*/
static inline int
segment_manager_add_segment_inline (segment_manager_t *sm, uword segment_size,
- u8 notify_app, u8 flags)
+ u8 notify_app, u8 flags, u8 need_lock)
{
segment_manager_main_t *smm = &sm_main;
segment_manager_props_t *props;
/*
* Allocate fifo segment and grab lock if needed
*/
- if (vlib_num_workers ())
+ if (need_lock)
clib_rwlock_writer_lock (&sm->segments_rwlock);
pool_get_zero (sm->segments, fs);
}
done:
- if (vlib_num_workers ())
+ if (need_lock)
clib_rwlock_writer_unlock (&sm->segments_rwlock);
return fs_index;
segment_manager_add_segment (segment_manager_t *sm, uword segment_size,
u8 notify_app)
{
- return segment_manager_add_segment_inline (sm, segment_size, notify_app, 0);
+ return segment_manager_add_segment_inline (sm, segment_size, notify_app,
+ 0 /* flags */, 0 /* need_lock */);
}
int
segment_manager_add_segment2 (segment_manager_t *sm, uword segment_size,
u8 flags)
{
- return segment_manager_add_segment_inline (sm, segment_size, 0, flags);
+ return segment_manager_add_segment_inline (sm, segment_size, 0, flags,
+ vlib_num_workers ());
}
/**
clib_rwlock_reader_unlock (&sm->segments_rwlock);
}
-void
-segment_manager_segment_writer_unlock (segment_manager_t * sm)
-{
- clib_rwlock_writer_unlock (&sm->segments_rwlock);
-}
-
segment_manager_t *
segment_manager_alloc (void)
{
return 0;
}
+static inline int
+sm_lookup_segment_and_alloc_fifos (segment_manager_t *sm,
+ segment_manager_props_t *props,
+ u32 thread_index, svm_fifo_t **rx_fifo,
+ svm_fifo_t **tx_fifo)
+{
+ uword free_bytes, max_free_bytes;
+ fifo_segment_t *cur, *fs = 0;
+ u32 fs_index;
+ int rv;
+
+ max_free_bytes = props->rx_fifo_size + props->tx_fifo_size - 1;
+
+ pool_foreach (cur, sm->segments)
+ {
+ if (fifo_segment_flags (cur) & FIFO_SEGMENT_F_CUSTOM_USE)
+ continue;
+ free_bytes = fifo_segment_available_bytes (cur);
+ if (free_bytes > max_free_bytes)
+ {
+ max_free_bytes = free_bytes;
+ fs = cur;
+ }
+ }
+
+ if (PREDICT_FALSE (!fs))
+ return SESSION_E_SEG_NO_SPACE;
+
+ fs_index = segment_manager_segment_index (sm, fs);
+ rv = segment_manager_try_alloc_fifos (fs, thread_index, props->rx_fifo_size,
+ props->tx_fifo_size, rx_fifo, tx_fifo);
+
+ return rv ? SESSION_E_SEG_NO_SPACE : fs_index;
+}
+
+static int
+sm_lock_and_alloc_segment_and_fifos (segment_manager_t *sm,
+ segment_manager_props_t *props,
+ u32 thread_index, svm_fifo_t **rx_fifo,
+ svm_fifo_t **tx_fifo)
+{
+ int new_fs_index, rv;
+ fifo_segment_t *fs;
+
+ if (!props->add_segment)
+ return SESSION_E_SEG_NO_SPACE;
+
+ clib_rwlock_writer_lock (&sm->segments_rwlock);
+
+ /* Make sure there really is no free space. Another worker might've freed
+ * some fifos or allocated a segment */
+ rv = sm_lookup_segment_and_alloc_fifos (sm, props, thread_index, rx_fifo,
+ tx_fifo);
+ if (rv > 0)
+ goto done;
+
+ new_fs_index =
+ segment_manager_add_segment (sm, 0 /* segment_size*/, 1 /* notify_app */);
+ if (new_fs_index < 0)
+ {
+ rv = SESSION_E_SEG_CREATE;
+ goto done;
+ }
+ fs = segment_manager_get_segment (sm, new_fs_index);
+ rv = segment_manager_try_alloc_fifos (fs, thread_index, props->rx_fifo_size,
+ props->tx_fifo_size, rx_fifo, tx_fifo);
+ if (rv)
+ {
+ clib_warning ("Added a segment, still can't allocate a fifo");
+ rv = SESSION_E_SEG_NO_SPACE2;
+ goto done;
+ }
+
+ rv = new_fs_index;
+
+done:
+
+ clib_rwlock_writer_unlock (&sm->segments_rwlock);
+
+ return rv;
+}
+
int
segment_manager_alloc_session_fifos (segment_manager_t * sm,
u32 thread_index,
svm_fifo_t ** rx_fifo,
svm_fifo_t ** tx_fifo)
{
- int alloc_fail = 1, rv = 0, new_fs_index;
- uword free_bytes, max_free_bytes = 0;
segment_manager_props_t *props;
- fifo_segment_t *fs = 0, *cur;
- u32 sm_index, fs_index;
+ u32 sm_index;
+ int fs_index;
props = segment_manager_properties_get (sm);
+ sm_index = segment_manager_index (sm);
/*
- * Find the first free segment to allocate the fifos in
+ * Fast path: find the first segment with enough free space and
+ * try to allocate the fifos. Done with reader lock
*/
segment_manager_segment_reader_lock (sm);
- pool_foreach (cur, sm->segments) {
- if (fifo_segment_flags (cur) & FIFO_SEGMENT_F_CUSTOM_USE)
- continue;
- free_bytes = fifo_segment_available_bytes (cur);
- if (free_bytes > max_free_bytes)
- {
- max_free_bytes = free_bytes;
- fs = cur;
- }
- }
-
- if (fs)
- {
- alloc_fail = segment_manager_try_alloc_fifos (fs, thread_index,
- props->rx_fifo_size,
- props->tx_fifo_size,
- rx_fifo, tx_fifo);
- /* On success, keep lock until fifos are initialized */
- if (!alloc_fail)
- goto alloc_success;
- }
+ fs_index = sm_lookup_segment_and_alloc_fifos (sm, props, thread_index,
+ rx_fifo, tx_fifo);
segment_manager_segment_reader_unlock (sm);
/*
- * Allocation failed, see if we can add a new segment
+ * Slow path: if no fifo segment or alloc fail grab writer lock and try
+ * to allocate new segment
*/
- if (props->add_segment)
+ if (PREDICT_FALSE (fs_index < 0))
{
- if ((new_fs_index = segment_manager_add_segment (sm, 0, 1)) < 0)
- {
- clib_warning ("Failed to add new segment");
- return SESSION_E_SEG_CREATE;
- }
- fs = segment_manager_get_segment_w_lock (sm, new_fs_index);
- alloc_fail = segment_manager_try_alloc_fifos (fs, thread_index,
- props->rx_fifo_size,
- props->tx_fifo_size,
- rx_fifo, tx_fifo);
- if (alloc_fail)
- {
- clib_warning ("Added a segment, still can't allocate a fifo");
- segment_manager_segment_reader_unlock (sm);
- return SESSION_E_SEG_NO_SPACE2;
- }
+ fs_index = sm_lock_and_alloc_segment_and_fifos (sm, props, thread_index,
+ rx_fifo, tx_fifo);
+ if (fs_index < 0)
+ return fs_index;
}
- else
- {
- SESSION_DBG ("Can't add new seg and no space to allocate fifos!");
- return SESSION_E_SEG_NO_SPACE;
- }
-
-alloc_success:
- ASSERT (rx_fifo && tx_fifo);
- sm_index = segment_manager_index (sm);
- fs_index = segment_manager_segment_index (sm, fs);
(*tx_fifo)->segment_manager = sm_index;
(*rx_fifo)->segment_manager = sm_index;
(*tx_fifo)->segment_index = fs_index;
(*rx_fifo)->segment_index = fs_index;
- /* Drop the lock after app is notified */
- segment_manager_segment_reader_unlock (sm);
-
- return rv;
+ return 0;
}
void
Code Review / vpp.git / blobdiff