From: Mathieu Desnoyers Date: Fri, 26 Aug 2011 10:29:29 +0000 (-0400) Subject: Remove deprecated files X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=37c71fc050181b915b3b14731f2875a3b2788daa;p=ust.git Remove deprecated files Signed-off-by: Mathieu Desnoyers --- diff --git a/libust/buffers.c b/libust/buffers.c deleted file mode 100644 index 5e67d54..0000000 --- a/libust/buffers.c +++ /dev/null @@ -1,1140 +0,0 @@ -/* - * buffers.c - * LTTng userspace tracer buffering system - * - * Copyright (C) 2009 - Pierre-Marc Fournier (pierre-marc dot fournier at polymtl dot ca) - * Copyright (C) 2008-2011 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) - * - * 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; 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 - */ - -/* - * Note: this code does not support the ref/noref flag and reader-owned - * subbuffer scheme. Therefore, flight recorder mode uses a mechanism - * where the reader can read corrupted data (and detect this), thus - * returning -EIO. - */ - -#include -#include -#include -#include -#include -#include - -#include - -#include "buffers.h" -#include "channels.h" -#include "tracer.h" -#include "tracercore.h" -#include - -struct ltt_reserve_switch_offsets { - long begin, end, old; - long begin_switch, end_switch_current, end_switch_old; - size_t before_hdr_pad, size; -}; - - -static DEFINE_MUTEX(ust_buffers_channels_mutex); -static CDS_LIST_HEAD(ust_buffers_channels); - -static void ltt_force_switch(struct ust_buffer *buf, - enum force_switch_mode mode); - -/** - * _ust_buffers_strncpy_fixup - Fix an incomplete string in a ltt_relay buffer. - * @buf : buffer - * @offset : offset within the buffer - * @len : length to write - * @copied: string actually copied - * @terminated: does string end with \0 - * - * Fills string with "X" if incomplete. - */ -void _ust_buffers_strncpy_fixup(struct ust_buffer *buf, size_t offset, - size_t len, size_t copied, int terminated) -{ - size_t buf_offset, cpy; - - if (copied == len) { - /* - * Deal with non-terminated string. - */ - assert(!terminated); - offset += copied - 1; - buf_offset = BUFFER_OFFSET(offset, buf->chan); - /* - * Underlying layer should never ask for writes across - * subbuffers. - */ - assert(buf_offset - < buf->chan->subbuf_size*buf->chan->subbuf_cnt); - ust_buffers_do_memset(buf->buf_data + buf_offset, '\0', 1); - return; - } - - /* - * Deal with incomplete string. - * Overwrite string's \0 with X too. - */ - cpy = copied - 1; - assert(terminated); - len -= cpy; - offset += cpy; - buf_offset = BUFFER_OFFSET(offset, buf->chan); - - /* - * Underlying layer should never ask for writes across subbuffers. - */ - assert(buf_offset - < buf->chan->subbuf_size*buf->chan->subbuf_cnt); - - ust_buffers_do_memset(buf->buf_data + buf_offset, - 'X', len); - - /* - * Overwrite last 'X' with '\0'. - */ - offset += len - 1; - buf_offset = BUFFER_OFFSET(offset, buf->chan); - /* - * Underlying layer should never ask for writes across subbuffers. - */ - assert(buf_offset - < buf->chan->subbuf_size*buf->chan->subbuf_cnt); - ust_buffers_do_memset(buf->buf_data + buf_offset, '\0', 1); -} - -static void ltt_buffer_begin(struct ust_buffer *buf, - u64 tsc, unsigned int subbuf_idx) -{ - struct ust_channel *channel = buf->chan; - struct ltt_subbuffer_header *header = - (struct ltt_subbuffer_header *) - ust_buffers_offset_address(buf, - subbuf_idx * buf->chan->subbuf_size); - - header->cycle_count_begin = tsc; - header->data_size = 0xFFFFFFFF; /* for recognizing crashed buffers */ - header->sb_size = 0xFFFFFFFF; /* for recognizing crashed buffers */ - /* - * No memory barrier needed to order data_data/sb_size vs commit count - * update, because commit count update contains a compiler barrier that - * ensures the order of the writes are OK from a program POV. It only - * matters for crash dump recovery which is not executed concurrently, - * so memory write order does not matter. - */ - ltt_write_trace_header(channel->trace, header); -} - -static int map_buf_data(struct ust_buffer *buf, size_t *size) -{ - void *ptr; - int result; - - *size = PAGE_ALIGN(*size); - - result = buf->shmid = shmget(getpid(), *size, IPC_CREAT | IPC_EXCL | 0700); - if (result < 0 && errno == EINVAL) { - ERR("shmget() returned EINVAL; maybe /proc/sys/kernel/shmmax should be increased."); - return -1; - } else if (result < 0) { - PERROR("shmget"); - return -1; - } - - ptr = shmat(buf->shmid, NULL, 0); - if (ptr == (void *) -1) { - perror("shmat"); - goto destroy_shmem; - } - - /* Already mark the shared memory for destruction. This will occur only - * when all users have detached. - */ - result = shmctl(buf->shmid, IPC_RMID, NULL); - if(result == -1) { - perror("shmctl"); - return -1; - } - - buf->buf_data = ptr; - buf->buf_size = *size; - - return 0; - -destroy_shmem: - result = shmctl(buf->shmid, IPC_RMID, NULL); - if(result == -1) { - perror("shmctl"); - } - - return -1; -} - -static int open_buf(struct ust_channel *chan, int cpu) -{ - int result, fds[2]; - unsigned int j; - struct ust_trace *trace = chan->trace; - struct ust_buffer *buf = chan->buf[cpu]; - unsigned int n_subbufs = chan->subbuf_cnt; - - - result = map_buf_data(buf, &chan->alloc_size); - if (result < 0) - return -1; - - buf->commit_count = - zmalloc(sizeof(*buf->commit_count) * n_subbufs); - if (!buf->commit_count) - goto unmap_buf; - - result = pipe(fds); - if (result < 0) { - PERROR("pipe"); - goto free_commit_count; - } - buf->data_ready_fd_read = fds[0]; - buf->data_ready_fd_write = fds[1]; - - buf->cpu = cpu; - buf->chan = chan; - - uatomic_set(&buf->offset, ltt_subbuffer_header_size()); - uatomic_set(&buf->consumed, 0); - uatomic_set(&buf->active_readers, 0); - for (j = 0; j < n_subbufs; j++) { - uatomic_set(&buf->commit_count[j].cc, 0); - uatomic_set(&buf->commit_count[j].cc_sb, 0); - } - - ltt_buffer_begin(buf, trace->start_tsc, 0); - - uatomic_add(&buf->commit_count[0].cc, ltt_subbuffer_header_size()); - - uatomic_set(&buf->events_lost, 0); - uatomic_set(&buf->corrupted_subbuffers, 0); - - memset(buf->commit_seq, 0, sizeof(buf->commit_seq[0]) * n_subbufs); - - return 0; - -free_commit_count: - free(buf->commit_count); - -unmap_buf: - if (shmdt(buf->buf_data) < 0) { - PERROR("shmdt failed"); - } - - return -1; -} - -static void close_buf(struct ust_buffer *buf) -{ - int result; - - result = shmdt(buf->buf_data); - if (result < 0) { - PERROR("shmdt"); - } - - result = close(buf->data_ready_fd_read); - if (result < 0) { - PERROR("close"); - } - - result = close(buf->data_ready_fd_write); - if (result < 0 && errno != EBADF) { - PERROR("close"); - } -} - - -static int open_channel(struct ust_channel *chan, size_t subbuf_size, - size_t subbuf_cnt) -{ - int i; - int result; - - if(subbuf_size == 0 || subbuf_cnt == 0) - return -1; - - /* Check that the subbuffer size is larger than a page. */ - WARN_ON_ONCE(subbuf_size < PAGE_SIZE); - - /* - * Make sure the number of subbuffers and subbuffer size are power of 2. - */ - WARN_ON_ONCE(hweight32(subbuf_size) != 1); - WARN_ON(hweight32(subbuf_cnt) != 1); - - chan->version = UST_CHANNEL_VERSION; - chan->subbuf_cnt = subbuf_cnt; - chan->subbuf_size = subbuf_size; - chan->subbuf_size_order = get_count_order(subbuf_size); - chan->alloc_size = subbuf_size * subbuf_cnt; - - pthread_mutex_lock(&ust_buffers_channels_mutex); - for (i=0; i < chan->n_cpus; i++) { - result = open_buf(chan, i); - if (result == -1) - goto error; - } - cds_list_add(&chan->list, &ust_buffers_channels); - pthread_mutex_unlock(&ust_buffers_channels_mutex); - - return 0; - - /* Error handling */ -error: - for(i--; i >= 0; i--) - close_buf(chan->buf[i]); - - pthread_mutex_unlock(&ust_buffers_channels_mutex); - return -1; -} - -static void close_channel(struct ust_channel *chan) -{ - int i; - if(!chan) - return; - - pthread_mutex_lock(&ust_buffers_channels_mutex); - /* - * checking for chan->buf[i] being NULL or not is useless in - * practice because we allocate buffers for all possible cpus. - * However, should we decide to change this and only allocate - * for online cpus, this check becomes useful. - */ - for (i=0; in_cpus; i++) { - if (chan->buf[i]) - close_buf(chan->buf[i]); - } - - cds_list_del(&chan->list); - - pthread_mutex_unlock(&ust_buffers_channels_mutex); -} - -/* - * offset is assumed to never be 0 here : never deliver a completely empty - * subbuffer. The lost size is between 0 and subbuf_size-1. - */ -static notrace void ltt_buffer_end(struct ust_buffer *buf, - u64 tsc, unsigned int offset, unsigned int subbuf_idx) -{ - struct ltt_subbuffer_header *header = - (struct ltt_subbuffer_header *) - ust_buffers_offset_address(buf, - subbuf_idx * buf->chan->subbuf_size); - u32 data_size = SUBBUF_OFFSET(offset - 1, buf->chan) + 1; - - header->sb_size = PAGE_ALIGN(data_size); - header->cycle_count_end = tsc; - header->events_lost = uatomic_read(&buf->events_lost); - header->subbuf_corrupt = uatomic_read(&buf->corrupted_subbuffers); - if(unlikely(header->events_lost > 0)) { - DBG("Some events (%d) were lost in %s_%d", header->events_lost, buf->chan->channel_name, buf->cpu); - } - /* - * Makes sure data_size write happens after write of the rest of the - * buffer end data, because data_size is used to identify a completely - * written subbuffer in a crash dump. - */ - cmm_barrier(); - header->data_size = data_size; -} - -/* - * This function should not be called from NMI interrupt context - */ -static notrace void ltt_buf_unfull(struct ust_buffer *buf, - unsigned int subbuf_idx, - long offset) -{ -} - -/* - * Promote compiler cmm_barrier to a smp_mb(). - * For the specific LTTng case, this IPI call should be removed if the - * architecture does not reorder writes. This should eventually be provided by - * a separate architecture-specific infrastructure. - */ -//ust// static void remote_mb(void *info) -//ust// { -//ust// smp_mb(); -//ust// } - -int ust_buffers_get_subbuf(struct ust_buffer *buf, long *consumed) -{ - struct ust_channel *channel = buf->chan; - long consumed_old, consumed_idx, commit_count, write_offset; -//ust// int retval; - - consumed_old = uatomic_read(&buf->consumed); - consumed_idx = SUBBUF_INDEX(consumed_old, buf->chan); - commit_count = uatomic_read(&buf->commit_count[consumed_idx].cc_sb); - /* - * Make sure we read the commit count before reading the buffer - * data and the write offset. Correct consumed offset ordering - * wrt commit count is insured by the use of cmpxchg to update - * the consumed offset. - */ - - /* - * Local rmb to match the remote wmb to read the commit count before the - * buffer data and the write offset. - */ - cmm_smp_rmb(); - - write_offset = uatomic_read(&buf->offset); - /* - * Check that the subbuffer we are trying to consume has been - * already fully committed. - */ - if (((commit_count - buf->chan->subbuf_size) - & channel->commit_count_mask) - - (BUFFER_TRUNC(consumed_old, buf->chan) - >> channel->n_subbufs_order) - != 0) { - return -EAGAIN; - } - /* - * Check that we are not about to read the same subbuffer in - * which the writer head is. - */ - if ((SUBBUF_TRUNC(write_offset, buf->chan) - - SUBBUF_TRUNC(consumed_old, buf->chan)) - == 0) { - return -EAGAIN; - } - *consumed = consumed_old; - - return 0; -} - -int ust_buffers_put_subbuf(struct ust_buffer *buf, unsigned long uconsumed_old) -{ - long consumed_new, consumed_old; - - consumed_old = uatomic_read(&buf->consumed); - consumed_old = consumed_old & (~0xFFFFFFFFL); - consumed_old = consumed_old | uconsumed_old; - consumed_new = SUBBUF_ALIGN(consumed_old, buf->chan); - - if (uatomic_cmpxchg(&buf->consumed, consumed_old, - consumed_new) - != consumed_old) { - /* We have been pushed by the writer : the last - * buffer read _is_ corrupted! It can also - * happen if this is a buffer we never got. */ - return -EIO; - } else { - /* tell the client that buffer is now unfull */ - int index; - long data; - index = SUBBUF_INDEX(consumed_old, buf->chan); - data = BUFFER_OFFSET(consumed_old, buf->chan); - ltt_buf_unfull(buf, index, data); - } - return 0; -} - -static int map_buf_structs(struct ust_channel *chan) -{ - void *ptr; - int result; - size_t size; - int i; - - size = PAGE_ALIGN(1); - - for(i=0; in_cpus; i++) { - - result = chan->buf_struct_shmids[i] = shmget(getpid(), size, IPC_CREAT | IPC_EXCL | 0700); - if(result == -1) { - PERROR("shmget"); - goto destroy_previous; - } - - ptr = shmat(chan->buf_struct_shmids[i], NULL, 0); - if(ptr == (void *) -1) { - perror("shmat"); - goto destroy_shm; - } - - /* Already mark the shared memory for destruction. This will occur only - * when all users have detached. - */ - result = shmctl(chan->buf_struct_shmids[i], IPC_RMID, NULL); - if(result == -1) { - perror("shmctl"); - goto destroy_previous; - } - - chan->buf[i] = ptr; - } - - return 0; - - /* Jumping inside this loop occurs from within the other loop above with i as - * counter, so it unallocates the structures for the cpu = current_i down to - * zero. */ - for(; i>=0; i--) { - destroy_shm: - result = shmctl(chan->buf_struct_shmids[i], IPC_RMID, NULL); - if(result == -1) { - perror("shmctl"); - } - - destroy_previous: - continue; - } - - return -1; -} - -static int unmap_buf_structs(struct ust_channel *chan) -{ - int i; - - for (i=0; i < chan->n_cpus; i++) { - if (shmdt(chan->buf[i]) < 0) { - PERROR("shmdt"); - } - } - return 0; -} - -/* - * Create channel. - */ -static int create_channel(const char *trace_name, struct ust_trace *trace, - const char *channel_name, struct ust_channel *chan, - unsigned int subbuf_size, unsigned int n_subbufs, int overwrite) -{ - int i, result; - - chan->trace = trace; - chan->overwrite = overwrite; - chan->n_subbufs_order = get_count_order(n_subbufs); - chan->commit_count_mask = (~0UL >> chan->n_subbufs_order); - chan->n_cpus = get_n_cpus(); - - /* These mappings should ideall be per-cpu, if somebody can do that - * from userspace, that would be cool! - */ - chan->buf = (void *) zmalloc(chan->n_cpus * sizeof(void *)); - if(chan->buf == NULL) { - goto error; - } - chan->buf_struct_shmids = (int *) zmalloc(chan->n_cpus * sizeof(int)); - if(chan->buf_struct_shmids == NULL) - goto free_buf; - - result = map_buf_structs(chan); - if(result != 0) { - goto free_buf_struct_shmids; - } - - result = open_channel(chan, subbuf_size, n_subbufs); - if (result != 0) { - ERR("Cannot open channel for trace %s", trace_name); - goto unmap_buf_structs; - } - - return 0; - -unmap_buf_structs: - for (i=0; i < chan->n_cpus; i++) { - if (shmdt(chan->buf[i]) < 0) { - PERROR("shmdt bufstruct"); - } - } - -free_buf_struct_shmids: - free(chan->buf_struct_shmids); - -free_buf: - free(chan->buf); - -error: - return -1; -} - - -static void remove_channel(struct ust_channel *chan) -{ - close_channel(chan); - - unmap_buf_structs(chan); - - free(chan->buf_struct_shmids); - - free(chan->buf); -} - -static void ltt_relay_async_wakeup_chan(struct ust_channel *ltt_channel) -{ -} - -static void ltt_relay_finish_buffer(struct ust_channel *channel, unsigned int cpu) -{ - if (channel->buf[cpu]) { - struct ust_buffer *buf = channel->buf[cpu]; - ltt_force_switch(buf, FORCE_FLUSH); - - /* closing the pipe tells the consumer the buffer is finished */ - close(buf->data_ready_fd_write); - } -} - - -static void finish_channel(struct ust_channel *channel) -{ - unsigned int i; - - for (i=0; in_cpus; i++) { - ltt_relay_finish_buffer(channel, i); - } -} - - -/* - * ltt_reserve_switch_old_subbuf: switch old subbuffer - * - * Concurrency safe because we are the last and only thread to alter this - * sub-buffer. As long as it is not delivered and read, no other thread can - * alter the offset, alter the reserve_count or call the - * client_buffer_end_callback on this sub-buffer. - * - * The only remaining threads could be the ones with pending commits. They will - * have to do the deliver themselves. Not concurrency safe in overwrite mode. - * We detect corrupted subbuffers with commit and reserve counts. We keep a - * corrupted sub-buffers count and push the readers across these sub-buffers. - * - * Not concurrency safe if a writer is stalled in a subbuffer and another writer - * switches in, finding out it's corrupted. The result will be than the old - * (uncommited) subbuffer will be declared corrupted, and that the new subbuffer - * will be declared corrupted too because of the commit count adjustment. - * - * Note : offset_old should never be 0 here. - */ -static void ltt_reserve_switch_old_subbuf( - struct ust_channel *chan, struct ust_buffer *buf, - struct ltt_reserve_switch_offsets *offsets, u64 *tsc) -{ - long oldidx = SUBBUF_INDEX(offsets->old - 1, chan); - long commit_count, padding_size; - - padding_size = chan->subbuf_size - - (SUBBUF_OFFSET(offsets->old - 1, chan) + 1); - ltt_buffer_end(buf, *tsc, offsets->old, oldidx); - - /* - * Must write slot data before incrementing commit count. - * This compiler barrier is upgraded into a cmm_smp_wmb() by the IPI - * sent by get_subbuf() when it does its cmm_smp_rmb(). - */ - cmm_smp_wmb(); - uatomic_add(&buf->commit_count[oldidx].cc, padding_size); - commit_count = uatomic_read(&buf->commit_count[oldidx].cc); - ltt_check_deliver(chan, buf, offsets->old - 1, commit_count, oldidx); - ltt_write_commit_counter(chan, buf, oldidx, - offsets->old, commit_count, padding_size); -} - -/* - * ltt_reserve_switch_new_subbuf: Populate new subbuffer. - * - * This code can be executed unordered : writers may already have written to the - * sub-buffer before this code gets executed, caution. The commit makes sure - * that this code is executed before the deliver of this sub-buffer. - */ -static void ltt_reserve_switch_new_subbuf( - struct ust_channel *chan, struct ust_buffer *buf, - struct ltt_reserve_switch_offsets *offsets, u64 *tsc) -{ - long beginidx = SUBBUF_INDEX(offsets->begin, chan); - long commit_count; - - ltt_buffer_begin(buf, *tsc, beginidx); - - /* - * Must write slot data before incrementing commit count. - * This compiler barrier is upgraded into a cmm_smp_wmb() by the IPI - * sent by get_subbuf() when it does its cmm_smp_rmb(). - */ - cmm_smp_wmb(); - uatomic_add(&buf->commit_count[beginidx].cc, ltt_subbuffer_header_size()); - commit_count = uatomic_read(&buf->commit_count[beginidx].cc); - /* Check if the written buffer has to be delivered */ - ltt_check_deliver(chan, buf, offsets->begin, commit_count, beginidx); - ltt_write_commit_counter(chan, buf, beginidx, - offsets->begin, commit_count, ltt_subbuffer_header_size()); -} - -/* - * ltt_reserve_end_switch_current: finish switching current subbuffer - * - * Concurrency safe because we are the last and only thread to alter this - * sub-buffer. As long as it is not delivered and read, no other thread can - * alter the offset, alter the reserve_count or call the - * client_buffer_end_callback on this sub-buffer. - * - * The only remaining threads could be the ones with pending commits. They will - * have to do the deliver themselves. Not concurrency safe in overwrite mode. - * We detect corrupted subbuffers with commit and reserve counts. We keep a - * corrupted sub-buffers count and push the readers across these sub-buffers. - * - * Not concurrency safe if a writer is stalled in a subbuffer and another writer - * switches in, finding out it's corrupted. The result will be than the old - * (uncommited) subbuffer will be declared corrupted, and that the new subbuffer - * will be declared corrupted too because of the commit count adjustment. - */ -static void ltt_reserve_end_switch_current( - struct ust_channel *chan, - struct ust_buffer *buf, - struct ltt_reserve_switch_offsets *offsets, u64 *tsc) -{ - long endidx = SUBBUF_INDEX(offsets->end - 1, chan); - long commit_count, padding_size; - - padding_size = chan->subbuf_size - - (SUBBUF_OFFSET(offsets->end - 1, chan) + 1); - - ltt_buffer_end(buf, *tsc, offsets->end, endidx); - - /* - * Must write slot data before incrementing commit count. - * This compiler barrier is upgraded into a cmm_smp_wmb() by the IPI - * sent by get_subbuf() when it does its cmm_smp_rmb(). - */ - cmm_smp_wmb(); - uatomic_add(&buf->commit_count[endidx].cc, padding_size); - commit_count = uatomic_read(&buf->commit_count[endidx].cc); - ltt_check_deliver(chan, buf, - offsets->end - 1, commit_count, endidx); - ltt_write_commit_counter(chan, buf, endidx, - offsets->end, commit_count, padding_size); -} - -/* - * Returns : - * 0 if ok - * !0 if execution must be aborted. - */ -static int ltt_relay_try_switch_slow( - enum force_switch_mode mode, - struct ust_channel *chan, - struct ust_buffer *buf, - struct ltt_reserve_switch_offsets *offsets, - u64 *tsc) -{ - long subbuf_index; - long reserve_commit_diff; - - offsets->begin = uatomic_read(&buf->offset); - offsets->old = offsets->begin; - offsets->begin_switch = 0; - offsets->end_switch_old = 0; - - *tsc = trace_clock_read64(); - - if (SUBBUF_OFFSET(offsets->begin, buf->chan) != 0) { - offsets->begin = SUBBUF_ALIGN(offsets->begin, buf->chan); - offsets->end_switch_old = 1; - } else { - /* we do not have to switch : buffer is empty */ - return -1; - } - if (mode == FORCE_ACTIVE) - offsets->begin += ltt_subbuffer_header_size(); - /* - * Always begin_switch in FORCE_ACTIVE mode. - * Test new buffer integrity - */ - subbuf_index = SUBBUF_INDEX(offsets->begin, buf->chan); - reserve_commit_diff = - (BUFFER_TRUNC(offsets->begin, buf->chan) - >> chan->n_subbufs_order) - - (uatomic_read(&buf->commit_count[subbuf_index].cc_sb) - & chan->commit_count_mask); - if (reserve_commit_diff == 0) { - /* Next buffer not corrupted. */ - if (mode == FORCE_ACTIVE - && !chan->overwrite - && offsets->begin - uatomic_read(&buf->consumed) - >= chan->alloc_size) { - /* - * We do not overwrite non consumed buffers and we are - * full : ignore switch while tracing is active. - */ - return -1; - } - } else { - /* - * Next subbuffer corrupted. Force pushing reader even in normal - * mode - */ - } - offsets->end = offsets->begin; - return 0; -} - -/* - * Force a sub-buffer switch for a per-cpu buffer. This operation is - * completely reentrant : can be called while tracing is active with - * absolutely no lock held. - */ -void ltt_force_switch_lockless_slow(struct ust_buffer *buf, - enum force_switch_mode mode) -{ - struct ust_channel *chan = buf->chan; - struct ltt_reserve_switch_offsets offsets; - u64 tsc; - - offsets.size = 0; - - DBG("Switching (forced) %s_%d", chan->channel_name, buf->cpu); - /* - * Perform retryable operations. - */ - do { - if (ltt_relay_try_switch_slow(mode, chan, buf, - &offsets, &tsc)) - return; - } while (uatomic_cmpxchg(&buf->offset, offsets.old, - offsets.end) != offsets.old); - - /* - * Atomically update last_tsc. This update races against concurrent - * atomic updates, but the race will always cause supplementary full TSC - * events, never the opposite (missing a full TSC event when it would be - * needed). - */ - save_last_tsc(buf, tsc); - - /* - * Push the reader if necessary - */ - if (mode == FORCE_ACTIVE) { - ltt_reserve_push_reader(chan, buf, offsets.end - 1); - } - - /* - * Switch old subbuffer if needed. - */ - if (offsets.end_switch_old) { - ltt_reserve_switch_old_subbuf(chan, buf, &offsets, &tsc); - } - - /* - * Populate new subbuffer. - */ - if (mode == FORCE_ACTIVE) - ltt_reserve_switch_new_subbuf(chan, buf, &offsets, &tsc); -} - -/* - * Returns : - * 0 if ok - * !0 if execution must be aborted. - */ -static int ltt_relay_try_reserve_slow(struct ust_channel *chan, struct ust_buffer *buf, - struct ltt_reserve_switch_offsets *offsets, size_t data_size, - u64 *tsc, unsigned int *rflags, int largest_align) -{ - long reserve_commit_diff; - - offsets->begin = uatomic_read(&buf->offset); - offsets->old = offsets->begin; - offsets->begin_switch = 0; - offsets->end_switch_current = 0; - offsets->end_switch_old = 0; - - *tsc = trace_clock_read64(); - if (last_tsc_overflow(buf, *tsc)) - *rflags = LTT_RFLAG_ID_SIZE_TSC; - - if (unlikely(SUBBUF_OFFSET(offsets->begin, buf->chan) == 0)) { - offsets->begin_switch = 1; /* For offsets->begin */ - } else { - offsets->size = ust_get_header_size(chan, - offsets->begin, data_size, - &offsets->before_hdr_pad, *rflags); - offsets->size += ltt_align(offsets->begin + offsets->size, - largest_align) - + data_size; - if (unlikely((SUBBUF_OFFSET(offsets->begin, buf->chan) + - offsets->size) > buf->chan->subbuf_size)) { - offsets->end_switch_old = 1; /* For offsets->old */ - offsets->begin_switch = 1; /* For offsets->begin */ - } - } - if (unlikely(offsets->begin_switch)) { - long subbuf_index; - - /* - * We are typically not filling the previous buffer completely. - */ - if (likely(offsets->end_switch_old)) - offsets->begin = SUBBUF_ALIGN(offsets->begin, - buf->chan); - offsets->begin = offsets->begin + ltt_subbuffer_header_size(); - /* Test new buffer integrity */ - subbuf_index = SUBBUF_INDEX(offsets->begin, buf->chan); - reserve_commit_diff = - (BUFFER_TRUNC(offsets->begin, buf->chan) - >> chan->n_subbufs_order) - - (uatomic_read(&buf->commit_count[subbuf_index].cc_sb) - & chan->commit_count_mask); - if (likely(reserve_commit_diff == 0)) { - /* Next buffer not corrupted. */ - if (unlikely(!chan->overwrite && - (SUBBUF_TRUNC(offsets->begin, buf->chan) - - SUBBUF_TRUNC(uatomic_read( - &buf->consumed), - buf->chan)) - >= chan->alloc_size)) { - /* - * We do not overwrite non consumed buffers - * and we are full : event is lost. - */ - uatomic_inc(&buf->events_lost); - return -1; - } else { - /* - * next buffer not corrupted, we are either in - * overwrite mode or the buffer is not full. - * It's safe to write in this new subbuffer. - */ - } - } else { - /* - * Next subbuffer corrupted. Drop event in normal and - * overwrite mode. Caused by either a writer OOPS or - * too many nested writes over a reserve/commit pair. - */ - uatomic_inc(&buf->events_lost); - return -1; - } - offsets->size = ust_get_header_size(chan, - offsets->begin, data_size, - &offsets->before_hdr_pad, *rflags); - offsets->size += ltt_align(offsets->begin + offsets->size, - largest_align) - + data_size; - if (unlikely((SUBBUF_OFFSET(offsets->begin, buf->chan) - + offsets->size) > buf->chan->subbuf_size)) { - /* - * Event too big for subbuffers, report error, don't - * complete the sub-buffer switch. - */ - uatomic_inc(&buf->events_lost); - return -1; - } else { - /* - * We just made a successful buffer switch and the event - * fits in the new subbuffer. Let's write. - */ - } - } else { - /* - * Event fits in the current buffer and we are not on a switch - * boundary. It's safe to write. - */ - } - offsets->end = offsets->begin + offsets->size; - - if (unlikely((SUBBUF_OFFSET(offsets->end, buf->chan)) == 0)) { - /* - * The offset_end will fall at the very beginning of the next - * subbuffer. - */ - offsets->end_switch_current = 1; /* For offsets->begin */ - } - return 0; -} - -/** - * ltt_relay_reserve_slot_lockless_slow - Atomic slot reservation in a buffer. - * @trace: the trace structure to log to. - * @ltt_channel: channel structure - * @transport_data: data structure specific to ltt relay - * @data_size: size of the variable length data to log. - * @slot_size: pointer to total size of the slot (out) - * @buf_offset : pointer to reserved buffer offset (out) - * @tsc: pointer to the tsc at the slot reservation (out) - * @cpu: cpuid - * - * Return : -ENOSPC if not enough space, else returns 0. - * It will take care of sub-buffer switching. - */ -int ltt_reserve_slot_lockless_slow(struct ust_channel *chan, - struct ust_trace *trace, size_t data_size, - int largest_align, int cpu, - struct ust_buffer **ret_buf, - size_t *slot_size, long *buf_offset, - u64 *tsc, unsigned int *rflags) -{ - struct ust_buffer *buf = *ret_buf = chan->buf[cpu]; - struct ltt_reserve_switch_offsets offsets; - - offsets.size = 0; - - do { - if (unlikely(ltt_relay_try_reserve_slow(chan, buf, &offsets, - data_size, tsc, rflags, largest_align))) - return -ENOSPC; - } while (unlikely(uatomic_cmpxchg(&buf->offset, offsets.old, - offsets.end) != offsets.old)); - - /* - * Atomically update last_tsc. This update races against concurrent - * atomic updates, but the race will always cause supplementary full TSC - * events, never the opposite (missing a full TSC event when it would be - * needed). - */ - save_last_tsc(buf, *tsc); - - /* - * Push the reader if necessary - */ - ltt_reserve_push_reader(chan, buf, offsets.end - 1); - - /* - * Switch old subbuffer if needed. - */ - if (unlikely(offsets.end_switch_old)) { - ltt_reserve_switch_old_subbuf(chan, buf, &offsets, tsc); - DBG("Switching %s_%d", chan->channel_name, cpu); - } - - /* - * Populate new subbuffer. - */ - if (unlikely(offsets.begin_switch)) - ltt_reserve_switch_new_subbuf(chan, buf, &offsets, tsc); - - if (unlikely(offsets.end_switch_current)) - ltt_reserve_end_switch_current(chan, buf, &offsets, tsc); - - *slot_size = offsets.size; - *buf_offset = offsets.begin + offsets.before_hdr_pad; - return 0; -} - -static struct ltt_transport ust_relay_transport = { - .name = "ustrelay", - .ops = { - .create_channel = create_channel, - .finish_channel = finish_channel, - .remove_channel = remove_channel, - .wakeup_channel = ltt_relay_async_wakeup_chan, - }, -}; - -static char initialized = 0; - -void __attribute__((constructor)) init_ustrelay_transport(void) -{ - init_usterr(); - if(!initialized) { - ltt_transport_register(&ust_relay_transport); - initialized = 1; - } -} - -static void __attribute__((destructor)) ust_buffers_exit(void) -{ - ltt_transport_unregister(&ust_relay_transport); -} - -size_t ltt_write_event_header_slow(struct ust_channel *channel, - struct ust_buffer *buf, long buf_offset, - u16 eID, u32 event_size, - u64 tsc, unsigned int rflags) -{ - struct ltt_event_header header; - u16 small_size; - - switch (rflags) { - case LTT_RFLAG_ID_SIZE_TSC: - header.id_time = 29 << LTT_TSC_BITS; - break; - case LTT_RFLAG_ID_SIZE: - header.id_time = 30 << LTT_TSC_BITS; - break; - case LTT_RFLAG_ID: - header.id_time = 31 << LTT_TSC_BITS; - break; - default: - WARN_ON_ONCE(1); - header.id_time = 0; - break; - } - - header.id_time |= (u32)tsc & LTT_TSC_MASK; - ust_buffers_write(buf, buf_offset, &header, sizeof(header)); - buf_offset += sizeof(header); - - switch (rflags) { - case LTT_RFLAG_ID_SIZE_TSC: - small_size = (u16)min_t(u32, event_size, LTT_MAX_SMALL_SIZE); - ust_buffers_write(buf, buf_offset, - &eID, sizeof(u16)); - buf_offset += sizeof(u16); - ust_buffers_write(buf, buf_offset, - &small_size, sizeof(u16)); - buf_offset += sizeof(u16); - if (small_size == LTT_MAX_SMALL_SIZE) { - ust_buffers_write(buf, buf_offset, - &event_size, sizeof(u32)); - buf_offset += sizeof(u32); - } - buf_offset += ltt_align(buf_offset, sizeof(u64)); - ust_buffers_write(buf, buf_offset, - &tsc, sizeof(u64)); - buf_offset += sizeof(u64); - break; - case LTT_RFLAG_ID_SIZE: - small_size = (u16)min_t(u32, event_size, LTT_MAX_SMALL_SIZE); - ust_buffers_write(buf, buf_offset, - &eID, sizeof(u16)); - buf_offset += sizeof(u16); - ust_buffers_write(buf, buf_offset, - &small_size, sizeof(u16)); - buf_offset += sizeof(u16); - if (small_size == LTT_MAX_SMALL_SIZE) { - ust_buffers_write(buf, buf_offset, - &event_size, sizeof(u32)); - buf_offset += sizeof(u32); - } - break; - case LTT_RFLAG_ID: - ust_buffers_write(buf, buf_offset, - &eID, sizeof(u16)); - buf_offset += sizeof(u16); - break; - } - - return buf_offset; -} diff --git a/libust/buffers.h b/libust/buffers.h deleted file mode 100644 index a838644..0000000 --- a/libust/buffers.h +++ /dev/null @@ -1,699 +0,0 @@ -/* - * buffers.h - * LTTng userspace tracer buffering system - * - * Copyright (C) 2009 - Pierre-Marc Fournier (pierre-marc dot fournier at polymtl dot ca) - * Copyright (C) 2008 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) - * - * 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; 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 - */ - -#ifndef _UST_BUFFERS_H -#define _UST_BUFFERS_H - -#include - -#include -#include - -#include "usterr_signal_safe.h" -#include "channels.h" -#include "tracerconst.h" -#include "tracercore.h" - -/* - * BUFFER_TRUNC zeroes the subbuffer offset and the subbuffer number parts of - * the offset, which leaves only the buffer number. - */ -#define BUFFER_TRUNC(offset, chan) \ - ((offset) & (~((chan)->alloc_size-1))) -#define BUFFER_OFFSET(offset, chan) ((offset) & ((chan)->alloc_size - 1)) -#define SUBBUF_OFFSET(offset, chan) ((offset) & ((chan)->subbuf_size - 1)) -#define SUBBUF_ALIGN(offset, chan) \ - (((offset) + (chan)->subbuf_size) & (~((chan)->subbuf_size - 1))) -#define SUBBUF_TRUNC(offset, chan) \ - ((offset) & (~((chan)->subbuf_size - 1))) -#define SUBBUF_INDEX(offset, chan) \ - (BUFFER_OFFSET((offset), chan) >> (chan)->subbuf_size_order) - -/* - * Tracks changes to rchan/rchan_buf structs - */ -#define UST_CHANNEL_VERSION 8 - -/**************************************/ - -/* - * TODO: using "long" type for struct ust_buffer (control structure - * shared between traced apps and the consumer) is a very bad idea when - * we get to systems with mixed 32/64-bit processes. - * - * But on 64-bit system, we want the full power of 64-bit counters, - * which wraps less often. Therefore, it's not as easy as "use 32-bit - * types everywhere". - * - * One way to deal with this is to: - * 1) Design 64-bit consumer so it can detect 32-bit and 64-bit apps. - * 2) The 32-bit consumer only supports 32-bit apps. - */ - -struct commit_counters { - long cc; /* ATOMIC */ - long cc_sb; /* ATOMIC - Incremented _once_ at sb switch */ -}; - -struct ust_buffer { - /* First 32 bytes cache-hot cacheline */ - long offset; /* Current offset in the buffer *atomic* */ - struct commit_counters *commit_count; /* Commit count per sub-buffer */ - long consumed; /* Current offset in the buffer *atomic* access (shared) */ - unsigned long last_tsc; /* - * Last timestamp written in the buffer. - */ - /* End of first 32 bytes cacheline */ - long active_readers; /* ATOMIC - Active readers count standard atomic access (shared) */ - long events_lost; /* ATOMIC */ - long corrupted_subbuffers; /* *ATOMIC* */ - /* one byte is written to this pipe when data is available, in order - to wake the consumer */ - /* portability: Single byte writes must be as quick as possible. The kernel-side - buffer must be large enough so the writer doesn't block. From the pipe(7) - man page: Since linux 2.6.11, the pipe capacity is 65536 bytes. */ - int data_ready_fd_write; - /* the reading end of the pipe */ - int data_ready_fd_read; - /* - * List of buffers with an open pipe, used for fork and forced subbuffer - * switch. - */ - struct cds_list_head open_buffers_list; - - unsigned int finalized; -//ust// struct timer_list switch_timer; /* timer for periodical switch */ - unsigned long switch_timer_interval; /* 0 = unset */ - - struct ust_channel *chan; - - struct urcu_ref urcu_ref; - void *buf_data; - size_t buf_size; - int shmid; - unsigned int cpu; - - /* commit count per subbuffer; must be at end of struct */ - long commit_seq[0]; /* ATOMIC */ -} ____cacheline_aligned; - -/* - * A switch is either done during tracing (FORCE_ACTIVE) or as a final - * flush after tracing (with FORCE_FLUSH). FORCE_FLUSH ensures we won't - * write in the new sub-buffer). - */ -enum force_switch_mode { FORCE_ACTIVE, FORCE_FLUSH }; - -extern int ltt_reserve_slot_lockless_slow(struct ust_channel *chan, - struct ust_trace *trace, size_t data_size, - int largest_align, int cpu, - struct ust_buffer **ret_buf, - size_t *slot_size, long *buf_offset, - u64 *tsc, unsigned int *rflags); - -extern void ltt_force_switch_lockless_slow(struct ust_buffer *buf, - enum force_switch_mode mode); - -#ifndef HAVE_EFFICIENT_UNALIGNED_ACCESS - -/* - * Calculate the offset needed to align the type. - * size_of_type must be non-zero. - */ -static inline unsigned int ltt_align(size_t align_drift, size_t size_of_type) -{ - size_t alignment = min(sizeof(void *), size_of_type); - return (alignment - align_drift) & (alignment - 1); -} -/* Default arch alignment */ -#define LTT_ALIGN - -static inline int ltt_get_alignment(void) -{ - return sizeof(void *); -} - -#else /* HAVE_EFFICIENT_UNALIGNED_ACCESS */ - -static inline unsigned int ltt_align(size_t align_drift, - size_t size_of_type) -{ - return 0; -} - -#define LTT_ALIGN __attribute__((packed)) - -static inline int ltt_get_alignment(void) -{ - return 0; -} -#endif /* HAVE_EFFICIENT_UNALIGNED_ACCESS */ - -static __inline__ void ust_buffers_do_copy(void *dest, const void *src, size_t len) -{ - union { - const void *src; - const u8 *src8; - const u16 *src16; - const u32 *src32; - const u64 *src64; - } u = { .src = src }; - - switch (len) { - case 0: break; - case 1: *(u8 *)dest = *u.src8; - break; - case 2: *(u16 *)dest = *u.src16; - break; - case 4: *(u32 *)dest = *u.src32; - break; - case 8: *(u64 *)dest = *u.src64; - break; - default: - memcpy(dest, src, len); - } -} - -static __inline__ void *ust_buffers_offset_address(struct ust_buffer *buf, size_t offset) -{ - return ((char *)buf->buf_data)+offset; -} - -/* - * Last TSC comparison functions. Check if the current TSC overflows - * LTT_TSC_BITS bits from the last TSC read. Reads and writes last_tsc - * atomically. - */ - -/* FIXME: does this test work properly? */ -#if (BITS_PER_LONG == 32) -static __inline__ void save_last_tsc(struct ust_buffer *ltt_buf, - u64 tsc) -{ - ltt_buf->last_tsc = (unsigned long)(tsc >> LTT_TSC_BITS); -} - -static __inline__ int last_tsc_overflow(struct ust_buffer *ltt_buf, - u64 tsc) -{ - unsigned long tsc_shifted = (unsigned long)(tsc >> LTT_TSC_BITS); - - if (unlikely((tsc_shifted - ltt_buf->last_tsc))) - return 1; - else - return 0; -} -#else -static __inline__ void save_last_tsc(struct ust_buffer *ltt_buf, - u64 tsc) -{ - ltt_buf->last_tsc = (unsigned long)tsc; -} - -static __inline__ int last_tsc_overflow(struct ust_buffer *ltt_buf, - u64 tsc) -{ - if (unlikely((tsc - ltt_buf->last_tsc) >> LTT_TSC_BITS)) - return 1; - else - return 0; -} -#endif - -/* - * ust_get_header_size - * - * Calculate alignment offset to 32-bits. This is the alignment offset of the - * event header. - * - * Important note : - * The event header must be 32-bits. The total offset calculated here : - * - * Alignment of header struct on 32 bits (min arch size, header size) - * + sizeof(header struct) (32-bits) - * + (opt) u16 (ext. event id) - * + (opt) u16 (event_size) (if event_size == 0xFFFFUL, has ext. event size) - * + (opt) u32 (ext. event size) - * + (opt) u64 full TSC (aligned on min(64-bits, arch size)) - * - * The payload must itself determine its own alignment from the biggest type it - * contains. - * */ -static __inline__ unsigned char ust_get_header_size( - struct ust_channel *channel, - size_t offset, - size_t data_size, - size_t *before_hdr_pad, - unsigned int rflags) -{ - size_t orig_offset = offset; - size_t padding; - - padding = ltt_align(offset, sizeof(struct ltt_event_header)); - offset += padding; - offset += sizeof(struct ltt_event_header); - - if(unlikely(rflags)) { - switch (rflags) { - case LTT_RFLAG_ID_SIZE_TSC: - offset += sizeof(u16) + sizeof(u16); - if (data_size >= 0xFFFFU) - offset += sizeof(u32); - offset += ltt_align(offset, sizeof(u64)); - offset += sizeof(u64); - break; - case LTT_RFLAG_ID_SIZE: - offset += sizeof(u16) + sizeof(u16); - if (data_size >= 0xFFFFU) - offset += sizeof(u32); - break; - case LTT_RFLAG_ID: - offset += sizeof(u16); - break; - } - } - - *before_hdr_pad = padding; - return offset - orig_offset; -} - -static __inline__ void ltt_reserve_push_reader( - struct ust_channel *rchan, - struct ust_buffer *buf, - long offset) -{ - long consumed_old, consumed_new; - - do { - consumed_old = uatomic_read(&buf->consumed); - /* - * If buffer is in overwrite mode, push the reader consumed - * count if the write position has reached it and we are not - * at the first iteration (don't push the reader farther than - * the writer). This operation can be done concurrently by many - * writers in the same buffer, the writer being at the farthest - * write position sub-buffer index in the buffer being the one - * which will win this loop. - * If the buffer is not in overwrite mode, pushing the reader - * only happens if a sub-buffer is corrupted. - */ - if (unlikely((SUBBUF_TRUNC(offset, buf->chan) - - SUBBUF_TRUNC(consumed_old, buf->chan)) - >= rchan->alloc_size)) - consumed_new = SUBBUF_ALIGN(consumed_old, buf->chan); - else - return; - } while (unlikely(uatomic_cmpxchg(&buf->consumed, consumed_old, - consumed_new) != consumed_old)); -} - -static __inline__ void ltt_vmcore_check_deliver( - struct ust_buffer *buf, - long commit_count, long idx) -{ - uatomic_set(&buf->commit_seq[idx], commit_count); -} - -static __inline__ void ltt_check_deliver(struct ust_channel *chan, - struct ust_buffer *buf, - long offset, long commit_count, long idx) -{ - long old_commit_count = commit_count - chan->subbuf_size; - - /* Check if all commits have been done */ - if (unlikely((BUFFER_TRUNC(offset, chan) - >> chan->n_subbufs_order) - - (old_commit_count - & chan->commit_count_mask) == 0)) { - /* - * If we succeeded in updating the cc_sb, we are delivering - * the subbuffer. Deals with concurrent updates of the "cc" - * value without adding a add_return atomic operation to the - * fast path. - */ - if (likely(uatomic_cmpxchg(&buf->commit_count[idx].cc_sb, - old_commit_count, commit_count) - == old_commit_count)) { - int result; - - /* - * Set noref flag for this subbuffer. - */ -//ust// ltt_set_noref_flag(rchan, buf, idx); - ltt_vmcore_check_deliver(buf, commit_count, idx); - - /* wakeup consumer */ - result = write(buf->data_ready_fd_write, "1", 1); - if(result == -1) { - PERROR("write (in ltt_relay_buffer_flush)"); - ERR("this should never happen!"); - } - } - } -} - -static __inline__ int ltt_poll_deliver(struct ust_channel *chan, struct ust_buffer *buf) -{ - long consumed_old, consumed_idx, commit_count, write_offset; - - consumed_old = uatomic_read(&buf->consumed); - consumed_idx = SUBBUF_INDEX(consumed_old, buf->chan); - commit_count = uatomic_read(&buf->commit_count[consumed_idx].cc_sb); - /* - * No memory cmm_barrier here, since we are only interested - * in a statistically correct polling result. The next poll will - * get the data is we are racing. The mb() that ensures correct - * memory order is in get_subbuf. - */ - write_offset = uatomic_read(&buf->offset); - - /* - * Check that the subbuffer we are trying to consume has been - * already fully committed. - */ - - if (((commit_count - chan->subbuf_size) - & chan->commit_count_mask) - - (BUFFER_TRUNC(consumed_old, buf->chan) - >> chan->n_subbufs_order) - != 0) - return 0; - - /* - * Check that we are not about to read the same subbuffer in - * which the writer head is. - */ - if ((SUBBUF_TRUNC(write_offset, buf->chan) - - SUBBUF_TRUNC(consumed_old, buf->chan)) - == 0) - return 0; - - return 1; - -} - -/* - * returns 0 if reserve ok, or 1 if the slow path must be taken. - */ -static __inline__ int ltt_relay_try_reserve( - struct ust_channel *chan, - struct ust_buffer *buf, - size_t data_size, - u64 *tsc, unsigned int *rflags, int largest_align, - long *o_begin, long *o_end, long *o_old, - size_t *before_hdr_pad, size_t *size) -{ - *o_begin = uatomic_read(&buf->offset); - *o_old = *o_begin; - - *tsc = trace_clock_read64(); - - if (last_tsc_overflow(buf, *tsc)) - *rflags = LTT_RFLAG_ID_SIZE_TSC; - - if (unlikely(SUBBUF_OFFSET(*o_begin, buf->chan) == 0)) - return 1; - - *size = ust_get_header_size(chan, - *o_begin, data_size, - before_hdr_pad, *rflags); - *size += ltt_align(*o_begin + *size, largest_align) + data_size; - if (unlikely((SUBBUF_OFFSET(*o_begin, buf->chan) + *size) - > buf->chan->subbuf_size)) - return 1; - - /* - * Event fits in the current buffer and we are not on a switch - * boundary. It's safe to write. - */ - *o_end = *o_begin + *size; - - if (unlikely((SUBBUF_OFFSET(*o_end, buf->chan)) == 0)) - /* - * The offset_end will fall at the very beginning of the next - * subbuffer. - */ - return 1; - - return 0; -} - -static __inline__ int ltt_reserve_slot(struct ust_channel *chan, - struct ust_trace *trace, size_t data_size, - int largest_align, int cpu, - struct ust_buffer **ret_buf, - size_t *slot_size, long *buf_offset, u64 *tsc, - unsigned int *rflags) -{ - struct ust_buffer *buf = *ret_buf = chan->buf[cpu]; - long o_begin, o_end, o_old; - size_t before_hdr_pad; - - /* - * Perform retryable operations. - */ - if (unlikely(CMM_LOAD_SHARED(ltt_nesting) > 4)) { - DBG("Dropping event because nesting is too deep."); - uatomic_inc(&buf->events_lost); - return -EPERM; - } - - if (unlikely(ltt_relay_try_reserve(chan, buf, - data_size, tsc, rflags, - largest_align, &o_begin, &o_end, &o_old, - &before_hdr_pad, slot_size))) - goto slow_path; - - if (unlikely(uatomic_cmpxchg(&buf->offset, o_old, o_end) != o_old)) - goto slow_path; - - /* - * Atomically update last_tsc. This update races against concurrent - * atomic updates, but the race will always cause supplementary full TSC - * events, never the opposite (missing a full TSC event when it would be - * needed). - */ - save_last_tsc(buf, *tsc); - - /* - * Push the reader if necessary - */ - ltt_reserve_push_reader(chan, buf, o_end - 1); - - *buf_offset = o_begin + before_hdr_pad; - return 0; -slow_path: - return ltt_reserve_slot_lockless_slow(chan, trace, data_size, - largest_align, cpu, ret_buf, - slot_size, buf_offset, tsc, - rflags); -} - -/* - * Force a sub-buffer switch for a per-cpu buffer. This operation is - * completely reentrant : can be called while tracing is active with - * absolutely no lock held. - */ -static __inline__ void ltt_force_switch(struct ust_buffer *buf, - enum force_switch_mode mode) -{ - return ltt_force_switch_lockless_slow(buf, mode); -} - -/* - * for flight recording. must be called after relay_commit. - * This function increments the subbuffers's commit_seq counter each time the - * commit count reaches back the reserve offset (module subbuffer size). It is - * useful for crash dump. - */ -static __inline__ void ltt_write_commit_counter(struct ust_channel *chan, - struct ust_buffer *buf, long idx, long buf_offset, - long commit_count, size_t data_size) -{ - long offset; - long commit_seq_old; - - offset = buf_offset + data_size; - - /* - * SUBBUF_OFFSET includes commit_count_mask. We can simply - * compare the offsets within the subbuffer without caring about - * buffer full/empty mismatch because offset is never zero here - * (subbuffer header and event headers have non-zero length). - */ - if (unlikely(SUBBUF_OFFSET(offset - commit_count, buf->chan))) - return; - - commit_seq_old = uatomic_read(&buf->commit_seq[idx]); - while (commit_seq_old < commit_count) - commit_seq_old = uatomic_cmpxchg(&buf->commit_seq[idx], - commit_seq_old, commit_count); - - DBG("commit_seq for channel %s_%d, subbuf %ld is now %ld", buf->chan->channel_name, buf->cpu, idx, commit_count); -} - -/* - * Atomic unordered slot commit. Increments the commit count in the - * specified sub-buffer, and delivers it if necessary. - * - * Parameters: - * - * @ltt_channel : channel structure - * @transport_data: transport-specific data - * @buf_offset : offset following the event header. - * @data_size : size of the event data. - * @slot_size : size of the reserved slot. - */ -static __inline__ void ltt_commit_slot( - struct ust_channel *chan, - struct ust_buffer *buf, long buf_offset, - size_t data_size, size_t slot_size) -{ - long offset_end = buf_offset; - long endidx = SUBBUF_INDEX(offset_end - 1, chan); - long commit_count; - - cmm_smp_wmb(); - - uatomic_add(&buf->commit_count[endidx].cc, slot_size); - /* - * commit count read can race with concurrent OOO commit count updates. - * This is only needed for ltt_check_deliver (for non-polling delivery - * only) and for ltt_write_commit_counter. The race can only cause the - * counter to be read with the same value more than once, which could - * cause : - * - Multiple delivery for the same sub-buffer (which is handled - * gracefully by the reader code) if the value is for a full - * sub-buffer. It's important that we can never miss a sub-buffer - * delivery. Re-reading the value after the uatomic_add ensures this. - * - Reading a commit_count with a higher value that what was actually - * added to it for the ltt_write_commit_counter call (again caused by - * a concurrent committer). It does not matter, because this function - * is interested in the fact that the commit count reaches back the - * reserve offset for a specific sub-buffer, which is completely - * independent of the order. - */ - commit_count = uatomic_read(&buf->commit_count[endidx].cc); - - ltt_check_deliver(chan, buf, offset_end - 1, commit_count, endidx); - /* - * Update data_size for each commit. It's needed only for extracting - * ltt buffers from vmcore, after crash. - */ - ltt_write_commit_counter(chan, buf, endidx, buf_offset, commit_count, data_size); -} - -void _ust_buffers_strncpy_fixup(struct ust_buffer *buf, size_t offset, - size_t len, size_t copied, int terminated); - -static __inline__ int ust_buffers_write(struct ust_buffer *buf, size_t offset, - const void *src, size_t len) -{ - size_t buf_offset = BUFFER_OFFSET(offset, buf->chan); - - assert(buf_offset < buf->chan->subbuf_size*buf->chan->subbuf_cnt); - assert(buf_offset + len - <= buf->chan->subbuf_size*buf->chan->subbuf_cnt); - - ust_buffers_do_copy(buf->buf_data + buf_offset, src, len); - - return len; -} - -/* - * ust_buffers_do_memset - write character into dest. - * @dest: destination - * @src: source character - * @len: length to write - */ -static __inline__ -void ust_buffers_do_memset(void *dest, char src, size_t len) -{ - /* - * What we really want here is an __inline__ memset, but we - * don't have constants, so gcc generally uses a function call. - */ - for (; len > 0; len--) - *(u8 *)dest++ = src; -} - -/* - * ust_buffers_do_strncpy - copy a string up to a certain number of bytes - * @dest: destination - * @src: source - * @len: max. length to copy - * @terminated: output string ends with \0 (output) - * - * returns the number of bytes copied. Does not finalize with \0 if len is - * reached. - */ -static __inline__ -size_t ust_buffers_do_strncpy(void *dest, const void *src, size_t len, - int *terminated) -{ - size_t orig_len = len; - - *terminated = 0; - /* - * What we really want here is an __inline__ strncpy, but we - * don't have constants, so gcc generally uses a function call. - */ - for (; len > 0; len--) { - *(u8 *)dest = CMM_LOAD_SHARED(*(const u8 *)src); - /* Check with dest, because src may be modified concurrently */ - if (*(const u8 *)dest == '\0') { - len--; - *terminated = 1; - break; - } - dest++; - src++; - } - return orig_len - len; -} - -static __inline__ -int ust_buffers_strncpy(struct ust_buffer *buf, size_t offset, const void *src, - size_t len) -{ - size_t buf_offset = BUFFER_OFFSET(offset, buf->chan); - ssize_t copied; - int terminated; - - assert(buf_offset < buf->chan->subbuf_size*buf->chan->subbuf_cnt); - assert(buf_offset + len - <= buf->chan->subbuf_size*buf->chan->subbuf_cnt); - - copied = ust_buffers_do_strncpy(buf->buf_data + buf_offset, - src, len, &terminated); - if (unlikely(copied < len || !terminated)) - _ust_buffers_strncpy_fixup(buf, offset, len, copied, - terminated); - return len; -} - -extern int ust_buffers_get_subbuf(struct ust_buffer *buf, long *consumed); -extern int ust_buffers_put_subbuf(struct ust_buffer *buf, unsigned long uconsumed_old); - -extern void init_ustrelay_transport(void); - -#endif /* _UST_BUFFERS_H */