session svm: tracking segment memory usage

1. segment manager would attempt to balance the usages across
   the segments, when it allocate fifos
2. the memory presure level is determined per fifo-segment
3. updated unit test
4. updated cli output for segments

Type: feature

Signed-off-by: Ryujiro Shibuya <ryujiro.shibuya@owmobility.com>
Change-Id: I2923f3e0a43dd919196a0cb2cd55e098fde6cf66

2 files changed, 758 insertions, 0 deletions

diff --git a/src/plugins/unittest/CMakeLists.txt b/src/plugins/unittest/CMakeLists.txt
index a029e0e3259..e75b96ff265 100644
--- a/src/plugins/unittest/CMakeLists.txt
+++ b/src/plugins/unittest/CMakeLists.txt
@@ -36,6 +36,7 @@ add_vpp_plugin(unittest
   sparse_vec_test.c
   string_test.c
   svm_fifo_test.c
+  segment_manager_test.c
   tcp_test.c
   test_buffer.c
   unittest.c
diff --git a/src/plugins/unittest/segment_manager_test.c b/src/plugins/unittest/segment_manager_test.c
new file mode 100644
index 00000000000..8f362f40cb6
--- /dev/null
+++ b/src/plugins/unittest/segment_manager_test.c
@@ -0,0 +1,757 @@
+#include <vnet/vnet.h>
+#include <vnet/plugin/plugin.h>
+#include <vpp/app/version.h>
+#include <vnet/session/session.h>
+#include <vnet/session/segment_manager.h>
+#include <vnet/session/application.h>
+
+#define SEG_MGR_TEST_I(_cond, _comment, _args...)               \
+({                                                              \
+  int _evald = (_cond);                                         \
+  if (!(_evald)) {                                              \
+    fformat(stderr, "FAIL:%d: " _comment "\n",                  \
+            __LINE__, ##_args);                                 \
+  } else {                                                      \
+    fformat(stderr, "PASS:%d: " _comment "\n",                  \
+            __LINE__, ##_args);                                 \
+  }                                                             \
+  _evald;                                                       \
+})
+
+#define SEG_MGR_TEST(_cond, _comment, _args...)                 \
+{                                                               \
+    if (!SEG_MGR_TEST_I(_cond, _comment, ##_args)) {            \
+        return 1;                                               \
+    }                                                           \
+}
+
+#define ST_DBG(_comment, _args...)                              \
+    fformat(stderr,  _comment "\n",  ##_args);                  \
+
+#define SEGMENT_MANAGER_GET_INDEX_FROM_HANDLE(x) (x >> 32)
+
+/* dummy callback functions */
+static void
+dummy_session_reset_callback (session_t * s)
+{
+  clib_warning ("called...");
+}
+
+static int
+dummy_session_connected_callback (u32 app_index, u32 api_context,
+				  session_t * s, u8 is_fail)
+{
+  clib_warning ("called...");
+  return 0;
+}
+
+static int
+dummy_add_segment_callback (u32 client_index, u64 segment_handle)
+{
+  clib_warning ("called...");
+  return 0;
+}
+
+static int
+dummy_del_segment_callback (u32 client_index, u64 segment_handle)
+{
+  clib_warning ("called...");
+  return 0;
+}
+
+static void
+dummy_session_disconnect_callback (session_t * s)
+{
+  clib_warning ("called...");
+}
+
+static int
+dummy_session_accept_callback (session_t * s)
+{
+  clib_warning ("called...");
+  return 0;
+}
+
+static int
+dummy_server_rx_callback (session_t * s)
+{
+  clib_warning ("called...");
+  return -1;
+}
+
+/* *INDENT-OFF* */
+static session_cb_vft_t dummy_session_cbs = {
+  .session_reset_callback = dummy_session_reset_callback,
+  .session_connected_callback = dummy_session_connected_callback,
+  .session_accept_callback = dummy_session_accept_callback,
+  .session_disconnect_callback = dummy_session_disconnect_callback,
+  .builtin_app_rx_callback = dummy_server_rx_callback,
+  .add_segment_callback = dummy_add_segment_callback,
+  .del_segment_callback = dummy_del_segment_callback,
+};
+/* *INDENT-ON* */
+
+static char *states_str[] = {
+#define _(sym,str) str,
+  foreach_segment_mem_status
+#undef _
+};
+
+static u32 size_4KB = 4 << 10;
+static u32 size_8KB = 8 << 10;
+static u32 size_12KB = 12 << 10;
+static u32 size_16KB = 16 << 10;
+static u32 size_20KB = 20 << 10;
+static u32 size_32KB = 32 << 10;
+static u32 size_52KB = 52 << 10;
+static u32 size_64KB = 64 << 10;
+static u32 size_128KB = 128 << 10;
+static u32 size_1MB = 1 << 20;
+static u32 size_2MB = 2 << 20;
+
+
+static int
+segment_manager_test_pressure_1 (vlib_main_t * vm, unformat_input_t * input)
+{
+  int rv;
+  segment_manager_t *sm;
+  fifo_segment_t *fs0, *fs;
+  svm_fifo_t *rx_fifo, *tx_fifo;
+  uword app_seg_size = size_2MB;
+  u32 fifo_size = size_128KB;
+  u64 options[APP_OPTIONS_N_OPTIONS];
+  u8 data[size_128KB];
+
+  memset (&options, 0, sizeof (options));
+
+  vnet_app_attach_args_t attach_args = {
+    .api_client_index = ~0,
+    .options = options,
+    .namespace_id = 0,
+    .session_cb_vft = &dummy_session_cbs,
+    .name = format (0, "segment_manager_test_pressure_1"),
+  };
+
+  attach_args.options[APP_OPTIONS_SEGMENT_SIZE] = app_seg_size;
+  attach_args.options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_IS_BUILTIN;
+  attach_args.options[APP_OPTIONS_RX_FIFO_SIZE] = fifo_size;
+  attach_args.options[APP_OPTIONS_TX_FIFO_SIZE] = fifo_size;
+  rv = vnet_application_attach (&attach_args);
+  SEG_MGR_TEST ((rv == 0), "vnet_application_attach %d", rv);
+
+  sm =
+    segment_manager_get (SEGMENT_MANAGER_GET_INDEX_FROM_HANDLE
+			 (attach_args.segment_handle));
+  SEG_MGR_TEST ((sm != 0), "segment_manager_get %p", sm);
+
+  /* initial status : (0 / 2MB) */
+  fs0 = segment_manager_get_segment (sm, 0);
+  rv = fifo_segment_get_mem_status (fs0);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+
+  /* allocate a fifo : 128KB x2 */
+  rv = segment_manager_alloc_session_fifos (sm,
+					    vlib_get_thread_index (),
+					    &rx_fifo, &tx_fifo);
+  SEG_MGR_TEST ((rv == 0), "segment_manager_alloc_session_fifos %d", rv);
+
+  svm_fifo_set_size (rx_fifo, size_1MB);
+  svm_fifo_set_size (tx_fifo, size_1MB);
+
+  fs = segment_manager_get_segment (sm, rx_fifo->segment_index);
+  SEG_MGR_TEST ((fs == fs0), "fs %p", fs);
+
+  /* fill fifos (but not add chunks) */
+  svm_fifo_enqueue (rx_fifo, fifo_size - 1, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size - 1, data);
+
+  /* 256KB+ / 2048KB+ => ~12% */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* grow fifos */
+  svm_fifo_enqueue (rx_fifo, fifo_size, data);
+  svm_fifo_enqueue (rx_fifo, fifo_size, data);
+  svm_fifo_enqueue (rx_fifo, fifo_size, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size, data);
+
+  /* 8 chunks : 49% */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* grow fifos */
+  svm_fifo_enqueue (rx_fifo, fifo_size, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size, data);
+
+  /* 10 chunks : 61% */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_LOW_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* grow fifos */
+  svm_fifo_enqueue (rx_fifo, fifo_size, data);
+  svm_fifo_enqueue (rx_fifo, fifo_size, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size, data);
+
+  /* 14 chunks : 85% */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_HIGH_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+
+  /* shrink fifos */
+  svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (tx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (tx_fifo, fifo_size);
+
+  /* 10 chunks : 61% */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_LOW_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+
+  /* grow fifos */
+  svm_fifo_enqueue (rx_fifo, fifo_size, data);
+  svm_fifo_enqueue (rx_fifo, fifo_size, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size, data);
+
+  /* 14 chunks : 85% */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_HIGH_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (tx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (tx_fifo, fifo_size);
+
+
+  /* 10 chunks : 61% */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_LOW_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* shrink fifos */
+  svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (tx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (tx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (tx_fifo, fifo_size);
+  svm_fifo_dequeue_drop (tx_fifo, fifo_size);
+
+  /* 2 chunks : 12% */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+
+  vnet_app_detach_args_t detach_args = {
+    .app_index = attach_args.app_index,
+    .api_client_index = ~0,
+  };
+  rv = vnet_application_detach (&detach_args);
+  SEG_MGR_TEST ((rv == 0), "vnet_application_detach %d", rv);
+
+  return 0;
+}
+
+static int
+segment_manager_test_pressure_2 (vlib_main_t * vm, unformat_input_t * input)
+{
+  int rv, i;
+  segment_manager_t *sm;
+  fifo_segment_t *fs0, *fs;
+  svm_fifo_t *rx_fifo, *tx_fifo;
+  uword app_seg_size = size_2MB;
+  u32 fifo_size = size_4KB;
+  u64 options[APP_OPTIONS_N_OPTIONS];
+  u8 data[size_4KB];
+
+  memset (&options, 0, sizeof (options));
+
+  vnet_app_attach_args_t attach_args = {
+    .api_client_index = ~0,
+    .options = options,
+    .namespace_id = 0,
+    .session_cb_vft = &dummy_session_cbs,
+    .name = format (0, "segment_manager_test_pressure_1"),
+  };
+
+  attach_args.options[APP_OPTIONS_SEGMENT_SIZE] = app_seg_size;
+  attach_args.options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_IS_BUILTIN;
+  attach_args.options[APP_OPTIONS_RX_FIFO_SIZE] = fifo_size;
+  attach_args.options[APP_OPTIONS_TX_FIFO_SIZE] = fifo_size;
+  rv = vnet_application_attach (&attach_args);
+  SEG_MGR_TEST ((rv == 0), "vnet_application_attach %d", rv);
+
+  sm =
+    segment_manager_get (SEGMENT_MANAGER_GET_INDEX_FROM_HANDLE
+			 (attach_args.segment_handle));
+  SEG_MGR_TEST ((sm != 0), "segment_manager_get %p", sm);
+
+  /* initial status : (0 / 2MB) */
+  fs0 = segment_manager_get_segment (sm, 0);
+  fifo_segment_update_free_bytes (fs0);
+  rv = fifo_segment_get_mem_status (fs0);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+
+  /* allocate fifos : 4KB x2 */
+  rv = segment_manager_alloc_session_fifos (sm,
+					    vlib_get_thread_index (),
+					    &rx_fifo, &tx_fifo);
+  SEG_MGR_TEST ((rv == 0), "segment_manager_alloc_session_fifos %d", rv);
+
+  svm_fifo_set_size (rx_fifo, size_2MB);
+  svm_fifo_set_size (tx_fifo, size_2MB);
+
+  /* fill fifos (but not add chunks) */
+  svm_fifo_enqueue (rx_fifo, fifo_size - 1, data);
+  svm_fifo_enqueue (tx_fifo, fifo_size - 1, data);
+
+  fs = segment_manager_get_segment (sm, rx_fifo->segment_index);
+
+  /* grow fifos */
+  for (i = 0; i < 509; ++i)
+    {
+      svm_fifo_enqueue (rx_fifo, fifo_size, data);
+    }
+
+  /* 510 chunks : 100% of 2MB */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_HIGH_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* this fifo growth is expected to fail */
+  rv = svm_fifo_enqueue (rx_fifo, fifo_size, data);
+  SEG_MGR_TEST ((rv == SVM_FIFO_EGROW), "svm_fifo_enqueue %d", rv);
+
+  /* then, no-memory is detected */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_MEMORY),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* shrink fifos */
+  for (i = 0; i < 20; ++i)
+    {
+      svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+    }
+
+  /* 489 chunks : 96%, it is high-pressure level
+   * but the reached-mem-limit record is not reset
+   * so the no-memory state lasts.
+   */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_MEMORY),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* shrink fifos */
+  for (i = 0; i < 133; ++i)
+    {
+      svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+    }
+
+  /* 356 chunks : 70% of 2MB */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_LOW_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* shrink fifos */
+  for (i = 0; i < 354; ++i)
+    {
+      svm_fifo_dequeue_drop (rx_fifo, fifo_size);
+    }
+
+  /* 2 chunks : 3% of 2MB */
+  fifo_segment_update_free_bytes (fs);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+
+  vnet_app_detach_args_t detach_args = {
+    .app_index = attach_args.app_index,
+    .api_client_index = ~0,
+  };
+  rv = vnet_application_detach (&detach_args);
+  SEG_MGR_TEST ((rv == 0), "vnet_application_detach %d", rv);
+
+  return 0;
+}
+
+static int
+segment_manager_test_fifo_balanced_alloc (vlib_main_t * vm,
+					  unformat_input_t * input)
+{
+  int rv, i, fs_index;
+  segment_manager_t *sm;
+  fifo_segment_t *fs[4];
+  svm_fifo_t *rx_fifo[4], *tx_fifo[4];
+  uword app_seg_size = size_2MB;
+  u32 fifo_size = size_4KB;
+  u64 options[APP_OPTIONS_N_OPTIONS];
+  u8 data[size_4KB];
+
+  memset (&options, 0, sizeof (options));
+
+  vnet_app_attach_args_t attach_args = {
+    .api_client_index = ~0,
+    .options = options,
+    .namespace_id = 0,
+    .session_cb_vft = &dummy_session_cbs,
+    .name = format (0, "segment_manager_test_pressure_1"),
+  };
+
+  attach_args.options[APP_OPTIONS_SEGMENT_SIZE] = app_seg_size;
+  attach_args.options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_IS_BUILTIN;
+  attach_args.options[APP_OPTIONS_RX_FIFO_SIZE] = fifo_size;
+  attach_args.options[APP_OPTIONS_TX_FIFO_SIZE] = fifo_size;
+  rv = vnet_application_attach (&attach_args);
+  SEG_MGR_TEST ((rv == 0), "vnet_application_attach %d", rv);
+
+  sm =
+    segment_manager_get (SEGMENT_MANAGER_GET_INDEX_FROM_HANDLE
+			 (attach_args.segment_handle));
+  SEG_MGR_TEST ((sm != 0), "segment_manager_get %p", sm);
+
+  /* initial status : (0 / 2MB) */
+  fs[0] = segment_manager_get_segment (sm, 0);
+  rv = fifo_segment_get_mem_status (fs[0]);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* allocate fifos : 4KB x2 */
+  rv = segment_manager_alloc_session_fifos (sm,
+					    vlib_get_thread_index (),
+					    &rx_fifo[0], &tx_fifo[0]);
+  SEG_MGR_TEST ((rv == 0), "segment_manager_alloc_session_fifos %d", rv);
+  SEG_MGR_TEST ((rx_fifo[0]->segment_index == 0),
+		"segment_index %d", rx_fifo[0]->segment_index);
+  SEG_MGR_TEST ((tx_fifo[0]->segment_index == 0),
+		"segment_index %d", tx_fifo[0]->segment_index);
+
+  /* grow fifos */
+  svm_fifo_set_size (rx_fifo[0], size_1MB);
+  for (i = 0; i < 200; ++i)
+    {
+      svm_fifo_enqueue (rx_fifo[0], fifo_size, data);
+    }
+
+  /* add another 2MB segment */
+  fs_index = segment_manager_add_segment (sm, size_2MB);
+  SEG_MGR_TEST ((fs_index == 1), "fs_index %d", fs_index);
+
+  /* allocate fifos : 4KB x2
+   * expected to be allocated on the newer segment,
+   * because the usage of the first segment is high.
+   */
+  rv = segment_manager_alloc_session_fifos (sm,
+					    vlib_get_thread_index (),
+					    &rx_fifo[1], &tx_fifo[1]);
+  SEG_MGR_TEST ((rv == 0), "segment_manager_alloc_session_fifos %d", rv);
+  SEG_MGR_TEST ((rx_fifo[1]->segment_index == 1),
+		"segment_index %d", rx_fifo[1]->segment_index);
+  SEG_MGR_TEST ((tx_fifo[1]->segment_index == 1),
+		"segment_index %d", tx_fifo[1]->segment_index);
+
+  /* allocate fifos : 4KB x2
+   * expected to be allocated on the newer segment.
+   */
+  rv = segment_manager_alloc_session_fifos (sm,
+					    vlib_get_thread_index (),
+					    &rx_fifo[2], &tx_fifo[2]);
+  SEG_MGR_TEST ((rv == 0), "segment_manager_alloc_session_fifos %d", rv);
+  SEG_MGR_TEST ((rx_fifo[2]->segment_index == 1),
+		"segment_index %d", rx_fifo[2]->segment_index);
+  SEG_MGR_TEST ((tx_fifo[2]->segment_index == 1),
+		"segment_index %d", tx_fifo[2]->segment_index);
+
+  /* grow fifos, so the usage of the secong segment becomes
+   * higher than the first one.
+   */
+  svm_fifo_set_size (rx_fifo[1], size_1MB);
+  for (i = 0; i < 400; ++i)
+    {
+      svm_fifo_enqueue (rx_fifo[1], fifo_size, data);
+    }
+
+  /* allocate fifos : 4KB x2
+   * expected to be allocated on the first segment.
+   */
+  rv = segment_manager_alloc_session_fifos (sm,
+					    vlib_get_thread_index (),
+					    &rx_fifo[3], &tx_fifo[3]);
+  SEG_MGR_TEST ((rv == 0), "segment_manager_alloc_session_fifos %d", rv);
+  SEG_MGR_TEST ((rx_fifo[3]->segment_index == 0),
+		"segment_index %d", rx_fifo[3]->segment_index);
+  SEG_MGR_TEST ((tx_fifo[3]->segment_index == 0),
+		"segment_index %d", tx_fifo[3]->segment_index);
+
+
+
+  vnet_app_detach_args_t detach_args = {
+    .app_index = attach_args.app_index,
+    .api_client_index = ~0,
+  };
+  rv = vnet_application_detach (&detach_args);
+  SEG_MGR_TEST ((rv == 0), "vnet_application_detach %d", rv);
+
+  return 0;
+}
+
+static int
+segment_manager_test_fifo_ops (vlib_main_t * vm, unformat_input_t * input)
+{
+  int rv, i;
+  segment_manager_t *sm;
+  fifo_segment_t *fs;
+  svm_fifo_t *rx_fifo, *tx_fifo;
+  uword app_seg_size = size_2MB, most_grown = 0;
+  u32 fifo_size = size_4KB;
+  u32 max_dequeue = 0;
+  u64 options[APP_OPTIONS_N_OPTIONS];
+  u8 data[size_128KB];
+
+  memset (&options, 0, sizeof (options));
+
+  vnet_app_attach_args_t attach_args = {
+    .api_client_index = ~0,
+    .options = options,
+    .namespace_id = 0,
+    .session_cb_vft = &dummy_session_cbs,
+    .name = format (0, "segment_manager_test_pressure_1"),
+  };
+
+  attach_args.options[APP_OPTIONS_SEGMENT_SIZE] = app_seg_size;
+  attach_args.options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_IS_BUILTIN;
+  attach_args.options[APP_OPTIONS_RX_FIFO_SIZE] = fifo_size;
+  attach_args.options[APP_OPTIONS_TX_FIFO_SIZE] = fifo_size;
+  rv = vnet_application_attach (&attach_args);
+  SEG_MGR_TEST ((rv == 0), "vnet_application_attach %d", rv);
+
+  sm =
+    segment_manager_get (SEGMENT_MANAGER_GET_INDEX_FROM_HANDLE
+			 (attach_args.segment_handle));
+  SEG_MGR_TEST ((sm != 0), "segment_manager_get %p", sm);
+
+  /* initial status : (0 / 2MB) */
+  fs = segment_manager_get_segment (sm, 0);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* allocate fifos : 4KB x2 */
+  rv = segment_manager_alloc_session_fifos (sm,
+					    vlib_get_thread_index (),
+					    &rx_fifo, &tx_fifo);
+  SEG_MGR_TEST ((rv == 0), "segment_manager_alloc_session_fifos %d", rv);
+
+  /* check the initial fifo size : 4KB */
+  rv = svm_fifo_size (rx_fifo);
+  SEG_MGR_TEST ((rv == size_4KB), "svm_fifo_size %d", rv);
+
+  /* fill 4KB */
+  rv = svm_fifo_enqueue (rx_fifo, size_4KB, data);
+  SEG_MGR_TEST ((rv == size_4KB), "svm_fifo_enqueue %d", rv);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == size_4KB), "max_dequeue %u", max_dequeue);
+
+  /* grow the fifo size : 4KB -> 8KB */
+  svm_fifo_set_size (rx_fifo, size_8KB);
+  rv = svm_fifo_size (rx_fifo);
+  SEG_MGR_TEST ((rv == size_8KB), "svm_fifo_size %d", rv);
+
+  /* verify that fifo cannot grow larger than the fifo size */
+  /* 4KB + 8KB > 8KB, so only 4KB is queued */
+  rv = svm_fifo_enqueue (rx_fifo, size_8KB, data);
+  SEG_MGR_TEST ((rv == size_4KB), "svm_fifo_enqueue %d", rv);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == size_8KB), "max_dequeue %u", max_dequeue);
+
+  /* grow the fifo size : 8KB -> 16KB */
+  svm_fifo_set_size (rx_fifo, size_16KB);
+
+  /* 8KB + 4KB = 12KB */
+  svm_fifo_enqueue (rx_fifo, size_4KB, data);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == size_12KB), "max_dequeue %u", max_dequeue);
+
+  /* grow the fifo size : 16KB -> 32KB */
+  svm_fifo_set_size (rx_fifo, size_32KB);
+
+  /* 12KB + 8KB = 20KB */
+  svm_fifo_enqueue (rx_fifo, size_8KB, data);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == size_20KB), "max_dequeue %u", max_dequeue);
+
+  /* grow the fifo size : 32KB -> 64KB */
+  svm_fifo_set_size (rx_fifo, size_64KB);
+
+  /* 20KB + 32KB = 52KB */
+  svm_fifo_enqueue (rx_fifo, size_32KB, data);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == size_52KB), "max_dequeue %u", max_dequeue);
+
+  /* bulk enqueue */
+  for (i = 0; i < 55; ++i)
+    {
+      svm_fifo_set_size (rx_fifo, svm_fifo_size (rx_fifo) + size_32KB);
+      svm_fifo_enqueue (rx_fifo, size_32KB, data);
+    }
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == (size_52KB + size_32KB * 55)),
+		"max_dequeue %u", max_dequeue);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_HIGH_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+  most_grown = svm_fifo_size (rx_fifo);
+
+  /* dequeue */
+  svm_fifo_dequeue_drop (rx_fifo, size_20KB);
+  svm_fifo_dequeue_drop (rx_fifo, size_32KB);
+
+  /* bulk dequeue */
+  for (i = 0; i < 20; ++i)
+    svm_fifo_dequeue_drop (rx_fifo, size_32KB);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == (size_32KB * 35)), "max_dequeue %u",
+		max_dequeue);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_LOW_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* bulk dequeue */
+  for (i = 0; i < 10; ++i)
+    svm_fifo_dequeue_drop (rx_fifo, size_32KB);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == (size_32KB * 25)), "max_dequeue %u",
+		max_dequeue);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* bulk enqueue */
+  for (i = 0; i < 30; ++i)
+    svm_fifo_enqueue (rx_fifo, size_32KB, data);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == (size_32KB * 55)), "max_dequeue %u",
+		max_dequeue);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_HIGH_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* bulk dequeue */
+  for (i = 0; i < 20; ++i)
+    svm_fifo_dequeue_drop (rx_fifo, size_32KB);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == (size_32KB * 35)), "max_dequeue %u",
+		max_dequeue);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_LOW_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* bulk dequeue */
+  for (i = 0; i < 35; ++i)
+    svm_fifo_dequeue_drop (rx_fifo, size_32KB);
+  max_dequeue = svm_fifo_max_dequeue (rx_fifo);
+  SEG_MGR_TEST ((max_dequeue == 0), "max_dequeue %u", max_dequeue);
+  rv = fifo_segment_get_mem_status (fs);
+  SEG_MGR_TEST ((rv == MEMORY_PRESSURE_NO_PRESSURE),
+		"fifo_segment_get_mem_status %s", states_str[rv]);
+
+  /* (virtual) fifo size is still large as it is not updated */
+  SEG_MGR_TEST ((rx_fifo->size == most_grown), "rx_fifo->size %u",
+		rx_fifo->size);
+
+  vnet_app_detach_args_t detach_args = {
+    .app_index = attach_args.app_index,
+    .api_client_index = ~0,
+  };
+  rv = vnet_application_detach (&detach_args);
+  SEG_MGR_TEST ((rv == 0), "vnet_application_detach %d", rv);
+
+  return 0;
+}
+
+
+static clib_error_t *
+segment_manager_test (vlib_main_t * vm,
+		      unformat_input_t * input, vlib_cli_command_t * cmd_arg)
+{
+  int res = 0;
+
+  vnet_session_enable_disable (vm, 1);
+
+  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+    {
+      if (unformat (input, "pressure_levels_1"))
+	res = segment_manager_test_pressure_1 (vm, input);
+      else if (unformat (input, "pressure_levels_2"))
+	res = segment_manager_test_pressure_2 (vm, input);
+      else if (unformat (input, "alloc"))
+	res = segment_manager_test_fifo_balanced_alloc (vm, input);
+      else if (unformat (input, "fifo_ops"))
+	res = segment_manager_test_fifo_ops (vm, input);
+
+      else if (unformat (input, "all"))
+	{
+	  if ((res = segment_manager_test_pressure_1 (vm, input)))
+	    goto done;
+	  if ((res = segment_manager_test_pressure_2 (vm, input)))
+	    goto done;
+	  if ((res = segment_manager_test_fifo_balanced_alloc (vm, input)))
+	    goto done;
+	  if ((res = segment_manager_test_fifo_ops (vm, input)))
+	    goto done;
+	}
+      else
+	break;
+    }
+
+done:
+  if (res)
+    return clib_error_return (0, "Segment manager unit test failed.");
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (tcp_test_command, static) =
+{
+  .path = "test segment-manager",
+  .short_help = "test segment manager [pressure_levels_1]"
+                "[pressure_level_2][alloc][fifo_ops][all]",
+  .function = segment_manager_test,
+};
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
+