-#ifndef _LINUX_RING_BUFFER_FRONTEND_API_H
-#define _LINUX_RING_BUFFER_FRONTEND_API_H
-
/*
- * linux/ringbuffer/frontend_api.h
- *
- * (C) Copyright 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Ring Buffer Library Synchronization Header (buffer write API).
+ * SPDX-License-Identifier: LGPL-2.1-only
*
- * Author:
- * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2005-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * See ring_buffer_frontend.c for more information on wait-free algorithms.
- * See linux/ringbuffer/frontend.h for channel allocation and read-side API.
- *
- * Dual LGPL v2.1/GPL v2 license.
+ * See ring_buffer_frontend.c for more information on wait-free
+ * algorithms.
+ * See frontend.h for channel allocation and read-side API.
*/
-#include "frontend.h"
-#include "lttng/core.h"
-#include <urcu-bp.h>
+#ifndef _LTTNG_RING_BUFFER_FRONTEND_API_H
+#define _LTTNG_RING_BUFFER_FRONTEND_API_H
+
+#include <stddef.h>
+
#include <urcu/compiler.h>
+#include "frontend.h"
+
/**
* lib_ring_buffer_get_cpu - Precedes ring buffer reserve/commit.
*
- * Grabs RCU read-side lock and keeps a ring buffer nesting count as
- * supplementary safety net to ensure tracer client code will never
- * trigger an endless recursion. Returns the processor ID on success,
- * -EPERM on failure (nesting count too high).
+ * Keeps a ring buffer nesting count as supplementary safety net to
+ * ensure tracer client code will never trigger an endless recursion.
+ * Returns the processor ID on success, -EPERM on failure (nesting count
+ * too high).
*
* asm volatile and "memory" clobber prevent the compiler from moving
* instructions out of the ring buffer nesting count. This is required to ensure
{
int cpu, nesting;
- rcu_read_lock();
- cpu = ust_get_cpu();
- nesting = ++lib_ring_buffer_nesting; /* TLS */
+ cpu = lttng_ust_get_cpu();
+ nesting = ++URCU_TLS(lib_ring_buffer_nesting);
cmm_barrier();
if (caa_unlikely(nesting > 4)) {
WARN_ON_ONCE(1);
- lib_ring_buffer_nesting--; /* TLS */
- rcu_read_unlock();
+ URCU_TLS(lib_ring_buffer_nesting)--;
return -EPERM;
} else
return cpu;
void lib_ring_buffer_put_cpu(const struct lttng_ust_lib_ring_buffer_config *config)
{
cmm_barrier();
- lib_ring_buffer_nesting--; /* TLS */
- rcu_read_unlock();
+ URCU_TLS(lib_ring_buffer_nesting)--; /* TLS */
}
/*
static inline
int lib_ring_buffer_try_reserve(const struct lttng_ust_lib_ring_buffer_config *config,
struct lttng_ust_lib_ring_buffer_ctx *ctx,
+ void *client_ctx,
unsigned long *o_begin, unsigned long *o_end,
unsigned long *o_old, size_t *before_hdr_pad)
{
return 1;
ctx->slot_size = record_header_size(config, chan, *o_begin,
- before_hdr_pad, ctx);
+ before_hdr_pad, ctx, client_ctx);
ctx->slot_size +=
lib_ring_buffer_align(*o_begin + ctx->slot_size,
ctx->largest_align) + ctx->data_size;
static inline
int lib_ring_buffer_reserve(const struct lttng_ust_lib_ring_buffer_config *config,
- struct lttng_ust_lib_ring_buffer_ctx *ctx)
+ struct lttng_ust_lib_ring_buffer_ctx *ctx,
+ void *client_ctx)
{
struct channel *chan = ctx->chan;
struct lttng_ust_shm_handle *handle = ctx->handle;
unsigned long o_begin, o_end, o_old;
size_t before_hdr_pad = 0;
- if (uatomic_read(&chan->record_disabled))
+ if (caa_unlikely(uatomic_read(&chan->record_disabled)))
return -EAGAIN;
if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
buf = shmp(handle, chan->backend.buf[ctx->cpu].shmp);
else
buf = shmp(handle, chan->backend.buf[0].shmp);
- if (uatomic_read(&buf->record_disabled))
+ if (caa_unlikely(!buf))
+ return -EIO;
+ if (caa_unlikely(uatomic_read(&buf->record_disabled)))
return -EAGAIN;
ctx->buf = buf;
/*
* Perform retryable operations.
*/
- if (caa_unlikely(lib_ring_buffer_try_reserve(config, ctx, &o_begin,
+ if (caa_unlikely(lib_ring_buffer_try_reserve(config, ctx, client_ctx, &o_begin,
&o_end, &o_old, &before_hdr_pad)))
goto slow_path;
ctx->buf_offset = o_begin + before_hdr_pad;
return 0;
slow_path:
- return lib_ring_buffer_reserve_slow(ctx);
+ return lib_ring_buffer_reserve_slow(ctx, client_ctx);
}
/**
unsigned long offset_end = ctx->buf_offset;
unsigned long endidx = subbuf_index(offset_end - 1, chan);
unsigned long commit_count;
+ struct commit_counters_hot *cc_hot = shmp_index(handle,
+ buf->commit_hot, endidx);
+
+ if (caa_unlikely(!cc_hot))
+ return;
/*
* Must count record before incrementing the commit count.
*/
- subbuffer_count_record(config, &buf->backend, endidx, handle);
+ subbuffer_count_record(config, ctx, &buf->backend, endidx, handle);
/*
* Order all writes to buffer before the commit count update that will
*/
cmm_smp_wmb();
- v_add(config, ctx->slot_size, &shmp_index(handle, buf->commit_hot, endidx)->cc);
+ v_add(config, ctx->slot_size, &cc_hot->cc);
/*
* commit count read can race with concurrent OOO commit count updates.
* count reaches back the reserve offset for a specific sub-buffer,
* which is completely independent of the order.
*/
- commit_count = v_read(config, &shmp_index(handle, buf->commit_hot, endidx)->cc);
+ commit_count = v_read(config, &cc_hot->cc);
lib_ring_buffer_check_deliver(config, buf, chan, offset_end - 1,
- commit_count, endidx, handle);
+ commit_count, endidx, handle, ctx->tsc);
/*
* Update used size at each commit. It's needed only for extracting
* ring_buffer buffers from vmcore, after crash.
*/
- lib_ring_buffer_write_commit_counter(config, buf, chan, endidx,
- ctx->buf_offset, commit_count,
- ctx->slot_size, handle);
+ lib_ring_buffer_write_commit_counter(config, buf, chan,
+ offset_end, commit_count, handle, cc_hot);
}
/**
uatomic_dec(&buf->record_disabled);
}
-#endif /* _LINUX_RING_BUFFER_FRONTEND_API_H */
+#endif /* _LTTNG_RING_BUFFER_FRONTEND_API_H */
projects / lttng-ust.git / blobdiff