/*
* 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; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * 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
#include "header-inline.h"
#include <usterr.h>
-/***** SHOULD BE REMOVED ***** */
+/***** FIXME: SHOULD BE REMOVED ***** */
/*
* BUFFER_TRUNC zeroes the subbuffer offset and the subbuffer number parts of
/**************************************/
struct commit_counters {
- local_t cc;
- local_t cc_sb; /* Incremented _once_ at sb switch */
+ long cc; /* ATOMIC */
+ long cc_sb; /* ATOMIC - Incremented _once_ at sb switch */
};
struct ust_buffer {
/* First 32 bytes cache-hot cacheline */
- local_t offset; /* Current offset in the buffer */
+ long offset; /* Current offset in the buffer *atomic* */
struct commit_counters *commit_count; /* Commit count per sub-buffer */
- atomic_long_t consumed; /*
- * Current offset in the buffer
- * standard atomic access (shared)
- */
+ 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 */
- atomic_long_t active_readers; /*
- * Active readers count
- * standard atomic access (shared)
- */
- local_t events_lost;
- local_t corrupted_subbuffers;
+ 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
unsigned int cpu;
/* commit count per subbuffer; must be at end of struct */
- local_t commit_seq[0] ____cacheline_aligned;
+ long commit_seq[0] ____cacheline_aligned; /* ATOMIC */
} ____cacheline_aligned;
/*
long consumed_old, consumed_new;
do {
- consumed_old = atomic_long_read(&buf->consumed);
+ 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
consumed_new = SUBBUF_ALIGN(consumed_old, buf->chan);
else
return;
- } while (unlikely(atomic_long_cmpxchg(&buf->consumed, consumed_old,
+ } while (unlikely(uatomic_cmpxchg(&buf->consumed, consumed_old,
consumed_new) != consumed_old));
}
struct ust_buffer *buf,
long commit_count, long idx)
{
- local_set(&buf->commit_seq[idx], commit_count);
+ uatomic_set(&buf->commit_seq[idx], commit_count);
}
static __inline__ void ltt_check_deliver(struct ust_channel *chan,
* value without adding a add_return atomic operation to the
* fast path.
*/
- if (likely(local_cmpxchg(&buf->commit_count[idx].cc_sb,
+ if (likely(uatomic_cmpxchg(&buf->commit_count[idx].cc_sb,
old_commit_count, commit_count)
== old_commit_count)) {
int result;
{
long consumed_old, consumed_idx, commit_count, write_offset;
- consumed_old = atomic_long_read(&buf->consumed);
+ consumed_old = uatomic_read(&buf->consumed);
consumed_idx = SUBBUF_INDEX(consumed_old, buf->chan);
- commit_count = local_read(&buf->commit_count[consumed_idx].cc_sb);
+ commit_count = uatomic_read(&buf->commit_count[consumed_idx].cc_sb);
/*
* No memory 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 = local_read(&buf->offset);
+ write_offset = uatomic_read(&buf->offset);
/*
* Check that the subbuffer we are trying to consume has been
long *o_begin, long *o_end, long *o_old,
size_t *before_hdr_pad, size_t *size)
{
- *o_begin = local_read(&buf->offset);
+ *o_begin = uatomic_read(&buf->offset);
*o_old = *o_begin;
*tsc = trace_clock_read64();
*/
/* FIXME: make this rellay per cpu? */
if (unlikely(LOAD_SHARED(ltt_nesting) > 4)) {
- local_inc(&buf->events_lost);
+ DBG("Dropping event because nesting is too deep.");
+ uatomic_inc(&buf->events_lost);
return -EPERM;
}
&before_hdr_pad, slot_size)))
goto slow_path;
- if (unlikely(local_cmpxchg(&buf->offset, o_old, o_end) != o_old))
+ if (unlikely(uatomic_cmpxchg(&buf->offset, o_old, o_end) != o_old))
goto slow_path;
/*
* 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.
- *
- * Note, however, that as a local_cmpxchg is used for some atomic
- * operations, this function must be called from the CPU which owns the buffer
- * for a ACTIVE flush.
*/
static __inline__ void ltt_force_switch(struct ust_buffer *buf,
enum force_switch_mode mode)
if (unlikely(SUBBUF_OFFSET(offset - commit_count, buf->chan)))
return;
- commit_seq_old = local_read(&buf->commit_seq[idx]);
+ commit_seq_old = uatomic_read(&buf->commit_seq[idx]);
while (commit_seq_old < commit_count)
- commit_seq_old = local_cmpxchg(&buf->commit_seq[idx],
+ 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);
*/
barrier();
#endif
- local_add(slot_size, &buf->commit_count[endidx].cc);
+ 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
* - 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 local_add ensures this.
+ * 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
* reserve offset for a specific sub-buffer, which is completely
* independent of the order.
*/
- commit_count = local_read(&buf->commit_count[endidx].cc);
+ commit_count = uatomic_read(&buf->commit_count[endidx].cc);
ltt_check_deliver(chan, buf, offset_end - 1, commit_count, endidx);
/*
return len;
}
-int ust_buffers_get_subbuf(struct ust_buffer *buf, long *consumed);
-int ust_buffers_put_subbuf(struct ust_buffer *buf, unsigned long uconsumed_old);
+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 */
projects / ust.git / blobdiff