+++ /dev/null
-/*
- * ring_buffer_backend.c
- *
- * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * 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 _GNU_SOURCE
-#include <unistd.h>
-#include <urcu/arch.h>
-#include <limits.h>
-
-#include <lttng/ringbuffer-config.h>
-#include "vatomic.h"
-#include "backend.h"
-#include "frontend.h"
-#include "smp.h"
-#include "shm.h"
-
-/**
- * lib_ring_buffer_backend_allocate - allocate a channel buffer
- * @config: ring buffer instance configuration
- * @buf: the buffer struct
- * @size: total size of the buffer
- * @num_subbuf: number of subbuffers
- * @extra_reader_sb: need extra subbuffer for reader
- */
-static
-int lib_ring_buffer_backend_allocate(const struct lttng_ust_lib_ring_buffer_config *config,
- struct lttng_ust_lib_ring_buffer_backend *bufb,
- size_t size, size_t num_subbuf,
- int extra_reader_sb,
- struct lttng_ust_shm_handle *handle,
- struct shm_object *shmobj)
-{
- struct channel_backend *chanb;
- unsigned long subbuf_size, mmap_offset = 0;
- unsigned long num_subbuf_alloc;
- unsigned long i;
- long page_size;
-
- chanb = &shmp(handle, bufb->chan)->backend;
- if (!chanb)
- return -EINVAL;
-
- subbuf_size = chanb->subbuf_size;
- num_subbuf_alloc = num_subbuf;
-
- if (extra_reader_sb)
- num_subbuf_alloc++;
-
- page_size = sysconf(_SC_PAGE_SIZE);
- if (page_size <= 0) {
- goto page_size_error;
- }
-
- align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp));
- set_shmp(bufb->array, zalloc_shm(shmobj,
- sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc));
- if (caa_unlikely(!shmp(handle, bufb->array)))
- goto array_error;
-
- /*
- * This is the largest element (the buffer pages) which needs to
- * be aligned on page size.
- */
- align_shm(shmobj, page_size);
- set_shmp(bufb->memory_map, zalloc_shm(shmobj,
- subbuf_size * num_subbuf_alloc));
- if (caa_unlikely(!shmp(handle, bufb->memory_map)))
- goto memory_map_error;
-
- /* Allocate backend pages array elements */
- for (i = 0; i < num_subbuf_alloc; i++) {
- align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages));
- set_shmp(shmp_index(handle, bufb->array, i)->shmp,
- zalloc_shm(shmobj,
- sizeof(struct lttng_ust_lib_ring_buffer_backend_pages)));
- if (!shmp(handle, shmp_index(handle, bufb->array, i)->shmp))
- goto free_array;
- }
-
- /* Allocate write-side subbuffer table */
- align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer));
- set_shmp(bufb->buf_wsb, zalloc_shm(shmobj,
- sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer)
- * num_subbuf));
- if (caa_unlikely(!shmp(handle, bufb->buf_wsb)))
- goto free_array;
-
- for (i = 0; i < num_subbuf; i++) {
- struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb;
-
- sb = shmp_index(handle, bufb->buf_wsb, i);
- if (!sb)
- goto free_array;
- sb->id = subbuffer_id(config, 0, 1, i);
- }
-
- /* Assign read-side subbuffer table */
- if (extra_reader_sb)
- bufb->buf_rsb.id = subbuffer_id(config, 0, 1,
- num_subbuf_alloc - 1);
- else
- bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0);
-
- /* Allocate subbuffer packet counter table */
- align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer));
- set_shmp(bufb->buf_cnt, zalloc_shm(shmobj,
- sizeof(struct lttng_ust_lib_ring_buffer_backend_counts)
- * num_subbuf));
- if (caa_unlikely(!shmp(handle, bufb->buf_cnt)))
- goto free_wsb;
-
- /* Assign pages to page index */
- for (i = 0; i < num_subbuf_alloc; i++) {
- struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp;
- struct lttng_ust_lib_ring_buffer_backend_pages *pages;
- struct shm_ref ref;
-
- ref.index = bufb->memory_map._ref.index;
- ref.offset = bufb->memory_map._ref.offset;
- ref.offset += i * subbuf_size;
-
- sbp = shmp_index(handle, bufb->array, i);
- if (!sbp)
- goto free_array;
- pages = shmp(handle, sbp->shmp);
- if (!pages)
- goto free_array;
- set_shmp(pages->p, ref);
- if (config->output == RING_BUFFER_MMAP) {
- pages->mmap_offset = mmap_offset;
- mmap_offset += subbuf_size;
- }
- }
- return 0;
-
-free_wsb:
- /* bufb->buf_wsb will be freed by shm teardown */
-free_array:
- /* bufb->array[i] will be freed by shm teardown */
-memory_map_error:
- /* bufb->array will be freed by shm teardown */
-array_error:
-page_size_error:
- return -ENOMEM;
-}
-
-int lib_ring_buffer_backend_create(struct lttng_ust_lib_ring_buffer_backend *bufb,
- struct channel_backend *chanb, int cpu,
- struct lttng_ust_shm_handle *handle,
- struct shm_object *shmobj)
-{
- const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config;
-
- set_shmp(bufb->chan, handle->chan._ref);
- bufb->cpu = cpu;
-
- return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size,
- chanb->num_subbuf,
- chanb->extra_reader_sb,
- handle, shmobj);
-}
-
-void lib_ring_buffer_backend_reset(struct lttng_ust_lib_ring_buffer_backend *bufb,
- struct lttng_ust_shm_handle *handle)
-{
- struct channel_backend *chanb;
- const struct lttng_ust_lib_ring_buffer_config *config;
- unsigned long num_subbuf_alloc;
- unsigned int i;
-
- chanb = &shmp(handle, bufb->chan)->backend;
- if (!chanb)
- abort();
- config = &chanb->config;
-
- num_subbuf_alloc = chanb->num_subbuf;
- if (chanb->extra_reader_sb)
- num_subbuf_alloc++;
-
- for (i = 0; i < chanb->num_subbuf; i++) {
- struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb;
-
- sb = shmp_index(handle, bufb->buf_wsb, i);
- if (!sb)
- abort();
- sb->id = subbuffer_id(config, 0, 1, i);
- }
- if (chanb->extra_reader_sb)
- bufb->buf_rsb.id = subbuffer_id(config, 0, 1,
- num_subbuf_alloc - 1);
- else
- bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0);
-
- for (i = 0; i < num_subbuf_alloc; i++) {
- struct lttng_ust_lib_ring_buffer_backend_pages_shmp *sbp;
- struct lttng_ust_lib_ring_buffer_backend_pages *pages;
-
- sbp = shmp_index(handle, bufb->array, i);
- if (!sbp)
- abort();
- pages = shmp(handle, sbp->shmp);
- if (!pages)
- abort();
- /* Don't reset mmap_offset */
- v_set(config, &pages->records_commit, 0);
- v_set(config, &pages->records_unread, 0);
- pages->data_size = 0;
- /* Don't reset backend page and virt addresses */
- }
- /* Don't reset num_pages_per_subbuf, cpu, allocated */
- v_set(config, &bufb->records_read, 0);
-}
-
-/*
- * The frontend is responsible for also calling ring_buffer_backend_reset for
- * each buffer when calling channel_backend_reset.
- */
-void channel_backend_reset(struct channel_backend *chanb)
-{
- struct channel *chan = caa_container_of(chanb, struct channel, backend);
- const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config;
-
- /*
- * Don't reset buf_size, subbuf_size, subbuf_size_order,
- * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf,
- * priv, notifiers, config, cpumask and name.
- */
- chanb->start_tsc = config->cb.ring_buffer_clock_read(chan);
-}
-
-/**
- * channel_backend_init - initialize a channel backend
- * @chanb: channel backend
- * @name: channel name
- * @config: client ring buffer configuration
- * @parent: dentry of parent directory, %NULL for root directory
- * @subbuf_size: size of sub-buffers (> page size, power of 2)
- * @num_subbuf: number of sub-buffers (power of 2)
- * @lttng_ust_shm_handle: shared memory handle
- * @stream_fds: stream file descriptors.
- *
- * Returns channel pointer if successful, %NULL otherwise.
- *
- * Creates per-cpu channel buffers using the sizes and attributes
- * specified. The created channel buffer files will be named
- * name_0...name_N-1. File permissions will be %S_IRUSR.
- *
- * Called with CPU hotplug disabled.
- */
-int channel_backend_init(struct channel_backend *chanb,
- const char *name,
- const struct lttng_ust_lib_ring_buffer_config *config,
- size_t subbuf_size, size_t num_subbuf,
- struct lttng_ust_shm_handle *handle,
- const int *stream_fds)
-{
- struct channel *chan = caa_container_of(chanb, struct channel, backend);
- unsigned int i;
- int ret;
- size_t shmsize = 0, num_subbuf_alloc;
- long page_size;
-
- if (!name)
- return -EPERM;
-
- page_size = sysconf(_SC_PAGE_SIZE);
- if (page_size <= 0) {
- return -ENOMEM;
- }
- /* Check that the subbuffer size is larger than a page. */
- if (subbuf_size < page_size)
- return -EINVAL;
-
- /*
- * Make sure the number of subbuffers and subbuffer size are
- * power of 2, and nonzero.
- */
- if (!subbuf_size || (subbuf_size & (subbuf_size - 1)))
- return -EINVAL;
- if (!num_subbuf || (num_subbuf & (num_subbuf - 1)))
- return -EINVAL;
- /*
- * Overwrite mode buffers require at least 2 subbuffers per
- * buffer.
- */
- if (config->mode == RING_BUFFER_OVERWRITE && num_subbuf < 2)
- return -EINVAL;
-
- ret = subbuffer_id_check_index(config, num_subbuf);
- if (ret)
- return ret;
-
- chanb->buf_size = num_subbuf * subbuf_size;
- chanb->subbuf_size = subbuf_size;
- chanb->buf_size_order = get_count_order(chanb->buf_size);
- chanb->subbuf_size_order = get_count_order(subbuf_size);
- chanb->num_subbuf_order = get_count_order(num_subbuf);
- chanb->extra_reader_sb =
- (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0;
- chanb->num_subbuf = num_subbuf;
- strncpy(chanb->name, name, NAME_MAX);
- chanb->name[NAME_MAX - 1] = '\0';
- memcpy(&chanb->config, config, sizeof(*config));
-
- /* Per-cpu buffer size: control (prior to backend) */
- shmsize = offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer));
- shmsize += sizeof(struct lttng_ust_lib_ring_buffer);
-
- /* Per-cpu buffer size: backend */
- /* num_subbuf + 1 is the worse case */
- num_subbuf_alloc = num_subbuf + 1;
- shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages_shmp));
- shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages_shmp) * num_subbuf_alloc;
- shmsize += offset_align(shmsize, page_size);
- shmsize += subbuf_size * num_subbuf_alloc;
- shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_pages));
- shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_pages) * num_subbuf_alloc;
- shmsize += offset_align(shmsize, __alignof__(struct lttng_ust_lib_ring_buffer_backend_subbuffer));
- shmsize += sizeof(struct lttng_ust_lib_ring_buffer_backend_subbuffer) * num_subbuf;
- /* Per-cpu buffer size: control (after backend) */
- shmsize += offset_align(shmsize, __alignof__(struct commit_counters_hot));
- shmsize += sizeof(struct commit_counters_hot) * num_subbuf;
- shmsize += offset_align(shmsize, __alignof__(struct commit_counters_cold));
- shmsize += sizeof(struct commit_counters_cold) * num_subbuf;
-
- if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) {
- struct lttng_ust_lib_ring_buffer *buf;
- /*
- * We need to allocate for all possible cpus.
- */
- for_each_possible_cpu(i) {
- struct shm_object *shmobj;
-
- shmobj = shm_object_table_alloc(handle->table, shmsize,
- SHM_OBJECT_SHM, stream_fds[i]);
- if (!shmobj)
- goto end;
- align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer));
- set_shmp(chanb->buf[i].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer)));
- buf = shmp(handle, chanb->buf[i].shmp);
- if (!buf)
- goto end;
- set_shmp(buf->self, chanb->buf[i].shmp._ref);
- ret = lib_ring_buffer_create(buf, chanb, i,
- handle, shmobj);
- if (ret)
- goto free_bufs; /* cpu hotplug locked */
- }
- } else {
- struct shm_object *shmobj;
- struct lttng_ust_lib_ring_buffer *buf;
-
- shmobj = shm_object_table_alloc(handle->table, shmsize,
- SHM_OBJECT_SHM, stream_fds[0]);
- if (!shmobj)
- goto end;
- align_shm(shmobj, __alignof__(struct lttng_ust_lib_ring_buffer));
- set_shmp(chanb->buf[0].shmp, zalloc_shm(shmobj, sizeof(struct lttng_ust_lib_ring_buffer)));
- buf = shmp(handle, chanb->buf[0].shmp);
- if (!buf)
- goto end;
- set_shmp(buf->self, chanb->buf[0].shmp._ref);
- ret = lib_ring_buffer_create(buf, chanb, -1,
- handle, shmobj);
- if (ret)
- goto free_bufs;
- }
- chanb->start_tsc = config->cb.ring_buffer_clock_read(chan);
-
- return 0;
-
-free_bufs:
- /* We only free the buffer data upon shm teardown */
-end:
- return -ENOMEM;
-}
-
-/**
- * channel_backend_free - destroy the channel
- * @chan: the channel
- *
- * Destroy all channel buffers and frees the channel.
- */
-void channel_backend_free(struct channel_backend *chanb,
- struct lttng_ust_shm_handle *handle)
-{
- /* SHM teardown takes care of everything */
-}
-
-/**
- * lib_ring_buffer_read - read data from ring_buffer_buffer.
- * @bufb : buffer backend
- * @offset : offset within the buffer
- * @dest : destination address
- * @len : length to copy to destination
- *
- * Should be protected by get_subbuf/put_subbuf.
- * Returns the length copied.
- */
-size_t lib_ring_buffer_read(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset,
- void *dest, size_t len, struct lttng_ust_shm_handle *handle)
-{
- struct channel_backend *chanb;
- const struct lttng_ust_lib_ring_buffer_config *config;
- ssize_t orig_len;
- struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages;
- unsigned long sb_bindex, id;
- void *src;
-
- chanb = &shmp(handle, bufb->chan)->backend;
- if (!chanb)
- return 0;
- config = &chanb->config;
- orig_len = len;
- offset &= chanb->buf_size - 1;
-
- if (caa_unlikely(!len))
- return 0;
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = shmp_index(handle, bufb->array, sb_bindex);
- /*
- * Underlying layer should never ask for reads across
- * subbuffers.
- */
- CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- src = shmp_index(handle, shmp(handle, rpages->shmp)->p,
- offset & (chanb->subbuf_size - 1));
- if (caa_unlikely(!src))
- return 0;
- memcpy(dest, src, len);
- return orig_len;
-}
-
-/**
- * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer.
- * @bufb : buffer backend
- * @offset : offset within the buffer
- * @dest : destination address
- * @len : destination's length
- *
- * Return string's length, or -EINVAL on error.
- * Should be protected by get_subbuf/put_subbuf.
- * Destination length should be at least 1 to hold '\0'.
- */
-int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset,
- void *dest, size_t len, struct lttng_ust_shm_handle *handle)
-{
- struct channel_backend *chanb;
- const struct lttng_ust_lib_ring_buffer_config *config;
- ssize_t string_len, orig_offset;
- char *str;
- struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages;
- unsigned long sb_bindex, id;
-
- chanb = &shmp(handle, bufb->chan)->backend;
- if (!chanb)
- return -EINVAL;
- config = &chanb->config;
- if (caa_unlikely(!len))
- return -EINVAL;
- offset &= chanb->buf_size - 1;
- orig_offset = offset;
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = shmp_index(handle, bufb->array, sb_bindex);
- /*
- * Underlying layer should never ask for reads across
- * subbuffers.
- */
- CHAN_WARN_ON(chanb, offset >= chanb->buf_size);
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- str = shmp_index(handle, shmp(handle, rpages->shmp)->p, offset & (chanb->subbuf_size - 1));
- if (caa_unlikely(!str))
- return -EINVAL;
- string_len = strnlen(str, len);
- if (dest && len) {
- memcpy(dest, str, string_len);
- ((char *)dest)[0] = 0;
- }
- return offset - orig_offset;
-}
-
-/**
- * lib_ring_buffer_read_offset_address - get address of a buffer location
- * @bufb : buffer backend
- * @offset : offset within the buffer.
- *
- * Return the address where a given offset is located (for read).
- * Should be used to get the current subbuffer header pointer. Given we know
- * it's never on a page boundary, it's safe to read/write directly
- * from/to this address, as long as the read/write is never bigger than
- * a page size.
- */
-void *lib_ring_buffer_read_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb,
- size_t offset,
- struct lttng_ust_shm_handle *handle)
-{
- struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages;
- struct channel_backend *chanb;
- const struct lttng_ust_lib_ring_buffer_config *config;
- unsigned long sb_bindex, id;
-
- chanb = &shmp(handle, bufb->chan)->backend;
- if (!chanb)
- return NULL;
- config = &chanb->config;
- offset &= chanb->buf_size - 1;
- id = bufb->buf_rsb.id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = shmp_index(handle, bufb->array, sb_bindex);
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- return shmp_index(handle, shmp(handle, rpages->shmp)->p, offset & (chanb->subbuf_size - 1));
-}
-
-/**
- * lib_ring_buffer_offset_address - get address of a location within the buffer
- * @bufb : buffer backend
- * @offset : offset within the buffer.
- *
- * Return the address where a given offset is located.
- * Should be used to get the current subbuffer header pointer. Given we know
- * it's always at the beginning of a page, it's safe to write directly to this
- * address, as long as the write is never bigger than a page size.
- */
-void *lib_ring_buffer_offset_address(struct lttng_ust_lib_ring_buffer_backend *bufb,
- size_t offset,
- struct lttng_ust_shm_handle *handle)
-{
- size_t sbidx;
- struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages;
- struct channel_backend *chanb;
- const struct lttng_ust_lib_ring_buffer_config *config;
- unsigned long sb_bindex, id;
- struct lttng_ust_lib_ring_buffer_backend_subbuffer *sb;
-
- chanb = &shmp(handle, bufb->chan)->backend;
- if (!chanb)
- return NULL;
- config = &chanb->config;
- offset &= chanb->buf_size - 1;
- sbidx = offset >> chanb->subbuf_size_order;
- sb = shmp_index(handle, bufb->buf_wsb, sbidx);
- if (!sb)
- return NULL;
- id = sb->id;
- sb_bindex = subbuffer_id_get_index(config, id);
- rpages = shmp_index(handle, bufb->array, sb_bindex);
- CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE
- && subbuffer_id_is_noref(config, id));
- return shmp_index(handle, shmp(handle, rpages->shmp)->p, offset & (chanb->subbuf_size - 1));
-}
projects / lttng-ust.git / blobdiff