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authorFlorin Coras <fcoras@cisco.com>2019-07-02 13:07:37 -0700
committerDave Barach <openvpp@barachs.net>2019-07-03 11:26:36 +0000
commiteaacce4753c33342a6512039fe4153b15b476fb3 (patch)
treeb7465c6da3970f28db0aca7ab92b12b3c7fbaa5d /src/svm/svm_fifo.c
parentb5ef26d1ed524d1f2f59ffd5546d1c581f4c88a2 (diff)
svm: fix multi-chunk fifo alloc and add more tests
Type: fix - make sure that chunks and the rbtree are initialized if fifo segment allocates multiple chunks for the fifo. - ensure head/tail chunks are updated on all enqueue/dequeue events, including when dropping data. - more unit tests Also fixes dequeue drop updates of head chunk. Change-Id: I77f3550bc4e8b4e077f80ea87fe82b83ed013aeb Signed-off-by: Florin Coras <fcoras@cisco.com>
Diffstat (limited to 'src/svm/svm_fifo.c')
-rw-r--r--src/svm/svm_fifo.c103
1 files changed, 97 insertions, 6 deletions
diff --git a/src/svm/svm_fifo.c b/src/svm/svm_fifo.c
index 3d538293c70..56f53a3d339 100644
--- a/src/svm/svm_fifo.c
+++ b/src/svm/svm_fifo.c
@@ -404,6 +404,31 @@ svm_fifo_init (svm_fifo_t * f, u32 size)
f->head_chunk = f->tail_chunk = f->ooo_enq = f->ooo_deq = f->start_chunk;
}
+void
+svm_fifo_init_chunks (svm_fifo_t * f)
+{
+ svm_fifo_chunk_t *c, *prev;
+
+ if (f->start_chunk->next == f->start_chunk)
+ return;
+
+ f->flags |= SVM_FIFO_F_MULTI_CHUNK;
+ rb_tree_init (&f->chunk_lookup);
+ rb_tree_add2 (&f->chunk_lookup, 0, pointer_to_uword (f->start_chunk));
+
+ f->start_chunk->start_byte = 0;
+ prev = f->start_chunk;
+ c = prev->next;
+
+ while (c != f->start_chunk)
+ {
+ c->start_byte = prev->start_byte + prev->length;
+ rb_tree_add2 (&f->chunk_lookup, c->start_byte, pointer_to_uword (c));
+ prev = c;
+ c = c->next;
+ }
+}
+
/**
* Creates a fifo in the current heap. Fails vs blow up the process
*/
@@ -559,6 +584,7 @@ svm_fifo_add_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c)
* that this is called with the heap where the rbtree's pool is pushed. */
if (!(f->flags & SVM_FIFO_F_MULTI_CHUNK))
{
+ ASSERT (f->start_chunk->next == f->start_chunk);
rb_tree_init (&f->chunk_lookup);
rb_tree_add2 (&f->chunk_lookup, 0, pointer_to_uword (f->start_chunk));
f->flags |= SVM_FIFO_F_MULTI_CHUNK;
@@ -626,7 +652,7 @@ svm_fifo_collect_chunks (svm_fifo_t * f)
void
svm_fifo_try_shrink (svm_fifo_t * f, u32 head, u32 tail)
{
- u32 len_to_shrink = 0, tail_pos, len;
+ u32 len_to_shrink = 0, tail_pos, len, last_pos;
svm_fifo_chunk_t *cur, *prev, *next, *start;
tail_pos = tail;
@@ -649,13 +675,24 @@ svm_fifo_try_shrink (svm_fifo_t * f, u32 head, u32 tail)
* - not wrapped
* - last used byte less than start of last chunk
*/
- if (tail_pos >= head && tail_pos <= f->end_chunk->start_byte)
+ 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));
+ * to be nitems + 1, nitems must fall within the usable space. Also,
+ * first segment is not removable, so tail_pos can be 0. */
+ last_pos = tail_pos > 0 ? tail_pos - 1 : tail_pos;
+ prev = svm_fifo_find_chunk (f, clib_max (f->nitems, last_pos));
next = prev->next;
+ /* If tail_pos is first position in next, skip the chunk, otherwise,
+ * we must update the tail and, if fifo size is 0, even the head.
+ * We should not invalidate the tail for the caller and must not change
+ * consumer owned variables from code that's typically called by the
+ * producer */
+ if (next->start_byte == tail_pos)
+ {
+ prev = next;
+ next = next->next;
+ }
while (next != f->start_chunk)
{
cur = next;
@@ -790,7 +827,11 @@ svm_fifo_enqueue (svm_fifo_t * f, u32 len, const u8 * src)
/* collect out-of-order segments */
if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
- len += ooo_segment_try_collect (f, len, &tail);
+ {
+ len += ooo_segment_try_collect (f, len, &tail);
+ if (!svm_fifo_chunk_includes_pos (f->tail_chunk, tail))
+ f->tail_chunk = svm_fifo_find_chunk (f, tail);
+ }
/* store-rel: producer owned index (paired with load-acq in consumer) */
clib_atomic_store_rel_n (&f->tail, tail);
@@ -847,6 +888,10 @@ svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 len)
/* load-relaxed: producer owned index */
tail = f->tail;
tail = (tail + len) % f->size;
+
+ if (!svm_fifo_chunk_includes_pos (f->tail_chunk, tail))
+ f->tail_chunk = svm_fifo_find_chunk (f, tail);
+
/* store-rel: producer owned index (paired with load-acq in consumer) */
clib_atomic_store_rel_n (&f->tail, tail);
}
@@ -919,6 +964,9 @@ svm_fifo_dequeue_drop (svm_fifo_t * f, u32 len)
/* move head */
head = (head + total_drop_bytes) % f->size;
+ if (!svm_fifo_chunk_includes_pos (f->head_chunk, head))
+ f->head_chunk = svm_fifo_find_chunk (f, head);
+
/* store-rel: consumer owned index (paired with load-acq in producer) */
clib_atomic_store_rel_n (&f->head, head);
@@ -930,6 +978,10 @@ svm_fifo_dequeue_drop_all (svm_fifo_t * f)
{
/* consumer foreign index */
u32 tail = clib_atomic_load_acq_n (&f->tail);
+
+ if (!svm_fifo_chunk_includes_pos (f->head_chunk, tail))
+ f->head_chunk = svm_fifo_find_chunk (f, tail);
+
/* store-rel: consumer owned index (paired with load-acq in producer) */
clib_atomic_store_rel_n (&f->head, tail);
}
@@ -1055,6 +1107,45 @@ svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber)
}
}
+u8
+svm_fifo_is_sane (svm_fifo_t * f)
+{
+ if (f->size - 1 != f->nitems && !(f->flags & SVM_FIFO_F_SHRINK))
+ return 0;
+ if (!svm_fifo_chunk_includes_pos (f->head_chunk, f->head))
+ return 0;
+ if (!svm_fifo_chunk_includes_pos (f->tail_chunk, f->tail))
+ return 0;
+
+ if (f->start_chunk->next != f->start_chunk)
+ {
+ svm_fifo_chunk_t *c, *prev = 0, *tmp;
+ u32 size = 0;
+
+ if (!(f->flags & SVM_FIFO_F_MULTI_CHUNK))
+ return 0;
+
+ c = f->start_chunk;
+ do
+ {
+ tmp = svm_fifo_find_chunk (f, c->start_byte);
+ if (tmp != c)
+ return 0;
+ if (prev && (prev->start_byte + prev->length != c->start_byte))
+ return 0;
+ size += c->length;
+ prev = c;
+ c = c->next;
+ }
+ while (c != f->start_chunk);
+
+ if (size != f->size)
+ return 0;
+ }
+
+ return 1;
+}
+
u8 *
format_ooo_segment (u8 * s, va_list * args)
{