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authorFlorin Coras <fcoras@cisco.com>2022-03-14 21:17:25 -0700
committerFlorin Coras <florin.coras@gmail.com>2022-03-22 15:14:25 +0000
commit6bd8d3fbba74f8f80a0c09f87c6cbfddd054042f (patch)
tree51e5c3c09b6ad5b8dcd2fa77df3fb9a3dc3e7289
parentb1c0b9afacb12e8255681db25a01b94f25fed89e (diff)
session: use safe realloc for pools
Type: improvement Signed-off-by: Florin Coras <fcoras@cisco.com> Change-Id: I313c916d268c4b2b448b93e90bc67da341b803e3
-rw-r--r--src/plugins/hsi/hsi.c8
-rw-r--r--src/vnet/session/session.c30
-rw-r--r--src/vnet/session/session.h57
-rw-r--r--src/vnet/session/session_cli.c1
-rw-r--r--src/vnet/session/session_lookup.c4
-rw-r--r--src/vnet/udp/udp_input.c6
6 files changed, 25 insertions, 81 deletions
diff --git a/src/plugins/hsi/hsi.c b/src/plugins/hsi/hsi.c
index bfdb3a07fc2..9382a94de56 100644
--- a/src/plugins/hsi/hsi.c
+++ b/src/plugins/hsi/hsi.c
@@ -85,13 +85,7 @@ hsi_udp_lookup (vlib_buffer_t *b, void *ip_hdr, u8 is_ip4)
hdr->dst_port, hdr->src_port, TRANSPORT_PROTO_UDP);
}
- if (s)
- {
- session_pool_remove_peeker (s->thread_index);
- return 1;
- }
-
- return 0;
+ return s ? 1 : 0;
}
always_inline transport_connection_t *
diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index 5d070240152..f1d1a4e2cfe 100644
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -197,28 +197,31 @@ session_program_transport_ctrl_evt (session_t * s, session_evt_type_t evt)
session_send_ctrl_evt_to_thread (s, evt);
}
+static void
+session_pool_realloc_rpc (void *rpc_args)
+{
+ session_worker_t *wrk;
+ u32 thread_index;
+
+ thread_index = pointer_to_uword (rpc_args);
+ wrk = &session_main.wrk[thread_index];
+
+ pool_realloc_safe_aligned (wrk->sessions, CLIB_CACHE_LINE_BYTES);
+}
+
session_t *
session_alloc (u32 thread_index)
{
session_worker_t *wrk = &session_main.wrk[thread_index];
session_t *s;
- u8 will_expand = pool_get_will_expand (wrk->sessions);
- /* If we have peekers, let them finish */
- if (PREDICT_FALSE (will_expand && vlib_num_workers ()))
- {
- clib_rwlock_writer_lock (&wrk->peekers_rw_locks);
- pool_get_aligned (wrk->sessions, s, CLIB_CACHE_LINE_BYTES);
- clib_rwlock_writer_unlock (&wrk->peekers_rw_locks);
- }
- else
- {
- pool_get_aligned (wrk->sessions, s, CLIB_CACHE_LINE_BYTES);
- }
+ pool_get_aligned_safe (wrk->sessions, s, thread_index,
+ session_pool_realloc_rpc, CLIB_CACHE_LINE_BYTES);
clib_memset (s, 0, sizeof (*s));
s->session_index = s - wrk->sessions;
s->thread_index = thread_index;
s->app_index = APP_INVALID_INDEX;
+
return s;
}
@@ -1904,9 +1907,6 @@ session_manager_main_enable (vlib_main_t * vm)
wrk->timerfd = -1;
vec_validate (wrk->session_to_enqueue, smm->last_transport_proto_type);
- if (num_threads > 1)
- clib_rwlock_init (&smm->wrk[i].peekers_rw_locks);
-
if (!smm->no_adaptive && smm->use_private_rx_mqs)
session_wrk_enable_adaptive_mode (wrk);
}
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index 71f6d35d43b..215588edae1 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -134,9 +134,6 @@ typedef struct session_worker_
/** Head of list of pending events */
clib_llist_index_t old_head;
- /** Peekers rw lock */
- clib_rwlock_t peekers_rw_locks;
-
/** Vector of buffers to be sent */
u32 *pending_tx_buffers;
@@ -386,37 +383,9 @@ session_get_from_handle_if_valid (session_handle_t handle)
u64 session_segment_handle (session_t * s);
/**
- * Acquires a lock that blocks a session pool from expanding.
- *
- * This is typically used for safely peeking into other threads'
- * pools in order to clone elements. Lock should be dropped as soon
- * as possible by calling @ref session_pool_remove_peeker.
- *
- * NOTE: Avoid using pool_elt_at_index while the lock is held because
- * it may lead to free elt bitmap expansion/contraction!
- */
-always_inline void
-session_pool_add_peeker (u32 thread_index)
-{
- session_worker_t *wrk = &session_main.wrk[thread_index];
- if (thread_index == vlib_get_thread_index ())
- return;
- clib_rwlock_reader_lock (&wrk->peekers_rw_locks);
-}
-
-always_inline void
-session_pool_remove_peeker (u32 thread_index)
-{
- session_worker_t *wrk = &session_main.wrk[thread_index];
- if (thread_index == vlib_get_thread_index ())
- return;
- clib_rwlock_reader_unlock (&wrk->peekers_rw_locks);
-}
-
-/**
- * Get session from handle and 'lock' pool resize if not in same thread
+ * Get session from handle and avoid pool validation if no same thread
*
- * Caller should drop the peek 'lock' as soon as possible.
+ * Peekers are fine because pool grows with barrier (see @ref session_alloc)
*/
always_inline session_t *
session_get_from_handle_safe (u64 handle)
@@ -431,36 +400,24 @@ session_get_from_handle_safe (u64 handle)
}
else
{
- session_pool_add_peeker (thread_index);
- /* Don't use pool_elt_at index. See @ref session_pool_add_peeker */
+ /* Don't use pool_elt_at index to avoid pool bitmap reallocs */
return wrk->sessions + session_index_from_handle (handle);
}
}
-always_inline u32
-session_get_index (session_t * s)
-{
- return (s - session_main.wrk[s->thread_index].sessions);
-}
-
always_inline session_t *
session_clone_safe (u32 session_index, u32 thread_index)
{
+ u32 current_thread_index = vlib_get_thread_index (), new_index;
session_t *old_s, *new_s;
- u32 current_thread_index = vlib_get_thread_index ();
- /* If during the memcpy pool is reallocated AND the memory allocator
- * decides to give the old chunk of memory to somebody in a hurry to
- * scribble something on it, we have a problem. So add this thread as
- * a session pool peeker.
- */
- session_pool_add_peeker (thread_index);
new_s = session_alloc (current_thread_index);
+ new_index = new_s->session_index;
+ /* Session pools are reallocated with barrier (see @ref session_alloc) */
old_s = session_main.wrk[thread_index].sessions + session_index;
clib_memcpy_fast (new_s, old_s, sizeof (*new_s));
- session_pool_remove_peeker (thread_index);
new_s->thread_index = current_thread_index;
- new_s->session_index = session_get_index (new_s);
+ new_s->session_index = new_index;
return new_s;
}
diff --git a/src/vnet/session/session_cli.c b/src/vnet/session/session_cli.c
index 24d8cfb1e24..2003f0a7788 100644
--- a/src/vnet/session/session_cli.c
+++ b/src/vnet/session/session_cli.c
@@ -259,7 +259,6 @@ unformat_session (unformat_input_t * input, va_list * args)
if (s)
{
*result = s;
- session_pool_remove_peeker (s->thread_index);
return 1;
}
return 0;
diff --git a/src/vnet/session/session_lookup.c b/src/vnet/session/session_lookup.c
index 5cd1712f195..68f98d0f046 100644
--- a/src/vnet/session/session_lookup.c
+++ b/src/vnet/session/session_lookup.c
@@ -1046,9 +1046,7 @@ session_lookup_connection4 (u32 fib_index, ip4_address_t * lcl,
/**
* Lookup session with ip4 and transport layer information
*
- * Important note: this may look into another thread's pool table and
- * register as 'peeker'. Caller should call @ref session_pool_remove_peeker as
- * if needed as soon as possible.
+ * Important note: this may look into another thread's pool table
*
* Lookup logic is similar to that of @ref session_lookup_connection_wt4 but
* this returns a session as opposed to a transport connection and it does not
diff --git a/src/vnet/udp/udp_input.c b/src/vnet/udp/udp_input.c
index d14bdb8a298..e701ca5d12e 100644
--- a/src/vnet/udp/udp_input.c
+++ b/src/vnet/udp/udp_input.c
@@ -273,10 +273,8 @@ udp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
ASSERT (s0->session_index == uc0->c_s_index);
/*
- * Drop the peeker lock on pool resize and ask session
- * layer for a new session.
+ * Ask session layer for a new session.
*/
- session_pool_remove_peeker (s0->thread_index);
session_dgram_connect_notify (&uc0->connection,
s0->thread_index, &s0);
queue_event = 0;
@@ -286,7 +284,6 @@ udp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
}
udp_connection_enqueue (uc0, s0, &hdr0, thread_index, b[0],
queue_event, &error0);
- session_pool_remove_peeker (s0->thread_index);
}
else if (s0->session_state == SESSION_STATE_READY)
{
@@ -314,7 +311,6 @@ udp46_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
else
{
error0 = UDP_ERROR_NOT_READY;
- session_pool_remove_peeker (s0->thread_index);
}
done: