svm: fix inadequate atomic load for chunk mgr

[vpp.git] / src / svm / fifo_segment.c

diff --git a/src/svm/fifo_segment.c b/src/svm/fifo_segment.c
index cde906f..cb1f08a 100644 (file)
--- a/src/svm/fifo_segment.c
+++ b/src/svm/fifo_segment.c
@@ -154,7 +154,7 @@ fss_chunk_free_list_push (fifo_segment_header_t *fsh,
 
   csp = fs_chunk_sptr (fsh, c);
   ASSERT (csp <= FS_CL_HEAD_MASK);
-  old_head = clib_atomic_load_relax_n (&fss->free_chunks[fl_index]);
+  old_head = clib_atomic_load_acq_n (&fss->free_chunks[fl_index]);
 
   do
     {
@@ -174,7 +174,7 @@ fss_chunk_free_list_push_list (fifo_segment_header_t *fsh,
 
   headsp = fs_chunk_sptr (fsh, head);
   ASSERT (headsp <= FS_CL_HEAD_MASK);
-  old_head = clib_atomic_load_relax_n (&fss->free_chunks[fl_index]);
+  old_head = clib_atomic_load_acq_n (&fss->free_chunks[fl_index]);
 
   do
     {
@@ -194,7 +194,7 @@ fss_chunk_free_list_pop (fifo_segment_header_t *fsh, fifo_segment_slice_t *fss,
 
   ASSERT (fss_chunk_fl_index_is_valid (fss, fl_index));
 
-  old_head = clib_atomic_load_relax_n (&fss->free_chunks[fl_index]);
+  old_head = clib_atomic_load_acq_n (&fss->free_chunks[fl_index]);
 
   /* Lock-free stacks are affected by ABA if a side allocates a chunk and
    * shortly thereafter frees it. To circumvent that, reuse the upper bits
@@ -694,7 +694,8 @@ free_list:
       if (data_bytes <= fss_fl_chunk_bytes (fss) + n_free)
        {
          u32 min_size = FIFO_SEGMENT_MIN_FIFO_SIZE;
-
+         if (n_free < min_size)
+           goto done;
          batch = (data_bytes - fss_fl_chunk_bytes (fss)) / min_size;
          batch = clib_min (batch + 1, n_free / min_size);
          if (fsh_try_alloc_chunk_batch (fsh, fss, 0, batch))