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authorNeale Ranns <nranns@cisco.com>2020-05-26 13:12:17 +0000
committerAndrew Yourtchenko <ayourtch@gmail.com>2020-06-12 08:22:58 +0000
commit4f3db90a6f6640cd4e9e5a80769b9bd8c07fd558 (patch)
tree2c601bb41ed24bb732165a5210916dc77d0314fc
parent3aab9be7511d64c5f094225e55572c466ccf4b80 (diff)
fib: IPv6 lookup data structure MP safe when prefixes change (VPP-1881)
Type: fix adding routes should be MP safe. When new prefixes with differrent prefix lengths are added, adjust the sorted list in an MP safe way. Change-Id: Ib73a3c84d01eb86d17f8e79ea2bd2505dd9afb3d Signed-off-by: Neale Ranns <nranns@cisco.com> (cherry picked from commit aecb10b97fa97b215c415ceaa3cac4c97204922f)
-rw-r--r--src/vlib/main.h2
-rw-r--r--src/vlib/threads.c47
-rw-r--r--src/vlib/threads.h5
-rw-r--r--src/vnet/fib/ip6_fib.c45
4 files changed, 84 insertions, 15 deletions
diff --git a/src/vlib/main.h b/src/vlib/main.h
index 20b8b464e34..a2ed9ba69f9 100644
--- a/src/vlib/main.h
+++ b/src/vlib/main.h
@@ -96,7 +96,7 @@ typedef struct vlib_main_t
u64 cpu_time_main_loop_start;
/* Incremented once for each main loop. */
- u32 main_loop_count;
+ volatile u32 main_loop_count;
/* Count of vectors processed this main loop. */
u32 main_loop_vectors_processed;
diff --git a/src/vlib/threads.c b/src/vlib/threads.c
index 07e1d79cf4c..26b9e7f8d56 100644
--- a/src/vlib/threads.c
+++ b/src/vlib/threads.c
@@ -1390,6 +1390,18 @@ vlib_worker_thread_initial_barrier_sync_and_release (vlib_main_t * vm)
*vlib_worker_threads->wait_at_barrier = 0;
}
+/**
+ * Return true if the wroker thread barrier is held
+ */
+u8
+vlib_worker_thread_barrier_held (void)
+{
+ if (vec_len (vlib_mains) < 2)
+ return (1);
+
+ return (*vlib_worker_threads->wait_at_barrier == 1);
+}
+
void
vlib_worker_thread_barrier_sync_int (vlib_main_t * vm, const char *func_name)
{
@@ -1586,6 +1598,41 @@ vlib_worker_thread_barrier_release (vlib_main_t * vm)
}
+/**
+ * Wait until each of the workers has been once around the track
+ */
+void
+vlib_worker_wait_one_loop (void)
+{
+ ASSERT (vlib_get_thread_index () == 0);
+
+ if (vec_len (vlib_mains) < 2)
+ return;
+
+ if (vlib_worker_thread_barrier_held ())
+ return;
+
+ u32 *counts = 0;
+ u32 ii;
+
+ vec_validate (counts, vec_len (vlib_mains) - 1);
+
+ /* record the current loop counts */
+ vec_foreach_index (ii, vlib_mains)
+ counts[ii] = vlib_mains[ii]->main_loop_count;
+
+ /* spin until each changes, apart from the main thread, or we'd be
+ * a while */
+ for (ii = 1; ii < vec_len (counts); ii++)
+ {
+ while (counts[ii] == vlib_mains[ii]->main_loop_count)
+ CLIB_PAUSE ();
+ }
+
+ vec_free (counts);
+ return;
+}
+
/*
* Check the frame queue to see if any frames are available.
* If so, pull the packets off the frames and put them to
diff --git a/src/vlib/threads.h b/src/vlib/threads.h
index 312323c096d..2088c5b8b7a 100644
--- a/src/vlib/threads.h
+++ b/src/vlib/threads.h
@@ -206,8 +206,13 @@ u32 vlib_frame_queue_main_init (u32 node_index, u32 frame_queue_nelts);
void vlib_worker_thread_barrier_sync_int (vlib_main_t * vm,
const char *func_name);
void vlib_worker_thread_barrier_release (vlib_main_t * vm);
+u8 vlib_worker_thread_barrier_held (void);
void vlib_worker_thread_initial_barrier_sync_and_release (vlib_main_t * vm);
void vlib_worker_thread_node_refork (void);
+/**
+ * Wait until each of the workers has been once around the track
+ */
+void vlib_worker_wait_one_loop (void);
static_always_inline uword
vlib_get_thread_index (void)
diff --git a/src/vnet/fib/ip6_fib.c b/src/vnet/fib/ip6_fib.c
index cecfcbd1560..48244e350c4 100644
--- a/src/vnet/fib/ip6_fib.c
+++ b/src/vnet/fib/ip6_fib.c
@@ -243,14 +243,29 @@ ip6_fib_table_lookup_exact_match (u32 fib_index,
static void
compute_prefix_lengths_in_search_order (ip6_fib_table_instance_t *table)
{
+ u8 *old, *prefix_lengths_in_search_order = NULL;
int i;
- vec_reset_length (table->prefix_lengths_in_search_order);
+
+ /*
+ * build the list in a scratch space then cutover so the workers
+ * can continue uninterrupted.
+ */
+ old = table->prefix_lengths_in_search_order;
+
/* Note: bitmap reversed so this is in fact a longest prefix match */
clib_bitmap_foreach (i, table->non_empty_dst_address_length_bitmap,
({
int dst_address_length = 128 - i;
- vec_add1(table->prefix_lengths_in_search_order, dst_address_length);
+ vec_add1(prefix_lengths_in_search_order, dst_address_length);
}));
+
+ table->prefix_lengths_in_search_order = prefix_lengths_in_search_order;
+
+ /*
+ * let the workers go once round the track before we free the old set
+ */
+ vlib_worker_wait_one_loop();
+ vec_free(old);
}
void
@@ -306,12 +321,13 @@ ip6_fib_table_entry_insert (u32 fib_index,
clib_bihash_add_del_24_8(&table->ip6_hash, &kv, 1);
- table->dst_address_length_refcounts[len]++;
-
- table->non_empty_dst_address_length_bitmap =
- clib_bitmap_set (table->non_empty_dst_address_length_bitmap,
- 128 - len, 1);
- compute_prefix_lengths_in_search_order (table);
+ if (0 == table->dst_address_length_refcounts[len]++)
+ {
+ table->non_empty_dst_address_length_bitmap =
+ clib_bitmap_set (table->non_empty_dst_address_length_bitmap,
+ 128 - len, 1);
+ compute_prefix_lengths_in_search_order (table);
+ }
}
u32 ip6_fib_table_fwding_lookup_with_if_index (ip6_main_t * im,
@@ -358,12 +374,13 @@ ip6_fib_table_fwding_dpo_update (u32 fib_index,
clib_bihash_add_del_24_8(&table->ip6_hash, &kv, 1);
- table->dst_address_length_refcounts[len]++;
-
- table->non_empty_dst_address_length_bitmap =
- clib_bitmap_set (table->non_empty_dst_address_length_bitmap,
- 128 - len, 1);
- compute_prefix_lengths_in_search_order (table);
+ if (0 == table->dst_address_length_refcounts[len]++)
+ {
+ table->non_empty_dst_address_length_bitmap =
+ clib_bitmap_set (table->non_empty_dst_address_length_bitmap,
+ 128 - len, 1);
+ compute_prefix_lengths_in_search_order (table);
+ }
}
void