Implement file-backed ring buffer
[lttng-ust.git] / libringbuffer / backend_internal.h
index 061924fcfa5091d32a76a8949c37d7fae49db03c..3c09382ed117b262f5f4baf275043271f069359d 100644 (file)
@@ -1,20 +1,32 @@
-#ifndef _LINUX_RING_BUFFER_BACKEND_INTERNAL_H
-#define _LINUX_RING_BUFFER_BACKEND_INTERNAL_H
+#ifndef _LTTNG_RING_BUFFER_BACKEND_INTERNAL_H
+#define _LTTNG_RING_BUFFER_BACKEND_INTERNAL_H
 
 /*
- * linux/ringbuffer/backend_internal.h
- *
- * Copyright (C) 2008-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * libringbuffer/backend_internal.h
  *
  * Ring buffer backend (internal helpers).
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * 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
  */
 
 #include <unistd.h>
 #include <urcu/compiler.h>
 
-#include <ust/ringbuffer-config.h>
+#include <lttng/ringbuffer-config.h>
 #include "backend_types.h"
 #include "frontend_types.h"
 #include "shm.h"
 
 /* Ring buffer and channel backend create/free */
 
-int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb,
+int lib_ring_buffer_backend_create(struct lttng_ust_lib_ring_buffer_backend *bufb,
                                   struct channel_backend *chan, int cpu,
-                                  struct shm_header *shm_header);
+                                  struct lttng_ust_shm_handle *handle,
+                                  struct shm_object *shmobj);
 void channel_backend_unregister_notifiers(struct channel_backend *chanb);
-void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb);
+void lib_ring_buffer_backend_free(struct lttng_ust_lib_ring_buffer_backend *bufb);
 int channel_backend_init(struct channel_backend *chanb,
                         const char *name,
-                        const struct lib_ring_buffer_config *config,
-                        void *priv, size_t subbuf_size,
-                        size_t num_subbuf, struct shm_header *shm_header);
-void channel_backend_free(struct channel_backend *chanb);
-
-void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb);
+                        const struct lttng_ust_lib_ring_buffer_config *config,
+                        size_t subbuf_size,
+                        size_t num_subbuf, struct lttng_ust_shm_handle *handle,
+                        const char *shm_path);
+void channel_backend_free(struct channel_backend *chanb,
+                         struct lttng_ust_shm_handle *handle);
+
+void lib_ring_buffer_backend_reset(struct lttng_ust_lib_ring_buffer_backend *bufb,
+                                  struct lttng_ust_shm_handle *handle);
 void channel_backend_reset(struct channel_backend *chanb);
 
 int lib_ring_buffer_backend_init(void);
 void lib_ring_buffer_backend_exit(void);
 
-extern void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb,
+extern void _lib_ring_buffer_write(struct lttng_ust_lib_ring_buffer_backend *bufb,
                                   size_t offset, const void *src, size_t len,
                                   ssize_t pagecpy);
 
@@ -83,7 +99,7 @@ extern void _lib_ring_buffer_write(struct lib_ring_buffer_backend *bufb,
  * mode).
  */
 static inline
-unsigned long subbuffer_id(const struct lib_ring_buffer_config *config,
+unsigned long subbuffer_id(const struct lttng_ust_lib_ring_buffer_config *config,
                           unsigned long offset, unsigned long noref,
                           unsigned long index)
 {
@@ -100,14 +116,14 @@ unsigned long subbuffer_id(const struct lib_ring_buffer_config *config,
  * bits are identical, else 0.
  */
 static inline
-int subbuffer_id_compare_offset(const struct lib_ring_buffer_config *config,
+int subbuffer_id_compare_offset(const struct lttng_ust_lib_ring_buffer_config *config,
                                unsigned long id, unsigned long offset)
 {
        return (id & SB_ID_OFFSET_MASK) == (offset << SB_ID_OFFSET_SHIFT);
 }
 
 static inline
-unsigned long subbuffer_id_get_index(const struct lib_ring_buffer_config *config,
+unsigned long subbuffer_id_get_index(const struct lttng_ust_lib_ring_buffer_config *config,
                                     unsigned long id)
 {
        if (config->mode == RING_BUFFER_OVERWRITE)
@@ -117,7 +133,7 @@ unsigned long subbuffer_id_get_index(const struct lib_ring_buffer_config *config
 }
 
 static inline
-unsigned long subbuffer_id_is_noref(const struct lib_ring_buffer_config *config,
+unsigned long subbuffer_id_is_noref(const struct lttng_ust_lib_ring_buffer_config *config,
                                    unsigned long id)
 {
        if (config->mode == RING_BUFFER_OVERWRITE)
@@ -131,7 +147,7 @@ unsigned long subbuffer_id_is_noref(const struct lib_ring_buffer_config *config,
  * needed.
  */
 static inline
-void subbuffer_id_set_noref(const struct lib_ring_buffer_config *config,
+void subbuffer_id_set_noref(const struct lttng_ust_lib_ring_buffer_config *config,
                            unsigned long *id)
 {
        if (config->mode == RING_BUFFER_OVERWRITE)
@@ -139,7 +155,7 @@ void subbuffer_id_set_noref(const struct lib_ring_buffer_config *config,
 }
 
 static inline
-void subbuffer_id_set_noref_offset(const struct lib_ring_buffer_config *config,
+void subbuffer_id_set_noref_offset(const struct lttng_ust_lib_ring_buffer_config *config,
                                   unsigned long *id, unsigned long offset)
 {
        unsigned long tmp;
@@ -156,7 +172,7 @@ void subbuffer_id_set_noref_offset(const struct lib_ring_buffer_config *config,
 
 /* No volatile access, since already used locally */
 static inline
-void subbuffer_id_clear_noref(const struct lib_ring_buffer_config *config,
+void subbuffer_id_clear_noref(const struct lttng_ust_lib_ring_buffer_config *config,
                              unsigned long *id)
 {
        if (config->mode == RING_BUFFER_OVERWRITE)
@@ -171,7 +187,7 @@ void subbuffer_id_clear_noref(const struct lib_ring_buffer_config *config,
  * -EPERM on failure.
  */
 static inline
-int subbuffer_id_check_index(const struct lib_ring_buffer_config *config,
+int subbuffer_id_check_index(const struct lttng_ust_lib_ring_buffer_config *config,
                             unsigned long num_subbuf)
 {
        if (config->mode == RING_BUFFER_OVERWRITE)
@@ -181,14 +197,14 @@ int subbuffer_id_check_index(const struct lib_ring_buffer_config *config,
 }
 
 static inline
-void subbuffer_count_record(const struct lib_ring_buffer_config *config,
-                           struct lib_ring_buffer_backend *bufb,
-                           unsigned long idx)
+void subbuffer_count_record(const struct lttng_ust_lib_ring_buffer_config *config,
+                           struct lttng_ust_lib_ring_buffer_backend *bufb,
+                           unsigned long idx, struct lttng_ust_shm_handle *handle)
 {
        unsigned long sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
-       v_inc(config, &shmp(bufb->array)[sb_bindex]->records_commit);
+       sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id);
+       v_inc(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_commit);
 }
 
 /*
@@ -196,95 +212,102 @@ void subbuffer_count_record(const struct lib_ring_buffer_config *config,
  * perform the decrement atomically.
  */
 static inline
-void subbuffer_consume_record(const struct lib_ring_buffer_config *config,
-                             struct lib_ring_buffer_backend *bufb)
+void subbuffer_consume_record(const struct lttng_ust_lib_ring_buffer_config *config,
+                             struct lttng_ust_lib_ring_buffer_backend *bufb,
+                             struct lttng_ust_shm_handle *handle)
 {
        unsigned long sb_bindex;
 
        sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id);
-       CHAN_WARN_ON(bufb->chan,
-                    !v_read(config, &shmp(bufb->array)[sb_bindex]->records_unread));
+       CHAN_WARN_ON(shmp(handle, bufb->chan),
+                    !v_read(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_unread));
        /* Non-atomic decrement protected by exclusive subbuffer access */
-       _v_dec(config, &shmp(bufb->array)[sb_bindex]->records_unread);
+       _v_dec(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_unread);
        v_inc(config, &bufb->records_read);
 }
 
 static inline
 unsigned long subbuffer_get_records_count(
-                               const struct lib_ring_buffer_config *config,
-                               struct lib_ring_buffer_backend *bufb,
-                               unsigned long idx)
+                               const struct lttng_ust_lib_ring_buffer_config *config,
+                               struct lttng_ust_lib_ring_buffer_backend *bufb,
+                               unsigned long idx,
+                               struct lttng_ust_shm_handle *handle)
 {
        unsigned long sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
-       return v_read(config, &shmp(bufb->array)[sb_bindex]->records_commit);
+       sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id);
+       return v_read(config, &shmp(handle, shmp_index(handle, bufb->array, sb_bindex)->shmp)->records_commit);
 }
 
 /*
  * Must be executed at subbuffer delivery when the writer has _exclusive_
- * subbuffer access. See ring_buffer_check_deliver() for details.
- * ring_buffer_get_records_count() must be called to get the records count
- * before this function, because it resets the records_commit count.
+ * subbuffer access. See lib_ring_buffer_check_deliver() for details.
+ * lib_ring_buffer_get_records_count() must be called to get the records
+ * count before this function, because it resets the records_commit
+ * count.
  */
 static inline
 unsigned long subbuffer_count_records_overrun(
-                               const struct lib_ring_buffer_config *config,
-                               struct lib_ring_buffer_backend *bufb,
-                               unsigned long idx)
+                               const struct lttng_ust_lib_ring_buffer_config *config,
+                               struct lttng_ust_lib_ring_buffer_backend *bufb,
+                               unsigned long idx,
+                               struct lttng_ust_shm_handle *handle)
 {
-       struct lib_ring_buffer_backend_pages *pages;
+       struct lttng_ust_lib_ring_buffer_backend_pages_shmp *pages;
        unsigned long overruns, sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
-       pages = shmp(bufb->array)[sb_bindex];
-       overruns = v_read(config, &pages->records_unread);
-       v_set(config, &pages->records_unread,
-             v_read(config, &pages->records_commit));
-       v_set(config, &pages->records_commit, 0);
+       sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id);
+       pages = shmp_index(handle, bufb->array, sb_bindex);
+       overruns = v_read(config, &shmp(handle, pages->shmp)->records_unread);
+       v_set(config, &shmp(handle, pages->shmp)->records_unread,
+             v_read(config, &shmp(handle, pages->shmp)->records_commit));
+       v_set(config, &shmp(handle, pages->shmp)->records_commit, 0);
 
        return overruns;
 }
 
 static inline
-void subbuffer_set_data_size(const struct lib_ring_buffer_config *config,
-                            struct lib_ring_buffer_backend *bufb,
+void subbuffer_set_data_size(const struct lttng_ust_lib_ring_buffer_config *config,
+                            struct lttng_ust_lib_ring_buffer_backend *bufb,
                             unsigned long idx,
-                            unsigned long data_size)
+                            unsigned long data_size,
+                            struct lttng_ust_shm_handle *handle)
 {
-       struct lib_ring_buffer_backend_pages *pages;
+       struct lttng_ust_lib_ring_buffer_backend_pages_shmp *pages;
        unsigned long sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
-       pages = shmp(bufb->array)[sb_bindex];
-       pages->data_size = data_size;
+       sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id);
+       pages = shmp_index(handle, bufb->array, sb_bindex);
+       shmp(handle, pages->shmp)->data_size = data_size;
 }
 
 static inline
 unsigned long subbuffer_get_read_data_size(
-                               const struct lib_ring_buffer_config *config,
-                               struct lib_ring_buffer_backend *bufb)
+                               const struct lttng_ust_lib_ring_buffer_config *config,
+                               struct lttng_ust_lib_ring_buffer_backend *bufb,
+                               struct lttng_ust_shm_handle *handle)
 {
-       struct lib_ring_buffer_backend_pages *pages;
+       struct lttng_ust_lib_ring_buffer_backend_pages_shmp *pages;
        unsigned long sb_bindex;
 
        sb_bindex = subbuffer_id_get_index(config, bufb->buf_rsb.id);
-       pages = shmp(bufb->array)[sb_bindex];
-       return pages->data_size;
+       pages = shmp_index(handle, bufb->array, sb_bindex);
+       return shmp(handle, pages->shmp)->data_size;
 }
 
 static inline
 unsigned long subbuffer_get_data_size(
-                               const struct lib_ring_buffer_config *config,
-                               struct lib_ring_buffer_backend *bufb,
-                               unsigned long idx)
+                               const struct lttng_ust_lib_ring_buffer_config *config,
+                               struct lttng_ust_lib_ring_buffer_backend *bufb,
+                               unsigned long idx,
+                               struct lttng_ust_shm_handle *handle)
 {
-       struct lib_ring_buffer_backend_pages *pages;
+       struct lttng_ust_lib_ring_buffer_backend_pages_shmp *pages;
        unsigned long sb_bindex;
 
-       sb_bindex = subbuffer_id_get_index(config, shmp(bufb->buf_wsb)[idx].id);
-       pages = shmp(bufb->array)[sb_bindex];
-       return pages->data_size;
+       sb_bindex = subbuffer_id_get_index(config, shmp_index(handle, bufb->buf_wsb, idx)->id);
+       pages = shmp_index(handle, bufb->array, sb_bindex);
+       return shmp(handle, pages->shmp)->data_size;
 }
 
 /**
@@ -292,9 +315,10 @@ unsigned long subbuffer_get_data_size(
  *                               writer.
  */
 static inline
-void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config,
-                                struct lib_ring_buffer_backend *bufb,
-                                unsigned long idx)
+void lib_ring_buffer_clear_noref(const struct lttng_ust_lib_ring_buffer_config *config,
+                                struct lttng_ust_lib_ring_buffer_backend *bufb,
+                                unsigned long idx,
+                                struct lttng_ust_shm_handle *handle)
 {
        unsigned long id, new_id;
 
@@ -305,10 +329,10 @@ void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config,
         * 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 = CMM_ACCESS_ONCE(shmp(bufb->buf_wsb)[idx].id);
+       id = CMM_ACCESS_ONCE(shmp_index(handle, 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 (caa_likely(!subbuffer_id_is_noref(config, id))) {
                        /*
                         * Store after load dependency ordering the writes to
                         * the subbuffer after load and test of the noref flag
@@ -319,8 +343,8 @@ void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config,
                }
                new_id = id;
                subbuffer_id_clear_noref(config, &new_id);
-               new_id = uatomic_cmpxchg(&shmp(bufb->buf_wsb)[idx].id, id, new_id);
-               if (likely(new_id == id))
+               new_id = uatomic_cmpxchg(&shmp_index(handle, bufb->buf_wsb, idx)->id, id, new_id);
+               if (caa_likely(new_id == id))
                        break;
                id = new_id;
        }
@@ -331,9 +355,10 @@ void lib_ring_buffer_clear_noref(const struct lib_ring_buffer_config *config,
  *                                    called by writer.
  */
 static inline
-void lib_ring_buffer_set_noref_offset(const struct lib_ring_buffer_config *config,
-                                     struct lib_ring_buffer_backend *bufb,
-                                     unsigned long idx, unsigned long offset)
+void lib_ring_buffer_set_noref_offset(const struct lttng_ust_lib_ring_buffer_config *config,
+                                     struct lttng_ust_lib_ring_buffer_backend *bufb,
+                                     unsigned long idx, unsigned long offset,
+                                     struct lttng_ust_shm_handle *handle)
 {
        if (config->mode != RING_BUFFER_OVERWRITE)
                return;
@@ -349,25 +374,26 @@ void lib_ring_buffer_set_noref_offset(const struct lib_ring_buffer_config *confi
         * subbuffer_set_noref() uses a volatile store to deal with concurrent
         * readers of the noref flag.
         */
-       CHAN_WARN_ON(bufb->chan,
-                    subbuffer_id_is_noref(config, shmp(bufb->buf_wsb)[idx].id));
+       CHAN_WARN_ON(shmp(handle, bufb->chan),
+                    subbuffer_id_is_noref(config, shmp_index(handle, bufb->buf_wsb, idx)->id));
        /*
         * Memory barrier that ensures counter stores are ordered before set
         * noref and offset.
         */
        cmm_smp_mb();
-       subbuffer_id_set_noref_offset(config, &shmp(bufb->buf_wsb)[idx].id, offset);
+       subbuffer_id_set_noref_offset(config, &shmp_index(handle, bufb->buf_wsb, idx)->id, offset);
 }
 
 /**
  * update_read_sb_index - Read-side subbuffer index update.
  */
 static inline
-int update_read_sb_index(const struct lib_ring_buffer_config *config,
-                        struct lib_ring_buffer_backend *bufb,
+int update_read_sb_index(const struct lttng_ust_lib_ring_buffer_config *config,
+                        struct lttng_ust_lib_ring_buffer_backend *bufb,
                         struct channel_backend *chanb,
                         unsigned long consumed_idx,
-                        unsigned long consumed_count)
+                        unsigned long consumed_count,
+                        struct lttng_ust_shm_handle *handle)
 {
        unsigned long old_id, new_id;
 
@@ -378,32 +404,36 @@ int update_read_sb_index(const struct lib_ring_buffer_config *config,
                 * old_wpage, because the value read will be confirmed by the
                 * following cmpxchg().
                 */
-               old_id = shmp(bufb->buf_wsb)[consumed_idx].id;
-               if (unlikely(!subbuffer_id_is_noref(config, old_id)))
+               old_id = shmp_index(handle, bufb->buf_wsb, consumed_idx)->id;
+               if (caa_unlikely(!subbuffer_id_is_noref(config, old_id)))
                        return -EAGAIN;
                /*
                 * Make sure the offset count we are expecting matches the one
                 * indicated by the writer.
                 */
-               if (unlikely(!subbuffer_id_compare_offset(config, old_id,
+               if (caa_unlikely(!subbuffer_id_compare_offset(config, old_id,
                                                          consumed_count)))
                        return -EAGAIN;
-               CHAN_WARN_ON(bufb->chan,
+               CHAN_WARN_ON(shmp(handle, bufb->chan),
                             !subbuffer_id_is_noref(config, bufb->buf_rsb.id));
                subbuffer_id_set_noref_offset(config, &bufb->buf_rsb.id,
                                              consumed_count);
-               new_id = uatomic_cmpxchg(&shmp(bufb->buf_wsb)[consumed_idx].id, old_id,
+               new_id = uatomic_cmpxchg(&shmp_index(handle, bufb->buf_wsb, consumed_idx)->id, old_id,
                                 bufb->buf_rsb.id);
-               if (unlikely(old_id != new_id))
+               if (caa_unlikely(old_id != new_id))
                        return -EAGAIN;
                bufb->buf_rsb.id = new_id;
        } else {
                /* No page exchange, use the writer page directly */
-               bufb->buf_rsb.id = shmp(bufb->buf_wsb)[consumed_idx].id;
+               bufb->buf_rsb.id = shmp_index(handle, bufb->buf_wsb, consumed_idx)->id;
        }
        return 0;
 }
 
+#ifndef inline_memcpy
+#define inline_memcpy(dest, src, n)    memcpy(dest, src, n)
+#endif
+
 /*
  * Use the architecture-specific memcpy implementation for constant-sized
  * inputs, but rely on an inline memcpy for length statically unknown.
@@ -418,4 +448,57 @@ do {                                                               \
                inline_memcpy(dest, src, __len);                \
 } while (0)
 
-#endif /* _LINUX_RING_BUFFER_BACKEND_INTERNAL_H */
+/*
+ * write len bytes to dest with c
+ */
+static inline
+void lib_ring_buffer_do_memset(char *dest, int c, unsigned long len)
+{
+       unsigned long i;
+
+       for (i = 0; i < len; i++)
+               dest[i] = c;
+}
+
+/* arch-agnostic implementation */
+
+static inline int lttng_ust_fls(unsigned int x)
+{
+       int r = 32;
+
+       if (!x)
+               return 0;
+       if (!(x & 0xFFFF0000U)) {
+               x <<= 16;
+               r -= 16;
+       }
+       if (!(x & 0xFF000000U)) {
+               x <<= 8;
+               r -= 8;
+       }
+       if (!(x & 0xF0000000U)) {
+               x <<= 4;
+               r -= 4;
+       }
+       if (!(x & 0xC0000000U)) {
+               x <<= 2;
+               r -= 2;
+       }
+       if (!(x & 0x80000000U)) {
+               x <<= 1;
+               r -= 1;
+       }
+       return r;
+}
+
+static inline int get_count_order(unsigned int count)
+{
+       int order;
+
+       order = lttng_ust_fls(count) - 1;
+       if (count & (count - 1))
+               order++;
+       return order;
+}
+
+#endif /* _LTTNG_RING_BUFFER_BACKEND_INTERNAL_H */
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