static inline u32
ooo_segment_end_pos (svm_fifo_t * f, ooo_segment_t * s)
{
- return s->start + s->length;
+ return (s->start + s->length) % f->size;
}
void
}
static inline ooo_segment_t *
-ooo_segment_get_prev (svm_fifo_t * f, ooo_segment_t * s)
+ooo_segment_prev (svm_fifo_t * f, ooo_segment_t * s)
{
if (s->prev == OOO_SEGMENT_INVALID_INDEX)
return 0;
ASSERT (offset + length <= f_distance_to (f, head, tail) || head == tail);
- offset_pos = tail + offset;
- offset_end_pos = tail + offset + length;
+ offset_pos = (tail + offset) % f->size;
+ offset_end_pos = (tail + offset + length) % f->size;
f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
s = pool_elt_at_index (f->ooo_segments, s->next);
/* If we have a previous and we overlap it, use it as starting point */
- prev = ooo_segment_get_prev (f, s);
+ prev = ooo_segment_prev (f, s);
if (prev
&& position_leq (f, offset_pos, ooo_segment_end_pos (f, prev), tail))
{
if (s->length > diff)
{
bytes = s->length - diff;
- *tail = *tail + bytes;
+ *tail = (*tail + bytes) % f->size;
ooo_segment_free (f, s_index);
break;
}
return bytes;
}
+static ooo_segment_t *
+ooo_segment_last (svm_fifo_t * f)
+{
+ ooo_segment_t *s;
+
+ if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
+ return 0;
+
+ s = svm_fifo_first_ooo_segment (f);
+ while (s->next != OOO_SEGMENT_INVALID_INDEX)
+ s = pool_elt_at_index (f->ooo_segments, s->next);
+ return s;
+}
+
void
svm_fifo_init (svm_fifo_t * f, u32 size)
{
f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
f->segment_index = SVM_FIFO_INVALID_INDEX;
f->refcnt = 1;
- f->default_chunk.start_byte = 0;
- f->default_chunk.length = f->size;
- f->default_chunk.next = f->start_chunk = f->end_chunk = &f->default_chunk;
+ f->flags = 0;
f->head_chunk = f->tail_chunk = f->ooo_enq = f->ooo_deq = f->start_chunk;
}
svm_fifo_t *
svm_fifo_create (u32 data_size_in_bytes)
{
- svm_fifo_t *f;
u32 rounded_data_size;
+ svm_fifo_chunk_t *c;
+ svm_fifo_t *f;
- /* always round fifo data size to the next highest power-of-two */
- rounded_data_size = (1 << (max_log2 (data_size_in_bytes)));
- f = clib_mem_alloc_aligned_or_null (sizeof (*f) + rounded_data_size,
- CLIB_CACHE_LINE_BYTES);
+ f = clib_mem_alloc_aligned_or_null (sizeof (*f), CLIB_CACHE_LINE_BYTES);
if (f == 0)
return 0;
clib_memset (f, 0, sizeof (*f));
+
+ /* always round fifo data size to the next highest power-of-two */
+ rounded_data_size = (1 << (max_log2 (data_size_in_bytes)));
+ c = clib_mem_alloc_aligned_or_null (sizeof (*c) + rounded_data_size,
+ CLIB_CACHE_LINE_BYTES);
+ if (!c)
+ {
+ clib_mem_free (f);
+ return 0;
+ }
+
+ c->next = c;
+ c->start_byte = 0;
+ c->length = data_size_in_bytes;
+ f->start_chunk = f->end_chunk = c;
+
svm_fifo_init (f, data_size_in_bytes);
return f;
}
return c;
}
+static inline u8
+svm_fifo_chunk_includes_pos (svm_fifo_chunk_t * c, u32 pos)
+{
+ return (pos >= c->start_byte && pos < c->start_byte + c->length);
+}
+
+/**
+ * Find chunk for given byte position
+ *
+ * @param f fifo
+ * @param pos normalized position in fifo
+ *
+ * @return chunk that includes given position or 0
+ */
+static svm_fifo_chunk_t *
+svm_fifo_find_chunk (svm_fifo_t * f, u32 pos)
+{
+ rb_tree_t *rt = &f->chunk_lookup;
+ rb_node_t *cur, *prev;
+ svm_fifo_chunk_t *c;
+
+ cur = rb_node (rt, rt->root);
+ while (pos != cur->key)
+ {
+ prev = cur;
+ if (pos < cur->key)
+ cur = rb_node_left (rt, cur);
+ else
+ cur = rb_node_right (rt, cur);
+
+ if (rb_node_is_tnil (rt, cur))
+ {
+ /* Hit tnil as a left child. Find predecessor */
+ if (pos < prev->key)
+ {
+ cur = rb_tree_predecessor (rt, prev);
+ c = uword_to_pointer (cur->opaque, svm_fifo_chunk_t *);
+ if (svm_fifo_chunk_includes_pos (c, pos))
+ return c;
+ return 0;
+ }
+ /* Hit tnil as a right child. Check if this is the one */
+ c = uword_to_pointer (prev->opaque, svm_fifo_chunk_t *);
+ if (svm_fifo_chunk_includes_pos (c, pos))
+ return c;
+
+ return 0;
+ }
+ }
+
+ if (!rb_node_is_tnil (rt, cur))
+ return uword_to_pointer (cur->opaque, svm_fifo_chunk_t *);
+ return 0;
+}
+
static inline void
-svm_fifo_size_update (svm_fifo_t * f, svm_fifo_chunk_t * c)
+svm_fifo_grow (svm_fifo_t * f, svm_fifo_chunk_t * c)
{
svm_fifo_chunk_t *prev;
u32 add_bytes = 0;
}
static void
-svm_fifo_try_size_update (svm_fifo_t * f, u32 new_head)
+svm_fifo_try_grow (svm_fifo_t * f, u32 new_head)
{
- if (new_head % f->size > f->tail % f->size)
+ if (new_head > f->tail)
return;
- svm_fifo_size_update (f, f->new_chunks);
- f->flags &= ~SVM_FIFO_F_SIZE_UPDATE;
+ svm_fifo_grow (f, f->new_chunks);
+ f->flags &= ~SVM_FIFO_F_GROW;
}
void
{
svm_fifo_chunk_t *cur, *prev;
- /* Initialize rbtree if needed and add default chunk to it */
+ /* Initialize rbtree if needed and add default chunk to it. Expectation is
+ * that this is called with the heap where the rbtree's pool is pushed. */
if (!(f->flags & SVM_FIFO_F_MULTI_CHUNK))
{
rb_tree_init (&f->chunk_lookup);
f->flags |= SVM_FIFO_F_MULTI_CHUNK;
}
- /* Initialize chunks and add to lookup rbtree. Expectation is that this is
- * called with the heap where the rbtree's pool is pushed. */
+ /* Initialize chunks and add to lookup rbtree */
cur = c;
if (f->new_chunks)
{
if (!svm_fifo_is_wrapped (f))
{
ASSERT (!f->new_chunks);
- svm_fifo_size_update (f, c);
+ svm_fifo_grow (f, c);
return;
}
if (!f->new_chunks)
{
f->new_chunks = c;
- f->flags |= SVM_FIFO_F_SIZE_UPDATE;
+ f->flags |= SVM_FIFO_F_GROW;
}
}
-static inline u8
-svm_fifo_chunk_includes_pos (svm_fifo_chunk_t * c, u32 pos)
+/**
+ * Removes chunks that are after fifo end byte
+ */
+svm_fifo_chunk_t *
+svm_fifo_collect_chunks (svm_fifo_t * f)
{
- return (pos >= c->start_byte && pos < c->start_byte + c->length);
+ svm_fifo_chunk_t *list, *cur;
+
+ f->flags &= ~SVM_FIFO_F_COLLECT_CHUNKS;
+
+ list = f->new_chunks;
+ f->new_chunks = 0;
+ cur = list;
+ while (cur)
+ {
+ rb_tree_del (&f->chunk_lookup, cur->start_byte);
+ cur = cur->next;
+ }
+
+ return list;
+}
+
+void
+svm_fifo_try_shrink (svm_fifo_t * f, u32 head, u32 tail)
+{
+ u32 len_to_shrink = 0, tail_pos, len;
+ svm_fifo_chunk_t *cur, *prev, *next, *start;
+
+ tail_pos = tail;
+ if (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX)
+ {
+ ooo_segment_t *last = ooo_segment_last (f);
+ tail_pos = ooo_segment_end_pos (f, last);
+ }
+
+ if (f->size_decrement)
+ {
+ /* Figure out available free space considering that there may be
+ * ooo segments */
+ len = clib_min (f->size_decrement, f_free_count (f, head, tail_pos));
+ f->nitems -= len;
+ f->size_decrement -= len;
+ }
+
+ /* Remove tail chunks if the following hold:
+ * - not wrapped
+ * - last used byte less than start of last chunk
+ */
+ if (tail_pos >= head && tail_pos <= f->end_chunk->start_byte)
+ {
+ /* Lookup the last position not to be removed. Since size still needs
+ * to be nitems + 1, nitems must fall within the usable space */
+ tail_pos = tail_pos > 0 ? tail_pos - 1 : tail_pos;
+ prev = svm_fifo_find_chunk (f, clib_max (f->nitems, tail_pos));
+ next = prev->next;
+ while (next != f->start_chunk)
+ {
+ cur = next;
+ next = cur->next;
+ len_to_shrink += cur->length;
+ }
+ if (len_to_shrink)
+ {
+ f->size -= len_to_shrink;
+ start = prev->next;
+ prev->next = f->start_chunk;
+ f->end_chunk = prev;
+ cur->next = f->new_chunks;
+ f->new_chunks = start;
+ }
+ }
+
+ if (!f->size_decrement && f->size == f->nitems + 1)
+ {
+ f->flags &= ~SVM_FIFO_F_SHRINK;
+ f->flags |= SVM_FIFO_F_COLLECT_CHUNKS;
+ if (f->start_chunk == f->start_chunk->next)
+ f->flags &= ~SVM_FIFO_F_MULTI_CHUNK;
+ }
}
/**
- * Find chunk for given byte position
- *
- * @param f fifo
- * @param pos normalized position in fifo
- *
- * @return chunk that includes given position or 0
+ * Request to reduce fifo size by amount of bytes
*/
-static svm_fifo_chunk_t *
-svm_fifo_find_chunk (svm_fifo_t * f, u32 pos)
+int
+svm_fifo_reduce_size (svm_fifo_t * f, u32 len, u8 try_shrink)
{
- rb_tree_t *rt = &f->chunk_lookup;
- rb_node_t *cur, *prev;
- svm_fifo_chunk_t *c;
+ svm_fifo_chunk_t *cur;
+ u32 actual_len = 0;
- cur = rb_node (rt, rt->root);
- while (pos != cur->key)
+ /* Abort if trying to reduce by more than fifo size or if
+ * fifo is undergoing resizing already */
+ if (len >= f->size || f->size > f->nitems + 1
+ || (f->flags & SVM_FIFO_F_SHRINK) || (f->flags & SVM_FIFO_F_GROW))
+ return 0;
+
+ /* last chunk that will not be removed */
+ cur = svm_fifo_find_chunk (f, f->nitems - len);
+
+ /* sum length of chunks that will be removed */
+ cur = cur->next;
+ while (cur != f->start_chunk)
{
- prev = cur;
- if (pos < cur->key)
- cur = rb_node_left (rt, cur);
- else
- cur = rb_node_right (rt, cur);
+ actual_len += cur->length;
+ cur = cur->next;
+ }
- if (rb_node_is_tnil (rt, cur))
- {
- /* Hit tnil as a left child. Find predecessor */
- if (pos < prev->key)
- {
- cur = rb_tree_predecessor (rt, prev);
- c = uword_to_pointer (cur->opaque, svm_fifo_chunk_t *);
- if (svm_fifo_chunk_includes_pos (c, pos))
- return c;
- return 0;
- }
- /* Hit tnil as a right child. Check if this is the one */
- c = uword_to_pointer (prev->opaque, svm_fifo_chunk_t *);
- if (svm_fifo_chunk_includes_pos (c, pos))
- return c;
+ ASSERT (actual_len <= len);
+ if (!actual_len)
+ return 0;
- return 0;
- }
+ f->size_decrement = actual_len;
+ f->flags |= SVM_FIFO_F_SHRINK;
+
+ if (try_shrink)
+ {
+ u32 head, tail;
+ f_load_head_tail_prod (f, &head, &tail);
+ svm_fifo_try_shrink (f, head, tail);
}
- if (!rb_node_is_tnil (rt, cur))
- return uword_to_pointer (cur->opaque, svm_fifo_chunk_t *);
- return 0;
+ return actual_len;
}
void
f_load_head_tail_cons (f, &head, &tail);
c = f->head_chunk;
- head_idx = head % f->size;
- head_idx -= c->start_byte;
+ head_idx = head - c->start_byte;
n_chunk = c->length - head_idx;
if (len <= n_chunk)
clib_memcpy_fast (&c->data[head_idx], src, len);
/* number of bytes we're going to copy */
len = clib_min (free_count, len);
- svm_fifo_copy_to_chunk (f, f->tail_chunk, tail % f->size, src, len,
- &f->tail_chunk);
- tail += len;
+ svm_fifo_copy_to_chunk (f, f->tail_chunk, tail, src, len, &f->tail_chunk);
+ tail = (tail + len) % f->size;
svm_fifo_trace_add (f, head, len, 2);
f_load_head_tail_prod (f, &head, &tail);
+ if (PREDICT_FALSE (f->flags & SVM_FIFO_F_SHRINK))
+ svm_fifo_try_shrink (f, head, tail);
+
/* free space in fifo can only increase during enqueue: SPSC */
free_count = f_free_count (f, head, tail);
f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
svm_fifo_trace_add (f, offset, len, 1);
ooo_segment_add (f, offset, head, tail, len);
- tail_idx = (tail % f->size + offset) % f->size;
+ tail_idx = (tail + offset) % f->size;
if (!svm_fifo_chunk_includes_pos (f->ooo_enq, tail_idx))
f->ooo_enq = svm_fifo_find_chunk (f, tail_idx);
return 0;
}
+/**
+ * Advance tail
+ */
+void
+svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 len)
+{
+ u32 tail;
+
+ ASSERT (len <= svm_fifo_max_enqueue_prod (f));
+ /* load-relaxed: producer owned index */
+ tail = f->tail;
+ tail = (tail + len) % f->size;
+ /* store-rel: producer owned index (paired with load-acq in consumer) */
+ clib_atomic_store_rel_n (&f->tail, tail);
+}
+
int
svm_fifo_dequeue (svm_fifo_t * f, u32 len, u8 * dst)
{
return SVM_FIFO_EEMPTY;
len = clib_min (cursize, len);
- svm_fifo_copy_from_chunk (f, f->head_chunk, head % f->size, dst, len,
- &f->head_chunk);
- head += len;
+ svm_fifo_copy_from_chunk (f, f->head_chunk, head, dst, len, &f->head_chunk);
+ head = (head + len) % f->size;
- if (PREDICT_FALSE (f->flags & SVM_FIFO_F_SIZE_UPDATE))
- svm_fifo_try_size_update (f, head);
+ if (PREDICT_FALSE (f->flags & SVM_FIFO_F_GROW))
+ svm_fifo_try_grow (f, head);
/* store-rel: consumer owned index (paired with load-acq in producer) */
clib_atomic_store_rel_n (&f->head, head);
return SVM_FIFO_EEMPTY;
len = clib_min (cursize - offset, len);
- head_idx = (head % f->size + offset) % f->size;
+ head_idx = (head + offset) % f->size;
if (!svm_fifo_chunk_includes_pos (f->ooo_deq, head_idx))
f->ooo_deq = svm_fifo_find_chunk (f, head_idx);
total_drop_bytes = clib_min (cursize, len);
/* move head */
- head += total_drop_bytes;
+ head = (head + total_drop_bytes) % f->size;
/* store-rel: consumer owned index (paired with load-acq in producer) */
clib_atomic_store_rel_n (&f->head, head);
if (PREDICT_FALSE (cursize == 0))
return SVM_FIFO_EEMPTY;
- head_idx = head % f->size;
+ head_idx = head;
if (tail < head)
{
void
svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_seg_t * fs)
{
- u32 head, head_idx;
+ u32 head;
/* consumer owned index */
head = f->head;
- head_idx = head % f->size;
- ASSERT (fs[0].data == f->head_chunk->data + head_idx);
- head += fs[0].len + fs[1].len;
+ ASSERT (fs[0].data == f->head_chunk->data + head);
+ head = (head + fs[0].len + fs[1].len) % f->size;
/* store-rel: consumer owned index (paired with load-acq in producer) */
clib_atomic_store_rel_n (&f->head, head);
}
void
svm_fifo_init_pointers (svm_fifo_t * f, u32 head, u32 tail)
{
+ head = head % f->size;
+ tail = tail % f->size;
clib_atomic_store_rel_n (&f->head, head);
clib_atomic_store_rel_n (&f->tail, tail);
if (f->flags & SVM_FIFO_F_MULTI_CHUNK)
{
svm_fifo_chunk_t *c;
- c = svm_fifo_find_chunk (f, head % f->size);
+ c = svm_fifo_find_chunk (f, head);
ASSERT (c != 0);
f->head_chunk = f->ooo_deq = c;
- c = svm_fifo_find_chunk (f, tail % f->size);
+ c = svm_fifo_find_chunk (f, tail);
ASSERT (c != 0);
f->tail_chunk = f->ooo_enq = c;
}
Code Review / vpp.git / blobdiff