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authorFlorin Coras <fcoras@cisco.com>2022-03-26 01:25:02 -0700
committerDave Barach <openvpp@barachs.net>2022-03-26 20:10:59 +0000
commit5b47a6d014252e7fb123835da4859cfef4c95861 (patch)
tree0aa424eaf4c0ce618e03db799feaf5514ce27ade /src
parent416e1fffec997abfb5305b5ecc36da789a0676b2 (diff)
session: simplify safe pool realloc
Type: improvement Signed-off-by: Florin Coras <fcoras@cisco.com> Change-Id: I1c55c054fea6c6886d8287a9b6e264a308f89504
Diffstat (limited to 'src')
-rw-r--r--src/vnet/session/session.h104
1 files changed, 42 insertions, 62 deletions
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index 215588edae1..56e30e6533b 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -201,7 +201,10 @@ typedef struct session_main_
transport_proto_t last_transport_proto_type;
/** Number of workers at pool realloc barrier */
- u32 pool_realloc_at_barrier;
+ volatile u32 pool_realloc_at_barrier;
+
+ /** Number of workers doing reallocs */
+ volatile u32 pool_realloc_doing_work;
/** Lock to synchronize parallel forced reallocs */
clib_spinlock_t pool_realloc_lock;
@@ -774,11 +777,14 @@ STATIC_ASSERT_SIZEOF (pool_safe_realloc_header_t, sizeof (pool_header_t));
ASSERT (vlib_get_thread_index () == 0); \
vlib_worker_thread_barrier_sync (vm); \
free_elts = pool_free_elts (P); \
- max_elts = pool_max_len (P); \
- n_alloc = clib_max (2 * max_elts, POOL_REALLOC_SAFE_ELT_THRESH); \
- pool_alloc_aligned (P, free_elts + n_alloc, align); \
- clib_bitmap_validate (pool_header (P)->free_bitmap, \
- max_elts + n_alloc); \
+ if (free_elts < POOL_REALLOC_SAFE_ELT_THRESH) \
+ { \
+ max_elts = pool_max_len (P); \
+ n_alloc = clib_max (2 * max_elts, POOL_REALLOC_SAFE_ELT_THRESH); \
+ pool_alloc_aligned (P, free_elts + n_alloc, align); \
+ clib_bitmap_validate (pool_header (P)->free_bitmap, \
+ max_elts + n_alloc); \
+ } \
pool_realloc_flag (P) = 0; \
vlib_worker_thread_barrier_release (vm); \
} \
@@ -797,49 +803,40 @@ pool_program_safe_realloc (void *p, u32 thread_index,
uword_to_pointer (thread_index, void *));
}
+#define pool_realloc_all_at_barrier(_not) \
+ (*vlib_worker_threads->workers_at_barrier >= (vlib_num_workers () - _not))
+
always_inline void
-pool_realloc_maybe_wait_at_barrier (void)
+pool_realloc_wait_at_barrier (void)
{
- if (!(*vlib_worker_threads->wait_at_barrier))
- return;
+ session_main_t *sm = &session_main;
- /* Node refork required. Don't stop at the barrier from within a node */
- if (*vlib_worker_threads->node_reforks_required)
- return;
-
- clib_atomic_fetch_add (vlib_worker_threads->workers_at_barrier, 1);
+ /* Wait until main thread asks for barrier */
+ while (!(*vlib_worker_threads->wait_at_barrier))
+ ;
- while (*vlib_worker_threads->wait_at_barrier)
+ /* Stop at realloc barrier and make sure all threads are either
+ * at worker barrier or at pool realloc barrier */
+ clib_atomic_fetch_add (&sm->pool_realloc_at_barrier, 1);
+ while (!pool_realloc_all_at_barrier (sm->pool_realloc_at_barrier))
;
- clib_atomic_fetch_add (vlib_worker_threads->workers_at_barrier, -1);
+ /* Track all workers that are doing work */
+ clib_atomic_fetch_add (&sm->pool_realloc_doing_work, 1);
}
-#define pool_realloc_all_at_barrier(_not) \
- (*vlib_worker_threads->workers_at_barrier >= (vlib_num_workers () - _not))
+always_inline void
+pool_realloc_done_wait_at_barrier (void)
+{
+ session_main_t *sm = &session_main;
-#define pool_realloc_safe_force(P) \
- do \
- { \
- ALWAYS_ASSERT (*vlib_worker_threads->node_reforks_required); \
- if (pool_realloc_all_at_barrier (1)) \
- { \
- pool_alloc (P, pool_max_len (P)); \
- } \
- else \
- { \
- session_main_t *sm = &session_main; \
- clib_warning ("forced pool realloc"); \
- clib_atomic_fetch_add (&sm->pool_realloc_at_barrier, 1); \
- while (!pool_realloc_all_at_barrier (sm->pool_realloc_at_barrier)) \
- ; \
- clib_spinlock_lock (&sm->pool_realloc_lock); \
- pool_alloc (P, pool_max_len (P)); \
- clib_spinlock_unlock (&sm->pool_realloc_lock); \
- clib_atomic_fetch_add (&sm->pool_realloc_at_barrier, -1); \
- } \
- } \
- while (0)
+ /* Wait until all workers at pool realloc barrier have started reallocs */
+ while (sm->pool_realloc_doing_work < sm->pool_realloc_at_barrier)
+ ;
+
+ clib_atomic_fetch_add (&sm->pool_realloc_doing_work, -1);
+ clib_atomic_fetch_add (&sm->pool_realloc_at_barrier, -1);
+}
#define pool_needs_realloc(P) \
((!P) || \
@@ -858,30 +855,13 @@ pool_realloc_maybe_wait_at_barrier (void)
pool_alloc_aligned (P, 2 * POOL_REALLOC_SAFE_ELT_THRESH, \
align); \
} \
- else if (PREDICT_FALSE (pool_free_elts (P) < \
- POOL_REALLOC_SAFE_ELT_THRESH / 2)) \
+ else if (PREDICT_FALSE (!pool_free_elts (P))) \
{ \
- volatile typeof (P) *PP = &(P); \
pool_program_safe_realloc (P, thread_index, rpc_fn); \
- if (thread_index) \
- { \
- while (pool_realloc_flag (P)) \
- { \
- /* If refork required abort and consume existing elt */ \
- if (*vlib_worker_threads->node_reforks_required) \
- { \
- /* All workers at barrier realloc now */ \
- if (pool_realloc_all_at_barrier (1)) \
- pool_alloc_aligned (P, pool_max_len (P), align); \
- break; \
- } \
- pool_realloc_maybe_wait_at_barrier (); \
- } \
- if (pool_free_elts (P) == 0) \
- pool_realloc_safe_force (P); \
- ALWAYS_ASSERT (pool_free_elts (P) > 0); \
- } \
- (P) = *PP; \
+ pool_realloc_wait_at_barrier (); \
+ pool_alloc_aligned (P, pool_max_len (P), align); \
+ pool_realloc_done_wait_at_barrier (); \
+ ALWAYS_ASSERT (pool_free_elts (P) > 0); \
} \
else \
{ \