-#ifndef _LINUX_RING_BUFFER_FRONTEND_INTERNAL_H
-#define _LINUX_RING_BUFFER_FRONTEND_INTERNAL_H
+#ifndef _LTTNG_RING_BUFFER_FRONTEND_INTERNAL_H
+#define _LTTNG_RING_BUFFER_FRONTEND_INTERNAL_H
/*
- * linux/ringbuffer/frontend_internal.h
- *
- * (C) Copyright 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * libringbuffer/frontend_internal.h
*
* Ring Buffer Library Synchronization Header (internal helpers).
*
+ * 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
+ *
+ *
* Author:
* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
*/
#include <urcu/compiler.h>
+#include <signal.h>
+#include <pthread.h>
-#include "config.h"
+#include <lttng/ringbuffer-config.h>
#include "backend_types.h"
#include "frontend_types.h"
+#include "shm.h"
/* Buffer offset macros */
#if (CAA_BITS_PER_LONG == 32)
static inline
-void save_last_tsc(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf, u64 tsc)
+void save_last_tsc(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc)
{
if (config->tsc_bits == 0 || config->tsc_bits == 64)
return;
}
static inline
-int last_tsc_overflow(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf, u64 tsc)
+int last_tsc_overflow(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc)
{
unsigned long tsc_shifted;
return 0;
tsc_shifted = (unsigned long)(tsc >> config->tsc_bits);
- if (unlikely(tsc_shifted
+ if (caa_unlikely(tsc_shifted
- (unsigned long)v_read(config, &buf->last_tsc)))
return 1;
else
}
#else
static inline
-void save_last_tsc(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf, u64 tsc)
+void save_last_tsc(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc)
{
if (config->tsc_bits == 0 || config->tsc_bits == 64)
return;
}
static inline
-int last_tsc_overflow(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf, u64 tsc)
+int last_tsc_overflow(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc)
{
if (config->tsc_bits == 0 || config->tsc_bits == 64)
return 0;
- if (unlikely((tsc - v_read(config, &buf->last_tsc))
+ if (caa_unlikely((tsc - v_read(config, &buf->last_tsc))
>> config->tsc_bits))
return 1;
else
#endif
extern
-int lib_ring_buffer_reserve_slow(struct lib_ring_buffer_ctx *ctx);
+int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx);
extern
-void lib_ring_buffer_switch_slow(struct lib_ring_buffer *buf,
- enum switch_mode mode);
+void lib_ring_buffer_switch_slow(struct lttng_ust_lib_ring_buffer *buf,
+ enum switch_mode mode,
+ struct lttng_ust_shm_handle *handle);
/* Buffer write helpers */
static inline
-void lib_ring_buffer_reserve_push_reader(struct lib_ring_buffer *buf,
+void lib_ring_buffer_reserve_push_reader(struct lttng_ust_lib_ring_buffer *buf,
struct channel *chan,
unsigned long offset)
{
* write position sub-buffer index in the buffer being the one
* which will win this loop.
*/
- if (unlikely(subbuf_trunc(offset, chan)
+ if (caa_unlikely(subbuf_trunc(offset, chan)
- subbuf_trunc(consumed_old, chan)
>= chan->backend.buf_size))
consumed_new = subbuf_align(consumed_old, chan);
else
return;
- } while (unlikely(uatomic_cmpxchg(&buf->consumed, consumed_old,
+ } while (caa_unlikely(uatomic_cmpxchg(&buf->consumed, consumed_old,
consumed_new) != consumed_old));
}
static inline
-void lib_ring_buffer_vmcore_check_deliver(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf,
+void lib_ring_buffer_vmcore_check_deliver(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf,
unsigned long commit_count,
- unsigned long idx)
+ unsigned long idx,
+ struct lttng_ust_shm_handle *handle)
{
if (config->oops == RING_BUFFER_OOPS_CONSISTENCY)
- v_set(config, &buf->commit_hot[idx].seq, commit_count);
+ v_set(config, &shmp_index(handle, buf->commit_hot, idx)->seq, commit_count);
}
static inline
-int lib_ring_buffer_poll_deliver(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf,
- struct channel *chan)
+int lib_ring_buffer_poll_deliver(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf,
+ struct channel *chan,
+ struct lttng_ust_shm_handle *handle)
{
unsigned long consumed_old, consumed_idx, commit_count, write_offset;
consumed_old = uatomic_read(&buf->consumed);
consumed_idx = subbuf_index(consumed_old, chan);
- commit_count = v_read(config, &buf->commit_cold[consumed_idx].cc_sb);
+ commit_count = v_read(config, &shmp_index(handle, buf->commit_cold, consumed_idx)->cc_sb);
/*
* No memory barrier here, since we are only interested
* in a statistically correct polling result. The next poll will
}
static inline
-int lib_ring_buffer_pending_data(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf,
+int lib_ring_buffer_pending_data(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf,
struct channel *chan)
{
return !!subbuf_offset(v_read(config, &buf->offset), chan);
}
static inline
-unsigned long lib_ring_buffer_get_data_size(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf,
- unsigned long idx)
+unsigned long lib_ring_buffer_get_data_size(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf,
+ unsigned long idx,
+ struct lttng_ust_shm_handle *handle)
{
- return subbuffer_get_data_size(config, &buf->backend, idx);
+ return subbuffer_get_data_size(config, &buf->backend, idx, handle);
}
/*
* This is a very specific ftrace use-case, so we keep this as "internal" API.
*/
static inline
-int lib_ring_buffer_reserve_committed(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf,
- struct channel *chan)
+int lib_ring_buffer_reserve_committed(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf,
+ struct channel *chan,
+ struct lttng_ust_shm_handle *handle)
{
unsigned long offset, idx, commit_count;
do {
offset = v_read(config, &buf->offset);
idx = subbuf_index(offset, chan);
- commit_count = v_read(config, &buf->commit_hot[idx].cc);
+ commit_count = v_read(config, &shmp_index(handle, buf->commit_hot, idx)->cc);
} while (offset != v_read(config, &buf->offset));
return ((buf_trunc(offset, chan) >> chan->backend.num_subbuf_order)
}
static inline
-void lib_ring_buffer_check_deliver(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf,
+void lib_ring_buffer_check_deliver(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf,
struct channel *chan,
unsigned long offset,
unsigned long commit_count,
- unsigned long idx)
+ unsigned long idx,
+ struct lttng_ust_shm_handle *handle)
{
unsigned long old_commit_count = commit_count
- chan->backend.subbuf_size;
- u64 tsc;
+ uint64_t tsc;
/* Check if all commits have been done */
- if (unlikely((buf_trunc(offset, chan) >> chan->backend.num_subbuf_order)
+ if (caa_unlikely((buf_trunc(offset, chan) >> chan->backend.num_subbuf_order)
- (old_commit_count & chan->commit_count_mask) == 0)) {
/*
* If we succeeded at updating cc_sb below, we are the subbuffer
* The subbuffer size is least 2 bytes (minimum size: 1 page).
* This guarantees that old_commit_count + 1 != commit_count.
*/
- if (likely(v_cmpxchg(config, &buf->commit_cold[idx].cc_sb,
+ if (caa_likely(v_cmpxchg(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
old_commit_count, old_commit_count + 1)
== old_commit_count)) {
/*
tsc = config->cb.ring_buffer_clock_read(chan);
v_add(config,
subbuffer_get_records_count(config,
- &buf->backend, idx),
+ &buf->backend,
+ idx, handle),
&buf->records_count);
v_add(config,
subbuffer_count_records_overrun(config,
&buf->backend,
- idx),
+ idx, handle),
&buf->records_overrun);
config->cb.buffer_end(buf, tsc, idx,
lib_ring_buffer_get_data_size(config,
buf,
- idx));
+ idx,
+ handle),
+ handle);
/*
* Set noref flag and offset for this subbuffer id.
* are ordered before set noref and offset.
*/
lib_ring_buffer_set_noref_offset(config, &buf->backend, idx,
- buf_trunc_val(offset, chan));
+ buf_trunc_val(offset, chan), handle);
/*
* Order set_noref and record counter updates before the
*/
cmm_smp_mb();
/* End of exclusive subbuffer access */
- v_set(config, &buf->commit_cold[idx].cc_sb,
+ v_set(config, &shmp_index(handle, buf->commit_cold, idx)->cc_sb,
commit_count);
lib_ring_buffer_vmcore_check_deliver(config, buf,
- commit_count, idx);
+ commit_count, idx, handle);
/*
* RING_BUFFER_WAKEUP_BY_WRITER wakeup is not lock-free.
*/
if (config->wakeup == RING_BUFFER_WAKEUP_BY_WRITER
- && uatomic_read(&buf->active_readers)
- && lib_ring_buffer_poll_deliver(config, buf, chan)) {
- //wake_up_interruptible(&buf->read_wait);
- //wake_up_interruptible(&chan->read_wait);
+ && (uatomic_read(&buf->active_readers)
+ || uatomic_read(&buf->active_shadow_readers))
+ && lib_ring_buffer_poll_deliver(config, buf, chan, handle)) {
+ int wakeup_fd = shm_get_wakeup_fd(handle, &buf->self._ref);
+
+ if (wakeup_fd >= 0) {
+ sigset_t sigpipe_set, pending_set, old_set;
+ int ret, sigpipe_was_pending = 0;
+
+ /*
+ * Wake-up the other end by
+ * writing a null byte in the
+ * pipe (non-blocking).
+ * Important note: Because
+ * writing into the pipe is
+ * non-blocking (and therefore
+ * we allow dropping wakeup
+ * data, as long as there is
+ * wakeup data present in the
+ * pipe buffer to wake up the
+ * consumer), the consumer
+ * should perform the following
+ * sequence for waiting:
+ * 1) empty the pipe (reads).
+ * 2) check if there is data in
+ * the buffer.
+ * 3) wait on the pipe (poll).
+ *
+ * Discard the SIGPIPE from write(), not
+ * disturbing any SIGPIPE that might be
+ * already pending. If a bogus SIGPIPE
+ * is sent to the entire process
+ * concurrently by a malicious user, it
+ * may be simply discarded.
+ */
+ ret = sigemptyset(&pending_set);
+ assert(!ret);
+ /*
+ * sigpending returns the mask
+ * of signals that are _both_
+ * blocked for the thread _and_
+ * pending for either the thread
+ * or the entire process.
+ */
+ ret = sigpending(&pending_set);
+ assert(!ret);
+ sigpipe_was_pending = sigismember(&pending_set, SIGPIPE);
+ /*
+ * If sigpipe was pending, it
+ * means it was already blocked,
+ * so no need to block it.
+ */
+ if (!sigpipe_was_pending) {
+ ret = sigemptyset(&sigpipe_set);
+ assert(!ret);
+ ret = sigaddset(&sigpipe_set, SIGPIPE);
+ assert(!ret);
+ ret = pthread_sigmask(SIG_BLOCK, &sigpipe_set, &old_set);
+ assert(!ret);
+ }
+ do {
+ ret = write(wakeup_fd, "", 1);
+ } while (ret == -1L && errno == EINTR);
+ if (ret == -1L && errno == EPIPE && !sigpipe_was_pending) {
+ struct timespec timeout = { 0, 0 };
+ do {
+ ret = sigtimedwait(&sigpipe_set, NULL,
+ &timeout);
+ } while (ret == -1L && errno == EINTR);
+ }
+ if (!sigpipe_was_pending) {
+ ret = pthread_sigmask(SIG_SETMASK, &old_set, NULL);
+ assert(!ret);
+ }
+ }
}
-
}
}
}
* useful for crash dump.
*/
static inline
-void lib_ring_buffer_write_commit_counter(const struct lib_ring_buffer_config *config,
- struct lib_ring_buffer *buf,
+void lib_ring_buffer_write_commit_counter(const struct lttng_ust_lib_ring_buffer_config *config,
+ struct lttng_ust_lib_ring_buffer *buf,
struct channel *chan,
unsigned long idx,
unsigned long buf_offset,
unsigned long commit_count,
- size_t slot_size)
+ size_t slot_size,
+ struct lttng_ust_shm_handle *handle)
{
unsigned long offset, commit_seq_old;
* buffer full/empty mismatch because offset is never zero here
* (subbuffer header and record headers have non-zero length).
*/
- if (unlikely(subbuf_offset(offset - commit_count, chan)))
+ if (caa_unlikely(subbuf_offset(offset - commit_count, chan)))
return;
- commit_seq_old = v_read(config, &buf->commit_hot[idx].seq);
+ commit_seq_old = v_read(config, &shmp_index(handle, buf->commit_hot, idx)->seq);
while ((long) (commit_seq_old - commit_count) < 0)
- commit_seq_old = v_cmpxchg(config, &buf->commit_hot[idx].seq,
+ commit_seq_old = v_cmpxchg(config, &shmp_index(handle, buf->commit_hot, idx)->seq,
commit_seq_old, commit_count);
}
-extern int lib_ring_buffer_create(struct lib_ring_buffer *buf,
- struct channel_backend *chanb, int cpu);
-extern void lib_ring_buffer_free(struct lib_ring_buffer *buf);
+extern int lib_ring_buffer_create(struct lttng_ust_lib_ring_buffer *buf,
+ struct channel_backend *chanb, int cpu,
+ struct lttng_ust_shm_handle *handle,
+ struct shm_object *shmobj);
+extern void lib_ring_buffer_free(struct lttng_ust_lib_ring_buffer *buf,
+ struct lttng_ust_shm_handle *handle);
/* Keep track of trap nesting inside ring buffer code */
extern __thread unsigned int lib_ring_buffer_nesting;
-#endif /* _LINUX_RING_BUFFER_FRONTEND_INTERNAL_H */
+#endif /* _LTTNG_RING_BUFFER_FRONTEND_INTERNAL_H */
projects / lttng-ust.git / blobdiff