From aecb10b97fa97b215c415ceaa3cac4c97204922f Mon Sep 17 00:00:00 2001 From: Neale Ranns Date: Tue, 26 May 2020 13:12:17 +0000 Subject: 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 --- src/vlib/main.h | 2 +- src/vlib/threads.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ src/vlib/threads.h | 5 +++++ src/vnet/fib/ip6_fib.c | 45 +++++++++++++++++++++++++++++++-------------- 4 files changed, 84 insertions(+), 15 deletions(-) diff --git a/src/vlib/main.h b/src/vlib/main.h index d6b2d1f875f..49604e6f513 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 2f141f10d05..aebcb346f68 100644 --- a/src/vlib/threads.c +++ b/src/vlib/threads.c @@ -1434,6 +1434,18 @@ 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) { @@ -1630,6 +1642,41 @@ 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 c1188cea933..b5841ccc2e3 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 784f52c0460..8de7e2a4f9b 100644 --- a/src/vnet/fib/ip6_fib.c +++ b/src/vnet/fib/ip6_fib.c @@ -248,14 +248,29 @@ 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 @@ -311,12 +326,13 @@ 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, @@ -363,12 +379,13 @@ 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 -- cgit 1.2.3-korg