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-rw-r--r--src/svm/svm_fifo.h79
1 files changed, 55 insertions, 24 deletions
diff --git a/src/svm/svm_fifo.h b/src/svm/svm_fifo.h
index 390e1170e27..417b0ecb672 100644
--- a/src/svm/svm_fifo.h
+++ b/src/svm/svm_fifo.h
@@ -64,9 +64,11 @@ typedef struct svm_fifo_chunk_
typedef enum svm_fifo_flag_
{
- SVM_FIFO_F_SIZE_UPDATE = 1 << 0,
- SVM_FIFO_F_MULTI_CHUNK = 1 << 1,
- SVM_FIFO_F_LL_TRACKED = 1 << 2,
+ SVM_FIFO_F_MULTI_CHUNK = 1 << 0,
+ SVM_FIFO_F_GROW = 1 << 1,
+ SVM_FIFO_F_SHRINK = 1 << 2,
+ SVM_FIFO_F_COLLECT_CHUNKS = 1 << 3,
+ SVM_FIFO_F_LL_TRACKED = 1 << 4,
} svm_fifo_flag_t;
typedef struct _svm_fifo
@@ -86,12 +88,13 @@ typedef struct _svm_fifo
u32 client_session_index; /**< app session index */
u8 master_thread_index; /**< session layer thread index */
u8 client_thread_index; /**< app worker index */
+ i8 refcnt; /**< reference count */
u32 segment_manager; /**< session layer segment manager index */
u32 segment_index; /**< segment index in segment manager */
u32 freelist_index; /**< aka log2(allocated_size) - const. */
- i8 refcnt; /**< reference count */
struct _svm_fifo *next; /**< next in freelist/active chain */
struct _svm_fifo *prev; /**< prev in active chain */
+ u32 size_decrement; /**< bytes to remove from fifo */
CLIB_CACHE_LINE_ALIGN_MARK (consumer);
u32 head; /**< fifo head position/byte */
@@ -172,7 +175,8 @@ f_load_head_tail_prod (svm_fifo_t * f, u32 * head, u32 * tail)
*head = clib_atomic_load_acq_n (&f->head);
}
-/* Load head and tail independent of producer/consumer role
+/**
+ * Load head and tail independent of producer/consumer role
*
* Internal function.
*/
@@ -230,6 +234,13 @@ f_free_count (svm_fifo_t * f, u32 head, u32 tail)
}
/**
+ * Try to shrink fifo size.
+ *
+ * Internal function.
+ */
+void svm_fifo_try_shrink (svm_fifo_t * f, u32 head, u32 tail);
+
+/**
* Create fifo of requested size
*
* Allocates fifo on current heap.
@@ -267,6 +278,31 @@ svm_fifo_chunk_t *svm_fifo_chunk_alloc (u32 size);
*/
void svm_fifo_add_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c);
/**
+ * Request to reduce fifo size by amount of bytes
+ *
+ * Because the producer might be enqueuing data when this is called, the
+ * actual size update is only applied when producer tries to enqueue new
+ * data, unless @param try_shrink is set.
+ *
+ * @param f fifo
+ * @param len number of bytes to remove from fifo. The actual number
+ * of bytes to be removed will be less or equal to this
+ * value.
+ * @param try_shrink flg to indicate if it's safe to try to shrink fifo
+ * size. It should be set only if this is called by the
+ * producer of if the producer is not using the fifo
+ * @return actual length fifo size will be reduced by
+ */
+int svm_fifo_reduce_size (svm_fifo_t * f, u32 len, u8 try_shrink);
+/**
+ * Removes chunks that are after fifo end byte
+ *
+ * Needs to be called with segment heap pushed.
+ *
+ * @param f fifo
+ */
+svm_fifo_chunk_t *svm_fifo_collect_chunks (svm_fifo_t * f);
+/**
* Free fifo and associated state
*
* @param f fifo
@@ -333,6 +369,16 @@ int svm_fifo_enqueue (svm_fifo_t * f, u32 len, const u8 * src);
*/
int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset, u32 len,
u8 * src);
+
+/**
+ * Advance tail pointer
+ *
+ * Useful for moving tail pointer after external enqueue.
+ *
+ * @param f fifo
+ * @param len number of bytes to add to tail
+ */
+void svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 len);
/**
* Overwrite fifo head with new data
*
@@ -551,6 +597,8 @@ svm_fifo_max_enqueue_prod (svm_fifo_t * f)
{
u32 head, tail;
f_load_head_tail_prod (f, &head, &tail);
+ if (PREDICT_FALSE (f->flags & SVM_FIFO_F_SHRINK))
+ svm_fifo_try_shrink (f, head, tail);
return f_free_count (f, head, tail);
}
@@ -565,6 +613,8 @@ svm_fifo_max_enqueue (svm_fifo_t * f)
{
u32 head, tail;
f_load_head_tail_all_acq (f, &head, &tail);
+ if (PREDICT_FALSE (f->flags & SVM_FIFO_F_SHRINK))
+ svm_fifo_try_shrink (f, head, tail);
return f_free_count (f, head, tail);
}
@@ -590,25 +640,6 @@ svm_fifo_max_write_chunk (svm_fifo_t * f)
return tail > head ? f->size - tail : f_free_count (f, head, tail);
}
-/**
- * Advance tail pointer
- *
- * Useful for moving tail pointer after external enqueue.
- *
- * @param f fifo
- * @param len number of bytes to add to tail
- */
-static inline void
-svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 len)
-{
- ASSERT (len <= svm_fifo_max_enqueue_prod (f));
- /* load-relaxed: producer owned index */
- u32 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);
-}
-
static inline u8 *
svm_fifo_head (svm_fifo_t * f)
{