X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libringbuffer%2Fshm.c;h=3dbb9f4928a6d81b43c01fc1dbd4dbd3620ebf0c;hb=c0c0989ab70574e09b2f7e8b48c2da6af664a849;hp=8ac321e3931906888f79dd9e2419a7dbca8225de;hpb=429dadf0e28fe24be158ddb76d09f5f2308b6467;p=lttng-ust.git diff --git a/libringbuffer/shm.c b/libringbuffer/shm.c index 8ac321e3..3dbb9f49 100644 --- a/libringbuffer/shm.c +++ b/libringbuffer/shm.c @@ -1,21 +1,7 @@ /* - * libringbuffer/shm.c + * SPDX-License-Identifier: LGPL-2.1-only * * Copyright (C) 2005-2012 Mathieu Desnoyers - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; only - * version 2.1 of the License. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #define _LGPL_SOURCE @@ -32,16 +18,20 @@ #include #include #include +#include +#include +#ifdef HAVE_LIBNUMA +#include +#include +#endif #include #include +#include "mmap.h" /* * Ensure we have the required amount of space available by writing 0 * into the entire buffer. Not doing so can trigger SIGBUS when going * beyond the available shm space. - * - * Also ensure the file metadata is synced with the storage by using - * fsync(2). */ static int zero_file(int fd, size_t len) @@ -70,11 +60,6 @@ int zero_file(int fd, size_t len) } written += retlen; } - ret = fsync(fd); - if (ret) { - ret = (int) -errno; - goto error; - } ret = 0; error: free(zeropage); @@ -129,25 +114,44 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, } memcpy(obj->wait_fd, waitfd, sizeof(waitfd)); - /* create shm */ + /* + * Set POSIX shared memory object size + * + * First, use ftruncate() to set its size, some implementations won't + * allow writes past the size set by ftruncate. + * Then, use write() to fill it with zeros, this allows us to fully + * allocate it and detect a shortage of shm space without dealing with + * a SIGBUS. + */ shmfd = stream_fd; + ret = ftruncate(shmfd, memory_map_size); + if (ret) { + PERROR("ftruncate"); + goto error_ftruncate; + } ret = zero_file(shmfd, memory_map_size); if (ret) { PERROR("zero_file"); goto error_zero_file; } - ret = ftruncate(shmfd, memory_map_size); - if (ret) { - PERROR("ftruncate"); - goto error_ftruncate; + + /* + * Also ensure the file metadata is synced with the storage by using + * fsync(2). Some platforms don't allow fsync on POSIX shm fds, ignore + * EINVAL accordingly. + */ + ret = fsync(shmfd); + if (ret && errno != EINVAL) { + PERROR("fsync"); + goto error_fsync; } obj->shm_fd_ownership = 0; obj->shm_fd = shmfd; /* memory_map: mmap */ memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE, - MAP_SHARED, shmfd, 0); + MAP_SHARED | LTTNG_MAP_POPULATE, shmfd, 0); if (memory_map == MAP_FAILED) { PERROR("mmap"); goto error_mmap; @@ -161,6 +165,7 @@ struct shm_object *_shm_object_table_alloc_shm(struct shm_object_table *table, return obj; error_mmap: +error_fsync: error_ftruncate: error_zero_file: error_fcntl: @@ -238,21 +243,63 @@ 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, - int stream_fd) + 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, @@ -277,11 +324,6 @@ struct shm_object *shm_object_table_append_shm(struct shm_object_table *table, obj->shm_fd = shm_fd; obj->shm_fd_ownership = 1; - ret = fcntl(obj->wait_fd[1], F_SETFD, FD_CLOEXEC); - if (ret < 0) { - PERROR("fcntl"); - goto error_fcntl; - } /* The write end of the pipe needs to be non-blocking */ ret = fcntl(obj->wait_fd[1], F_SETFL, O_NONBLOCK); if (ret < 0) { @@ -291,7 +333,7 @@ struct shm_object *shm_object_table_append_shm(struct shm_object_table *table, /* memory_map: mmap */ memory_map = mmap(NULL, memory_map_size, PROT_READ | PROT_WRITE, - MAP_SHARED, shm_fd, 0); + MAP_SHARED | LTTNG_MAP_POPULATE, shm_fd, 0); if (memory_map == MAP_FAILED) { PERROR("mmap"); goto error_mmap; @@ -472,6 +514,6 @@ struct shm_ref zalloc_shm(struct shm_object *obj, size_t len) void align_shm(struct shm_object *obj, size_t align) { - size_t offset_len = offset_align(obj->allocated_len, align); + size_t offset_len = lttng_ust_offset_align(obj->allocated_len, align); obj->allocated_len += offset_len; }