMA +#include +#include +#endif #include +#include /* * Ensure we have the required amount of space available by writing 0 @@ -77,20 +85,23 @@ struct shm_object_table *shm_object_table_create(size_t max_nb_obj) table = zmalloc(sizeof(struct shm_object_table) + max_nb_obj * sizeof(table->objects[0])); + if (!table) + return NULL; table->size = max_nb_obj; return table; } static struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, - size_t memory_map_size) + size_t memory_map_size, + int stream_fd) { - int shmfd, waitfd[2], ret, i, sigblocked = 0; + int shmfd, waitfd[2], ret, i; struct shm_object *obj; char *memory_map; - char tmp_name[NAME_MAX] = "/ust-shm-tmp-XXXXXX"; - sigset_t all_sigs, orig_sigs; + if (stream_fd < 0) + return NULL; if (table->allocated_len >= table->size) return NULL; obj = &table->objects[table->allocated_len]; @@ -116,58 +127,9 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, } memcpy(obj->wait_fd, waitfd, sizeof(waitfd)); - /* shm_fd: create shm */ + /* create shm */ - /* - * Theoretically, we could leak a shm if the application crashes - * between open and unlink. Disable signals on this thread for - * increased safety against this scenario. - */ - sigfillset(&all_sigs); - ret = pthread_sigmask(SIG_BLOCK, &all_sigs, &orig_sigs); - if (ret == -1) { - PERROR("pthread_sigmask"); - goto error_pthread_sigmask; - } - sigblocked = 1; - - /* - * Allocate shm, and immediately unlink its shm oject, keeping - * only the file descriptor as a reference to the object. If it - * already exists (caused by short race window during which the - * global object exists in a concurrent shm_open), simply retry. - * We specifically do _not_ use the / at the beginning of the - * pathname so that some OS implementations can keep it local to - * the process (POSIX leaves this implementation-defined). - */ - do { - /* - * Using mktemp filename with O_CREAT | O_EXCL open - * flags. - */ - (void) mktemp(tmp_name); - if (tmp_name[0] == '\0') { - PERROR("mktemp"); - goto error_shm_open; - } - shmfd = shm_open(tmp_name, - O_CREAT | O_EXCL | O_RDWR, 0700); - } while (shmfd < 0 && (errno == EEXIST || errno == EACCES)); - if (shmfd < 0) { - PERROR("shm_open"); - goto error_shm_open; - } - ret = shm_unlink(tmp_name); - if (ret < 0 && errno != ENOENT) { - PERROR("shm_unlink"); - goto error_shm_release; - } - sigblocked = 0; - ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL); - if (ret == -1) { - PERROR("pthread_sigmask"); - goto error_sigmask_release; - } + shmfd = stream_fd; ret = zero_file(shmfd, memory_map_size); if (ret) { PERROR("zero_file"); @@ -178,6 +140,16 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, PERROR("ftruncate"); goto error_ftruncate; } + /* + * Also ensure the file metadata is synced with the storage by using + * fsync(2). + */ + ret = fsync(shmfd); + if (ret) { + PERROR("fsync"); + goto error_fsync; + } + obj->shm_fd_ownership = 0; obj->shm_fd = shmfd; /* memory_map: mmap */ @@ -196,23 +168,9 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, return obj; error_mmap: +error_fsync: error_ftruncate: -error_shm_release: error_zero_file: -error_sigmask_release: - ret = close(shmfd); - if (ret) { - PERROR("close"); - assert(0); - } -error_shm_open: - if (sigblocked) { - ret = pthread_sigmask(SIG_SETMASK, &orig_sigs, NULL); - if (ret == -1) { - PERROR("pthread_sigmask"); - } - } -error_pthread_sigmask: error_fcntl: for (i = 0; i < 2; i++) { ret = close(waitfd[i]); @@ -264,6 +222,7 @@ struct shm_object *_shm_object_table_alloc_mem(struct shm_object_table *table, /* no shm_fd */ obj->shm_fd = -1; + obj->shm_fd_ownership = 0; obj->type = SHM_OBJECT_MEM; obj->memory_map = memory_map; @@ -287,19 +246,63 @@ alloc_error: return NULL; } +/* + * libnuma prints errors on the console even for numa_available(). + * Work-around this limitation by using get_mempolicy() directly to + * check whether the kernel supports mempolicy. + */ +#ifdef HAVE_LIBNUMA +static bool lttng_is_numa_available(void) +{ + int ret; + + ret = get_mempolicy(NULL, NULL, 0, NULL, 0); + if (ret && errno == ENOSYS) { + return false; + } + return numa_available() > 0; +} +#endif + struct shm_object *shm_object_table_alloc(struct shm_object_table *table, size_t memory_map_size, - enum shm_object_type type) + enum shm_object_type type, + int stream_fd, + int cpu) { + struct shm_object *shm_object; +#ifdef HAVE_LIBNUMA + int oldnode = 0, node; + bool numa_avail; + + numa_avail = lttng_is_numa_available(); + if (numa_avail) { + oldnode = numa_preferred(); + if (cpu >= 0) { + node = numa_node_of_cpu(cpu); + if (node >= 0) + numa_set_preferred(node); + } + if (cpu < 0 || node < 0) + numa_set_localalloc(); + } +#endif /* HAVE_LIBNUMA */ switch (type) { case SHM_OBJECT_SHM: - return _shm_object_table_alloc_shm(table, memory_map_size); + shm_object = _shm_object_table_alloc_shm(table, memory_map_size, + stream_fd); + break; case SHM_OBJECT_MEM: - return _shm_object_table_alloc_mem(table, memory_map_size); + shm_object = _shm_object_table_alloc_mem(table, memory_map_size); + break; default: assert(0); } - return NULL; +#ifdef HAVE_LIBNUMA + if (numa_avail) + numa_set_preferred(oldnode); +#endif /* HAVE_LIBNUMA */ + return shm_object; } struct shm_object *shm_object_table_append_shm(struct shm_object_table *table, @@ -322,6 +325,7 @@ struct shm_object *shm_object_table_append_shm(struct shm_object_table *table, obj->wait_fd[0] = -1; /* read end is unset */ obj->wait_fd[1] = wakeup_fd; obj->shm_fd = shm_fd; + obj->shm_fd_ownership = 1; ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC); if (ret < 0) { @@ -371,6 +375,7 @@ struct shm_object *shm_object_table_append_mem(struct shm_object_table *table, obj->wait_fd[0] = -1; /* read end is unset */ obj->wait_fd[1] = wakeup_fd; obj->shm_fd = -1; + obj->shm_fd_ownership = 0; ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC); if (ret < 0) { @@ -397,7 +402,7 @@ error_fcntl: } static -void shmp_object_destroy(struct shm_object *obj) +void shmp_object_destroy(struct shm_object *obj, int consumer) { switch (obj->type) { case SHM_OBJECT_SHM: @@ -409,18 +414,46 @@ void shmp_object_destroy(struct shm_object *obj) PERROR("umnmap"); assert(0); } - ret = close(obj->shm_fd); - if (ret) { - PERROR("close"); - assert(0); + + if (obj->shm_fd_ownership) { + /* Delete FDs only if called from app (not consumer). */ + if (!consumer) { + lttng_ust_lock_fd_tracker(); + ret = close(obj->shm_fd); + if (!ret) { + lttng_ust_delete_fd_from_tracker(obj->shm_fd); + } else { + PERROR("close"); + assert(0); + } + lttng_ust_unlock_fd_tracker(); + } else { + ret = close(obj->shm_fd); + if (ret) { + PERROR("close"); + assert(0); + } + } } for (i = 0; i < 2; i++) { if (obj->wait_fd[i] < 0) continue; - ret = close(obj->wait_fd[i]); - if (ret) { - PERROR("close"); - assert(0); + if (!consumer) { + lttng_ust_lock_fd_tracker(); + ret = close(obj->wait_fd[i]); + if (!ret) { + lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]); + } else { + PERROR("close"); + assert(0); + } + lttng_ust_unlock_fd_tracker(); + } else { + ret = close(obj->wait_fd[i]); + if (ret) { + PERROR("close"); + assert(0); + } } } break; @@ -432,10 +465,22 @@ void shmp_object_destroy(struct shm_object *obj) for (i = 0; i < 2; i++) { if (obj->wait_fd[i] < 0) continue; - ret = close(obj->wait_fd[i]); - if (ret) { - PERROR("close"); - assert(0); + if (!consumer) { + lttng_ust_lock_fd_tracker(); + ret = close(obj->wait_fd[i]); + if (!ret) { + lttng_ust_delete_fd_from_tracker(obj->wait_fd[i]); + } else { + PERROR("close"); + assert(0); + } + lttng_ust_unlock_fd_tracker(); + } else { + ret = close(obj->wait_fd[i]); + if (ret) { + PERROR("close"); + assert(0); + } } } free(obj->memory_map); @@ -446,12 +491,12 @@ void shmp_object_destroy(struct shm_object *obj) } } -void shm_object_table_destroy(struct shm_object_table *table) +void shm_object_table_destroy(struct shm_object_table *table, int consumer) { int i; for (i = 0; i < table->allocated_len; i++) - shmp_object_destroy(&table->objects[i]); + shmp_object_destroy(&table->objects[i], consumer); free(table); }