summaryrefslogtreecommitdiffstats
path: root/src/vlib/buffer.c
diff options
context:
space:
mode:
authorDave Barach <dave@barachs.net>2020-04-09 17:24:07 -0400
committerFlorin Coras <florin.coras@gmail.com>2020-04-13 15:54:31 +0000
commitc74b43c80789f5e437dfe4cc491157b45a7f222e (patch)
tree0d149b8147d8225b5a872e709c6845476575fd1f /src/vlib/buffer.c
parentc54162981cdd41d65ed283df36955007552ddffe (diff)
buffers: configurable buffer fault injector
When configured at compile time via the cmake VPP_BUFFER_FAULT_INJECTOR option, the buffer allocator will appear to fail a certain fraction of the time. By default, the allocator succeeds 80% of the time. Detailed command line configuration options are available, but only when the image has been compiled with cmake option described above: vlib { buffer-alloc-success-rate [0.0 ... 1.0] buffer-alloc-success-seed <nnnn> } Modify vlib_buffer_pool_create(...) so 0 is always an invalid buffer index. Debug images: add checks for bad buffer index enqueues, and also verify that f->n_vectors doesn't accidentally map one or more instances of the frame poison pattern 0xfefefefe. Type: improvement Signed-off-by: Dave Barach <dave@barachs.net> Change-Id: Iab939858014463d1e664682805013d334d6fcbe5
Diffstat (limited to 'src/vlib/buffer.c')
-rw-r--r--src/vlib/buffer.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/src/vlib/buffer.c b/src/vlib/buffer.c
index 43b1dd63761..f5b813793a3 100644
--- a/src/vlib/buffer.c
+++ b/src/vlib/buffer.c
@@ -578,6 +578,14 @@ vlib_buffer_pool_create (vlib_main_t * vm, char *name, u32 data_size,
p = m->base + (j << m->log2_page_size) + i * alloc_size;
p += bm->ext_hdr_size;
+ /*
+ * Waste 1 buffer (maximum) so that 0 is never a valid buffer index.
+ * Allows various places to ASSERT (bi != 0). Much easier
+ * than debugging downstream crashes in successor nodes.
+ */
+ if (p == m->base)
+ continue;
+
vlib_buffer_copy_template ((vlib_buffer_t *) p, &bp->buffer_template);
bi = vlib_get_buffer_index (vm, (vlib_buffer_t *) p);
@@ -923,6 +931,24 @@ vlib_buffers_configure (vlib_main_t * vm, unformat_input_t * input)
VLIB_EARLY_CONFIG_FUNCTION (vlib_buffers_configure, "buffers");
+#if VLIB_BUFFER_ALLOC_FAULT_INJECTOR > 0
+u32
+vlib_buffer_alloc_may_fail (vlib_main_t * vm, u32 n_buffers)
+{
+ f64 r;
+
+ r = random_f64 (&vm->buffer_alloc_success_seed);
+
+ /* Fail this request? */
+ if (r > vm->buffer_alloc_success_rate)
+ n_buffers--;
+ /* 5% chance of returning nothing at all */
+ if (r > vm->buffer_alloc_success_rate && r > 0.95)
+ n_buffers = 0;
+
+ return n_buffers;
+}
+#endif
/** @endcond */
/*