-#ifndef _LIB_RING_BUFFER_BACKEND_INTERNAL_H
-#define _LIB_RING_BUFFER_BACKEND_INTERNAL_H
-
-/*
+/* SPDX-License-Identifier: (GPL-2.0-only OR LGPL-2.1-only)
+ *
* lib/ringbuffer/backend_internal.h
*
* Ring buffer backend (internal helpers).
*
* Copyright (C) 2008-2012 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
*/
+#ifndef _LIB_RING_BUFFER_BACKEND_INTERNAL_H
+#define _LIB_RING_BUFFER_BACKEND_INTERNAL_H
+
+#include <wrapper/compiler.h>
#include <wrapper/ringbuffer/config.h>
#include <wrapper/ringbuffer/backend_types.h>
#include <wrapper/ringbuffer/frontend_types.h>
tmp |= offset << SB_ID_OFFSET_SHIFT;
tmp |= SB_ID_NOREF_MASK;
/* Volatile store, read concurrently by readers. */
- ACCESS_ONCE(*id) = tmp;
+ WRITE_ONCE(*id, tmp);
}
}
return 0;
}
+static inline
+void lib_ring_buffer_backend_get_pages(const struct lib_ring_buffer_config *config,
+ struct lib_ring_buffer_ctx *ctx,
+ struct lib_ring_buffer_backend_pages **backend_pages)
+{
+ struct lib_ring_buffer_backend *bufb = &ctx->buf->backend;
+ struct channel_backend *chanb = &ctx->chan->backend;
+ size_t sbidx, offset = ctx->buf_offset;
+ unsigned long sb_bindex, id;
+ struct lib_ring_buffer_backend_pages *rpages;
+
+ offset &= chanb->buf_size - 1;
+ sbidx = offset >> chanb->subbuf_size_order;
+ id = bufb->buf_wsb[sbidx].id;
+ sb_bindex = subbuffer_id_get_index(config, id);
+ rpages = bufb->array[sb_bindex];
+ CHAN_WARN_ON(ctx->chan,
+ config->mode == RING_BUFFER_OVERWRITE
+ && subbuffer_id_is_noref(config, id));
+ *backend_pages = rpages;
+}
+
+/* Get backend pages from cache. */
+static inline
+struct lib_ring_buffer_backend_pages *
+ lib_ring_buffer_get_backend_pages_from_ctx(const struct lib_ring_buffer_config *config,
+ struct lib_ring_buffer_ctx *ctx)
+{
+ return ctx->backend_pages;
+}
+
+/*
+ * The ring buffer can count events recorded and overwritten per buffer,
+ * but it is disabled by default due to its performance overhead.
+ */
+#ifdef LTTNG_RING_BUFFER_COUNT_EVENTS
static inline
void subbuffer_count_record(const struct lib_ring_buffer_config *config,
struct lib_ring_buffer_backend *bufb,
sb_bindex = subbuffer_id_get_index(config, bufb->buf_wsb[idx].id);
v_inc(config, &bufb->array[sb_bindex]->records_commit);
}
+#else /* LTTNG_RING_BUFFER_COUNT_EVENTS */
+static inline
+void subbuffer_count_record(const struct lib_ring_buffer_config *config,
+ struct lib_ring_buffer_backend *bufb,
+ unsigned long idx)
+{
+}
+#endif /* #else LTTNG_RING_BUFFER_COUNT_EVENTS */
/*
* Reader has exclusive subbuffer access for record consumption. No need to
* Performing a volatile access to read the sb_pages, because we want to
* read a coherent version of the pointer and the associated noref flag.
*/
- id = ACCESS_ONCE(bufb->buf_wsb[idx].id);
+ id = READ_ONCE(bufb->buf_wsb[idx].id);
for (;;) {
/* This check is called on the fast path for each record. */
if (likely(!subbuffer_id_is_noref(config, id))) {
if (config->mode == RING_BUFFER_OVERWRITE) {
/*
* Exchange the target writer subbuffer with our own unused
- * subbuffer. No need to use ACCESS_ONCE() here to read the
+ * subbuffer. No need to use READ_ONCE() here to read the
* old_wpage, because the value read will be confirmed by the
* following cmpxchg().
*/
return 0;
}
+static inline __attribute__((always_inline))
+void lttng_inline_memcpy(void *dest, const void *src,
+ unsigned long len)
+{
+ switch (len) {
+ case 1:
+ *(uint8_t *) dest = *(const uint8_t *) src;
+ break;
+ case 2:
+ *(uint16_t *) dest = *(const uint16_t *) src;
+ break;
+ case 4:
+ *(uint32_t *) dest = *(const uint32_t *) src;
+ break;
+ case 8:
+ *(uint64_t *) dest = *(const uint64_t *) src;
+ break;
+ default:
+ inline_memcpy(dest, src, len);
+ }
+}
+
/*
* Use the architecture-specific memcpy implementation for constant-sized
* inputs, but rely on an inline memcpy for length statically unknown.
if (__builtin_constant_p(len)) \
memcpy(dest, src, __len); \
else \
- inline_memcpy(dest, src, __len); \
+ lttng_inline_memcpy(dest, src, __len); \
} while (0)
/*
* We use __copy_from_user_inatomic to copy userspace data since we already
* did the access_ok for the whole range.
+ *
+ * Return 0 if OK, nonzero on error.
*/
static inline
unsigned long lib_ring_buffer_do_copy_from_user_inatomic(void *dest,
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