* 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)
+ * 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
* 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 <unistd.h>
#include <sys/mman.h>
#include <sys/ipc.h>
#include "channels.h"
#include "tracer.h"
#include "tracercore.h"
-#include "usterr.h"
+#include "usterr_signal_safe.h"
struct ltt_reserve_switch_offsets {
long begin, end, old;
static DEFINE_MUTEX(ust_buffers_channels_mutex);
-static LIST_HEAD(ust_buffers_channels);
+static CDS_LIST_HEAD(ust_buffers_channels);
+
+static void ltt_force_switch(struct ust_buffer *buf,
+ enum force_switch_mode mode);
static int get_n_cpus(void)
{
return n_cpus;
}
-/* _ust_buffers_write()
+/**
+ * _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
*
- * @buf: destination buffer
- * @offset: offset in destination
- * @src: source buffer
- * @len: length of source
- * @cpy: already copied
+ * Fills string with "X" if incomplete.
*/
-
-void _ust_buffers_write(struct ust_buffer *buf, size_t offset,
- const void *src, size_t len, ssize_t cpy)
+void _ust_buffers_strncpy_fixup(struct ust_buffer *buf, size_t offset,
+ size_t len, size_t copied, int terminated)
{
- do {
- len -= cpy;
- src += cpy;
- offset += cpy;
+ size_t buf_offset, cpy;
- WARN_ON(offset >= buf->buf_size);
+ 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;
+ }
- cpy = min_t(size_t, len, buf->buf_size - offset);
- ust_buffers_do_copy(buf->buf_data + offset, src, cpy);
- } while (unlikely(len != cpy));
+ /*
+ * 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 int ust_buffers_init_buffer(struct ust_trace *trace,
- struct ust_channel *ltt_chan,
- struct ust_buffer *buf,
- unsigned int n_subbufs);
+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 ust_buffers_alloc_buf(struct ust_buffer *buf, size_t *size)
+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 == -1 && errno == EINVAL) {
+ if (result < 0 && errno == EINVAL) {
ERR("shmget() returned EINVAL; maybe /proc/sys/kernel/shmmax should be increased.");
return -1;
- }
- else if(result == -1) {
+ } else if (result < 0) {
PERROR("shmget");
return -1;
}
- /* FIXME: should have matching call to shmdt */
ptr = shmat(buf->shmid, NULL, 0);
- if(ptr == (void *) -1) {
+ if (ptr == (void *) -1) {
perror("shmat");
goto destroy_shmem;
}
return 0;
- destroy_shmem:
+destroy_shmem:
result = shmctl(buf->shmid, IPC_RMID, NULL);
if(result == -1) {
perror("shmctl");
return -1;
}
-int ust_buffers_create_buf(struct ust_channel *channel, int cpu)
+static int open_buf(struct ust_channel *chan, int cpu)
{
- int result;
- struct ust_buffer *buf = channel->buf[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;
- buf->cpu = cpu;
- result = ust_buffers_alloc_buf(buf, &channel->alloc_size);
- if(result)
+
+ result = map_buf_data(buf, &chan->alloc_size);
+ if (result < 0)
return -1;
- buf->chan = channel;
- kref_get(&channel->kref);
- return 0;
-}
+ buf->commit_count =
+ zmalloc(sizeof(*buf->commit_count) * n_subbufs);
+ if (!buf->commit_count)
+ goto unmap_buf;
-static void ust_buffers_destroy_channel(struct kref *kref)
-{
- struct ust_channel *chan = container_of(kref, struct ust_channel, kref);
- free(chan);
-}
+ 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];
-static void ust_buffers_destroy_buf(struct ust_buffer *buf)
-{
- struct ust_channel *chan = buf->chan;
- int result;
+ buf->cpu = cpu;
+ buf->chan = chan;
- result = munmap(buf->buf_data, buf->buf_size);
- if(result == -1) {
- PERROR("munmap");
+ 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);
}
-//ust// chan->buf[buf->cpu] = NULL;
- free(buf);
- kref_put(&chan->kref, ust_buffers_destroy_channel);
-}
+ ltt_buffer_begin(buf, trace->start_tsc, 0);
-/* called from kref_put */
-static void ust_buffers_remove_buf(struct kref *kref)
-{
- struct ust_buffer *buf = container_of(kref, struct ust_buffer, kref);
- ust_buffers_destroy_buf(buf);
-}
+ uatomic_add(&buf->commit_count[0].cc, ltt_subbuffer_header_size());
-int ust_buffers_open_buf(struct ust_channel *chan, int cpu)
-{
- int result;
+ uatomic_set(&buf->events_lost, 0);
+ uatomic_set(&buf->corrupted_subbuffers, 0);
- result = ust_buffers_create_buf(chan, cpu);
- if (result == -1)
- return -1;
+ memset(buf->commit_seq, 0, sizeof(buf->commit_seq[0]) * n_subbufs);
- kref_init(&chan->buf[cpu]->kref);
+ return 0;
- result = ust_buffers_init_buffer(chan->trace, chan, chan->buf[cpu], chan->subbuf_cnt);
- if(result == -1)
- return -1;
+free_commit_count:
+ free(buf->commit_count);
- return 0;
+unmap_buf:
+ if (shmdt(buf->buf_data) < 0) {
+ PERROR("shmdt failed");
+ }
- /* FIXME: decrementally destroy on error? */
+ return -1;
}
-/**
- * ust_buffers_close_buf - close a channel buffer
- * @buf: buffer
- */
-static void ust_buffers_close_buf(struct ust_buffer *buf)
+static void close_buf(struct ust_buffer *buf)
{
- kref_put(&buf->kref, ust_buffers_remove_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");
+ }
}
-int ust_buffers_channel_open(struct ust_channel *chan, size_t subbuf_size, size_t subbuf_cnt)
+
+static int open_channel(struct ust_channel *chan, size_t subbuf_size,
+ size_t subbuf_cnt)
{
int i;
int result;
chan->subbuf_size_order = get_count_order(subbuf_size);
chan->alloc_size = subbuf_size * subbuf_cnt;
- kref_init(&chan->kref);
-
pthread_mutex_lock(&ust_buffers_channels_mutex);
- for(i=0; i<chan->n_cpus; i++) {
- result = ust_buffers_open_buf(chan, i);
+ for (i=0; i < chan->n_cpus; i++) {
+ result = open_buf(chan, i);
if (result == -1)
goto error;
}
- list_add(&chan->list, &ust_buffers_channels);
+ cds_list_add(&chan->list, &ust_buffers_channels);
pthread_mutex_unlock(&ust_buffers_channels_mutex);
return 0;
- /* Jump directly inside the loop to close the buffers that were already
- * opened. */
- for(; i>=0; i--) {
- ust_buffers_close_buf(chan->buf[i]);
+ /* Error handling */
error:
- do {} while(0);
- }
+ for(i--; i >= 0; i--)
+ close_buf(chan->buf[i]);
- kref_put(&chan->kref, ust_buffers_destroy_channel);
pthread_mutex_unlock(&ust_buffers_channels_mutex);
return -1;
}
-void ust_buffers_channel_close(struct ust_channel *chan)
+static void close_channel(struct ust_channel *chan)
{
int i;
if(!chan)
return;
pthread_mutex_lock(&ust_buffers_channels_mutex);
- for(i=0; i<chan->n_cpus; i++) {
- /* FIXME: if we make it here, then all buffers were necessarily allocated. Moreover, we don't
- * initialize to NULL so we cannot use this check. Should we? */
-//ust// if (chan->buf[i])
- ust_buffers_close_buf(chan->buf[i]);
+ /*
+ * 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; i<chan->n_cpus; i++) {
+ if (chan->buf[i])
+ close_buf(chan->buf[i]);
}
- list_del(&chan->list);
- kref_put(&chan->kref, ust_buffers_destroy_channel);
- pthread_mutex_unlock(&ust_buffers_channels_mutex);
-}
-
-/*
- * -------
- */
+ cds_list_del(&chan->list);
-static void ust_buffers_destroy_buffer(struct ust_channel *ltt_chan, int cpu);
-
-static void ltt_force_switch(struct ust_buffer *buf,
- enum force_switch_mode mode);
-
-/*
- * Trace callbacks
- */
-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 */
- /* FIXME: add memory barrier? */
- ltt_write_trace_header(channel->trace, header);
+ pthread_mutex_unlock(&ust_buffers_channels_mutex);
}
/*
subbuf_idx * buf->chan->subbuf_size);
u32 data_size = SUBBUF_OFFSET(offset - 1, buf->chan) + 1;
- header->data_size = data_size;
header->sb_size = PAGE_ALIGN(data_size);
header->cycle_count_end = tsc;
header->events_lost = uatomic_read(&buf->events_lost);
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;
}
/*
}
/*
- * Promote compiler barrier to a smp_mb().
+ * 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.
* data and the write offset. Correct consumed offset ordering
* wrt commit count is insured by the use of cmpxchg to update
* the consumed offset.
- * smp_call_function_single can fail if the remote CPU is offline,
- * this is OK because then there is no wmb to execute there.
- * If our thread is executing on the same CPU as the on the buffers
- * belongs to, we don't have to synchronize it at all. If we are
- * migrated, the scheduler will take care of the memory barriers.
- * Normally, smp_call_function_single() should ensure program order when
- * executing the remote function, which implies that it surrounds the
- * function execution with :
- * smp_mb()
- * send IPI
- * csd_lock_wait
- * recv IPI
- * smp_mb()
- * exec. function
- * smp_mb()
- * csd unlock
- * smp_mb()
- *
- * However, smp_call_function_single() does not seem to clearly execute
- * such barriers. It depends on spinlock semantic to provide the barrier
- * before executing the IPI and, when busy-looping, csd_lock_wait only
- * executes smp_mb() when it has to wait for the other CPU.
- *
- * I don't trust this code. Therefore, let's add the smp_mb() sequence
- * required ourself, even if duplicated. It has no performance impact
- * anyway.
- *
- * smp_mb() is needed because smp_rmb() and smp_wmb() only order read vs
- * read and write vs write. They do not ensure core synchronization. We
- * really have to ensure total order between the 3 barriers running on
- * the 2 CPUs.
*/
-//ust// #ifdef LTT_NO_IPI_BARRIER
+
/*
* Local rmb to match the remote wmb to read the commit count before the
* buffer data and the write offset.
*/
- smp_rmb();
-//ust// #else
-//ust// if (raw_smp_processor_id() != buf->cpu) {
-//ust// smp_mb(); /* Total order with IPI handler smp_mb() */
-//ust// smp_call_function_single(buf->cpu, remote_mb, NULL, 1);
-//ust// smp_mb(); /* Total order with IPI handler smp_mb() */
-//ust// }
-//ust// #endif
+ cmm_smp_rmb();
write_offset = uatomic_read(&buf->offset);
/*
== 0) {
return -EAGAIN;
}
-
- /* FIXME: is this ok to disable the reading feature? */
-//ust// retval = update_read_sb_index(buf, consumed_idx);
-//ust// if (retval)
-//ust// return retval;
-
*consumed = consumed_old;
return 0;
consumed_old = consumed_old | uconsumed_old;
consumed_new = SUBBUF_ALIGN(consumed_old, buf->chan);
-//ust// spin_lock(<t_buf->full_lock);
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. */
-//ust// spin_unlock(<t_buf->full_lock);
return -EIO;
} else {
/* tell the client that buffer is now unfull */
index = SUBBUF_INDEX(consumed_old, buf->chan);
data = BUFFER_OFFSET(consumed_old, buf->chan);
ltt_buf_unfull(buf, index, data);
-//ust// spin_unlock(<t_buf->full_lock);
- }
- return 0;
-}
-
-static void ltt_relay_print_subbuffer_errors(
- struct ust_channel *channel,
- long cons_off, int cpu)
-{
- struct ust_buffer *ltt_buf = channel->buf[cpu];
- long cons_idx, commit_count, commit_count_sb, write_offset;
-
- cons_idx = SUBBUF_INDEX(cons_off, channel);
- commit_count = uatomic_read(<t_buf->commit_count[cons_idx].cc);
- commit_count_sb = uatomic_read(<t_buf->commit_count[cons_idx].cc_sb);
-
- /*
- * No need to order commit_count and write_offset reads because we
- * execute after trace is stopped when there are no readers left.
- */
- write_offset = uatomic_read(<t_buf->offset);
- WARN( "LTT : unread channel %s offset is %ld "
- "and cons_off : %ld (cpu %d)\n",
- channel->channel_name, write_offset, cons_off, cpu);
- /* Check each sub-buffer for non filled commit count */
- if (((commit_count - channel->subbuf_size) & channel->commit_count_mask)
- - (BUFFER_TRUNC(cons_off, channel) >> channel->n_subbufs_order) != 0) {
- ERR("LTT : %s : subbuffer %lu has non filled "
- "commit count [cc, cc_sb] [%lu,%lu].\n",
- channel->channel_name, cons_idx, commit_count, commit_count_sb);
- }
- ERR("LTT : %s : commit count : %lu, subbuf size %zd\n",
- channel->channel_name, commit_count,
- channel->subbuf_size);
-}
-
-static void ltt_relay_print_errors(struct ust_trace *trace,
- struct ust_channel *channel, int cpu)
-{
- struct ust_buffer *ltt_buf = channel->buf[cpu];
- long cons_off;
-
- /*
- * Can be called in the error path of allocation when
- * trans_channel_data is not yet set.
- */
- if (!channel)
- return;
-
-//ust// for (cons_off = 0; cons_off < rchan->alloc_size;
-//ust// cons_off = SUBBUF_ALIGN(cons_off, rchan))
-//ust// ust_buffers_print_written(ltt_chan, cons_off, cpu);
- for (cons_off = uatomic_read(<t_buf->consumed);
- (SUBBUF_TRUNC(uatomic_read(<t_buf->offset),
- channel)
- - cons_off) > 0;
- cons_off = SUBBUF_ALIGN(cons_off, channel))
- ltt_relay_print_subbuffer_errors(channel, cons_off, cpu);
-}
-
-static void ltt_relay_print_buffer_errors(struct ust_channel *channel, int cpu)
-{
- struct ust_trace *trace = channel->trace;
- struct ust_buffer *ltt_buf = channel->buf[cpu];
-
- if (uatomic_read(<t_buf->events_lost))
- ERR("channel %s: %ld events lost (cpu %d)",
- channel->channel_name,
- uatomic_read(<t_buf->events_lost), cpu);
- if (uatomic_read(<t_buf->corrupted_subbuffers))
- ERR("channel %s : %ld corrupted subbuffers (cpu %d)",
- channel->channel_name,
- uatomic_read(<t_buf->corrupted_subbuffers), cpu);
-
- ltt_relay_print_errors(trace, channel, cpu);
-}
-
-static void ltt_relay_release_channel(struct kref *kref)
-{
- struct ust_channel *ltt_chan = container_of(kref,
- struct ust_channel, kref);
- free(ltt_chan->buf);
-}
-
-/*
- * Create ltt buffer.
- */
-//ust// static int ltt_relay_create_buffer(struct ust_trace *trace,
-//ust// struct ltt_channel_struct *ltt_chan, struct rchan_buf *buf,
-//ust// unsigned int cpu, unsigned int n_subbufs)
-//ust// {
-//ust// struct ltt_channel_buf_struct *ltt_buf =
-//ust// percpu_ptr(ltt_chan->buf, cpu);
-//ust// unsigned int j;
-//ust//
-//ust// ltt_buf->commit_count =
-//ust// kzalloc_node(sizeof(ltt_buf->commit_count) * n_subbufs,
-//ust// GFP_KERNEL, cpu_to_node(cpu));
-//ust// if (!ltt_buf->commit_count)
-//ust// return -ENOMEM;
-//ust// kref_get(&trace->kref);
-//ust// kref_get(&trace->ltt_transport_kref);
-//ust// kref_get(<t_chan->kref);
-//ust// uatomic_set(<t_buf->offset, ltt_subbuffer_header_size());
-//ust// uatomic_set(<t_buf->consumed, 0);
-//ust// uatomic_set(<t_buf->active_readers, 0);
-//ust// for (j = 0; j < n_subbufs; j++)
-//ust// uatomic_set(<t_buf->commit_count[j], 0);
-//ust// init_waitqueue_head(<t_buf->write_wait);
-//ust// uatomic_set(<t_buf->wakeup_readers, 0);
-//ust// spin_lock_init(<t_buf->full_lock);
-//ust//
-//ust// ltt_buffer_begin_callback(buf, trace->start_tsc, 0);
-//ust// /* atomic_add made on local variable on data that belongs to
-//ust// * various CPUs : ok because tracing not started (for this cpu). */
-//ust// uatomic_add(<t_buf->commit_count[0], ltt_subbuffer_header_size());
-//ust//
-//ust// uatomic_set(<t_buf->events_lost, 0);
-//ust// uatomic_set(<t_buf->corrupted_subbuffers, 0);
-//ust//
-//ust// return 0;
-//ust// }
-
-static int ust_buffers_init_buffer(struct ust_trace *trace,
- struct ust_channel *ltt_chan, struct ust_buffer *buf,
- unsigned int n_subbufs)
-{
- unsigned int j;
- int fds[2];
- int result;
-
- buf->commit_count =
- zmalloc(sizeof(*buf->commit_count) * n_subbufs);
- if (!buf->commit_count)
- return -ENOMEM;
- kref_get(&trace->kref);
- kref_get(&trace->ltt_transport_kref);
- kref_get(<t_chan->kref);
- 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);
- }
-//ust// init_waitqueue_head(&buf->write_wait);
-//ust// uatomic_set(&buf->wakeup_readers, 0);
-//ust// spin_lock_init(&buf->full_lock);
-
- 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);
-
- result = pipe(fds);
- if(result == -1) {
- PERROR("pipe");
- return -1;
}
- buf->data_ready_fd_read = fds[0];
- buf->data_ready_fd_write = fds[1];
-
-//ust// buf->commit_seq = malloc(sizeof(buf->commit_seq) * n_subbufs);
-//ust// if(!ltt_buf->commit_seq) {
-//ust// return -1;
-//ust// }
- memset(buf->commit_seq, 0, sizeof(buf->commit_seq[0]) * n_subbufs);
-
- /* FIXME: decrementally destroy on error */
-
return 0;
}
-/* FIXME: use this function */
-static void ust_buffers_destroy_buffer(struct ust_channel *ltt_chan, int cpu)
-{
- struct ust_trace *trace = ltt_chan->trace;
- struct ust_buffer *ltt_buf = ltt_chan->buf[cpu];
-
- kref_put(<t_chan->trace->ltt_transport_kref,
- ltt_release_transport);
- ltt_relay_print_buffer_errors(ltt_chan, cpu);
-//ust// free(ltt_buf->commit_seq);
- free(ltt_buf->commit_count);
- ltt_buf->commit_count = NULL;
- kref_put(<t_chan->kref, ltt_relay_release_channel);
- kref_put(&trace->kref, ltt_release_trace);
-//ust// wake_up_interruptible(&trace->kref_wq);
-}
-
-static int ust_buffers_alloc_channel_buf_structs(struct ust_channel *chan)
+static int map_buf_structs(struct ust_channel *chan)
{
void *ptr;
int result;
goto destroy_previous;
}
- /* FIXME: should have matching call to shmdt */
ptr = shmat(chan->buf_struct_shmids[i], NULL, 0);
if(ptr == (void *) -1) {
perror("shmat");
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 ust_buffers_create_channel(const char *trace_name, struct ust_trace *trace,
- const char *channel_name, struct ust_channel *ltt_chan,
+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 result;
+ int i, result;
- kref_init(<t_chan->kref);
+ 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();
- ltt_chan->trace = trace;
- ltt_chan->overwrite = overwrite;
- ltt_chan->n_subbufs_order = get_count_order(n_subbufs);
- ltt_chan->commit_count_mask = (~0UL >> ltt_chan->n_subbufs_order);
- ltt_chan->n_cpus = get_n_cpus();
-//ust// ltt_chan->buf = percpu_alloc_mask(sizeof(struct ltt_channel_buf_struct), GFP_KERNEL, cpu_possible_map);
- ltt_chan->buf = (void *) malloc(ltt_chan->n_cpus * sizeof(void *));
- if(ltt_chan->buf == NULL) {
+ /* 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;
}
- ltt_chan->buf_struct_shmids = (int *) malloc(ltt_chan->n_cpus * sizeof(int));
- if(ltt_chan->buf_struct_shmids == NULL)
+ chan->buf_struct_shmids = (int *) zmalloc(chan->n_cpus * sizeof(int));
+ if(chan->buf_struct_shmids == NULL)
goto free_buf;
- result = ust_buffers_alloc_channel_buf_structs(ltt_chan);
+ result = map_buf_structs(chan);
if(result != 0) {
goto free_buf_struct_shmids;
}
- result = ust_buffers_channel_open(ltt_chan, subbuf_size, n_subbufs);
+ result = open_channel(chan, subbuf_size, n_subbufs);
if (result != 0) {
ERR("Cannot open channel for trace %s", trace_name);
- goto unalloc_buf_structs;
+ goto unmap_buf_structs;
}
return 0;
-unalloc_buf_structs:
- /* FIXME: put a call here to unalloc the buf structs! */
+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(ltt_chan->buf_struct_shmids);
+ free(chan->buf_struct_shmids);
free_buf:
- free(ltt_chan->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)
{
-//ust// unsigned int i;
-//ust// struct rchan *rchan = ltt_channel->trans_channel_data;
-//ust//
-//ust// for_each_possible_cpu(i) {
-//ust// struct ltt_channel_buf_struct *ltt_buf =
-//ust// percpu_ptr(ltt_channel->buf, i);
-//ust//
-//ust// if (uatomic_read(<t_buf->wakeup_readers) == 1) {
-//ust// uatomic_set(<t_buf->wakeup_readers, 0);
-//ust// wake_up_interruptible(&rchan->buf[i]->read_wait);
-//ust// }
-//ust// }
}
static void ltt_relay_finish_buffer(struct ust_channel *channel, unsigned int cpu)
{
-// int result;
-
if (channel->buf[cpu]) {
struct ust_buffer *buf = channel->buf[cpu];
ltt_force_switch(buf, FORCE_FLUSH);
-//ust// ltt_relay_wake_writers(ltt_buf);
+
/* closing the pipe tells the consumer the buffer is finished */
-
- //result = write(ltt_buf->data_ready_fd_write, "D", 1);
- //if(result == -1) {
- // PERROR("write (in ltt_relay_finish_buffer)");
- // ERR("this should never happen!");
- //}
close(buf->data_ready_fd_write);
}
}
-static void ltt_relay_finish_channel(struct ust_channel *channel)
+static void finish_channel(struct ust_channel *channel)
{
unsigned int i;
- for(i=0; i<channel->n_cpus; i++) {
+ for (i=0; i<channel->n_cpus; i++) {
ltt_relay_finish_buffer(channel, i);
}
}
-static void ltt_relay_remove_channel(struct ust_channel *channel)
-{
- ust_buffers_channel_close(channel);
- kref_put(&channel->kref, ltt_relay_release_channel);
-}
/*
* ltt_reserve_switch_old_subbuf: switch old subbuffer
/*
* Must write slot data before incrementing commit count.
- * This compiler barrier is upgraded into a smp_wmb() by the IPI
- * sent by get_subbuf() when it does its smp_rmb().
+ * This compiler barrier is upgraded into a cmm_smp_wmb() by the IPI
+ * sent by get_subbuf() when it does its cmm_smp_rmb().
*/
- barrier();
+ 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);
/*
* Must write slot data before incrementing commit count.
- * This compiler barrier is upgraded into a smp_wmb() by the IPI
- * sent by get_subbuf() when it does its smp_rmb().
+ * This compiler barrier is upgraded into a cmm_smp_wmb() by the IPI
+ * sent by get_subbuf() when it does its cmm_smp_rmb().
*/
- barrier();
+ 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 */
/*
* Must write slot data before incrementing commit count.
- * This compiler barrier is upgraded into a smp_wmb() by the IPI
- * sent by get_subbuf() when it does its smp_rmb().
+ * This compiler barrier is upgraded into a cmm_smp_wmb() by the IPI
+ * sent by get_subbuf() when it does its cmm_smp_rmb().
*/
- barrier();
+ 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,
*/
if (mode == FORCE_ACTIVE) {
ltt_reserve_push_reader(chan, buf, offsets.end - 1);
-//ust// ltt_clear_noref_flag(chan, buf, SUBBUF_INDEX(offsets.end - 1, chan));
}
/*
* Switch old subbuffer if needed.
*/
if (offsets.end_switch_old) {
-//ust// ltt_clear_noref_flag(rchan, buf, SUBBUF_INDEX(offsets.old - 1, rchan));
ltt_reserve_switch_old_subbuf(chan, buf, &offsets, &tsc);
}
*/
ltt_reserve_push_reader(chan, buf, offsets.end - 1);
- /*
- * Clear noref flag for this subbuffer.
- */
-//ust// ltt_clear_noref_flag(chan, buf, SUBBUF_INDEX(offsets.end - 1, chan));
-
/*
* Switch old subbuffer if needed.
*/
if (unlikely(offsets.end_switch_old)) {
-//ust// ltt_clear_noref_flag(chan, buf, SUBBUF_INDEX(offsets.old - 1, chan));
ltt_reserve_switch_old_subbuf(chan, buf, &offsets, tsc);
DBG("Switching %s_%d", chan->channel_name, cpu);
}
static struct ltt_transport ust_relay_transport = {
.name = "ustrelay",
.ops = {
- .create_channel = ust_buffers_create_channel,
- .finish_channel = ltt_relay_finish_channel,
- .remove_channel = ltt_relay_remove_channel,
+ .create_channel = create_channel,
+ .finish_channel = finish_channel,
+ .remove_channel = remove_channel,
.wakeup_channel = ltt_relay_async_wakeup_chan,
},
};
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;
projects / ust.git / blobdiff