src/vnet/session/segment_manager.h

/*
 * Copyright (c) 2017-2019 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef SRC_VNET_SESSION_SEGMENT_MANAGER_H_
#define SRC_VNET_SESSION_SEGMENT_MANAGER_H_

#include <svm/message_queue.h>
#include <vppinfra/lock.h>
#include <vppinfra/valloc.h>
#include <svm/fifo_segment.h>

typedef struct _segment_manager_props
{
  u32 rx_fifo_size;			/**< receive fifo size */
  u32 tx_fifo_size;			/**< transmit fifo size */
  u32 evt_q_size;			/**< event queue length */
  u32 segment_size;			/**< first segment size */
  u32 prealloc_fifos;			/**< preallocated fifo pairs */
  u32 add_segment_size;			/**< additional segment size */
  u8 add_segment:1;			/**< can add new segments flag */
  u8 use_mq_eventfd:1;			/**< use eventfds for mqs flag */
  u8 reserved:6;			/**< reserved flags */
  ssvm_segment_type_t segment_type;	/**< seg type: if set to SSVM_N_TYPES,
					     private segments are used */
} segment_manager_props_t;

typedef struct _segment_manager
{
  /** Pool of segments allocated by this manager */
  fifo_segment_t *segments;

  /** rwlock that protects the segments pool */
  clib_rwlock_t segments_rwlock;

  /** Owner app worker index */
  u32 app_wrk_index;

  /**
   * First segment should not be deleted unless segment manger is deleted.
   * This also indicates that the segment manager is the first to have been
   * allocated for the app.
   */
  u8 first_is_protected;

  /**
   * App event queue allocated in first segment
   */
  svm_msg_q_t *event_queue;
} segment_manager_t;

typedef struct segment_manager_main_init_args_
{
  u64 baseva;
  u64 size;
} segment_manager_main_init_args_t;

#define SEGMENT_MANAGER_INVALID_APP_INDEX ((u32) ~0)

segment_manager_t *segment_manager_alloc (void);
int segment_manager_init (segment_manager_t * sm, u32 first_seg_size,
			  u32 prealloc_fifo_pairs);

/**
 * Cleanup segment manager
 *
 * @param sm	segment manager to be freed
 */
void segment_manager_free (segment_manager_t * sm);

/**
 * Initiate segment manager cleanup
 *
 * @param sm	segment manager to be freed
 */
void segment_manager_init_free (segment_manager_t * sm);
segment_manager_t *segment_manager_get (u32 index);
segment_manager_t *segment_manager_get_if_valid (u32 index);
u32 segment_manager_index (segment_manager_t * sm);

int segment_manager_add_segment (segment_manager_t * sm, u32 segment_size);
void segment_manager_del_segment (segment_manager_t * sm,
				  fifo_segment_t * fs);
fifo_segment_t *segment_manager_get_segment (segment_manager_t * sm,
					     u32 segment_index);
fifo_segment_t *segment_manager_get_segment_w_handle (u64 sh);
fifo_segment_t *segment_manager_get_segment_w_lock (segment_manager_t * sm,
						    u32 segment_index);
int segment_manager_add_first_segment (segment_manager_t * sm,
				       u32 segment_size);
u64 segment_manager_make_segment_handle (u32 segment_manager_index,
					 u32 segment_index);
u64 segment_manager_segment_handle (segment_manager_t * sm,
				    fifo_segment_t * segment);
void segment_manager_segment_reader_unlock (segment_manager_t * sm);
void segment_manager_segment_writer_unlock (segment_manager_t * sm);

int segment_manager_alloc_session_fifos (segment_manager_t * sm,
					 svm_fifo_t ** rx_fifo,
					 svm_fifo_t ** tx_fifo);
int segment_manager_try_alloc_fifos (fifo_segment_t * fs,
				     u32 rx_fifo_size, u32 tx_fifo_size,
				     svm_fifo_t ** rx_fifo,
				     svm_fifo_t ** tx_fifo);
void segment_manager_dealloc_fifos (svm_fifo_t * rx_fifo,
				    svm_fifo_t * tx_fifo);

/**
 * Grows fifo owned by segment manager
 *
 * @param sm	segment manager that owns the fifo
 * @param f	fifo to be grown
 * @param size	amount of bytes to add to fifo
 * @return	0 on success, negative number otherwise
 */
int segment_manager_grow_fifo (segment_manager_t * sm, svm_fifo_t * f,
			       u32 size);

/**
 * Request to shrink fifo owned by segment manager
 *
 * If this is not called by the producer, no attempt is made to reduce the
 * size until the producer tries to enqueue more data. To collect the chunks
 * that are to be removed call @ref segment_manager_collect_fifo_chunks
 *
 * Size reduction does not affect fifo chunk boundaries. Therefore chunks are
 * not split and the amount of bytes to be removed can be equal to or less
 * than what was requested.
 *
 * @param sm		segment manager that owns the fifo
 * @param f		fifo to be shrunk
 * @param size		amount of bytes to remove from fifo
 * @param is_producer	flag that indicates is caller is the producer for the
 * 			fifo.
 * @return		actual number of bytes to be removed
 */
int segment_manager_shrink_fifo (segment_manager_t * sm, svm_fifo_t * f,
				 u32 size, u8 is_producer);

/**
 * Collect fifo chunks that are no longer used
 *
 * This should not be called unless SVM_FIFO_F_COLLECT_CHUNKS is set for
 * the fifo. The chunks are returned to the fifo segment freelist.
 *
 * @param sm		segment manager that owns the fifo
 * @param f		fifo whose chunks are to be collected
 * @return		0 on success, error otherwise
 */
int segment_manager_collect_fifo_chunks (segment_manager_t * sm,
					 svm_fifo_t * f);
u8 segment_manager_has_fifos (segment_manager_t * sm);

svm_msg_q_t *segment_manager_alloc_queue (fifo_segment_t * fs,
					  segment_manager_props_t * props);
void segment_manager_dealloc_queue (segment_manager_t * sm, svm_queue_t * q);
svm_msg_q_t *segment_manager_event_queue (segment_manager_t * sm);
u32 segment_manager_evt_q_expected_size (u32 q_size);

void segment_manager_app_detach (segment_manager_t * sm);

/**
 * Cleanup segment manager sessions
 *
 * Initiates disconnects for all sessions 'owned' by a segment manager by
 * leveraging the backpointers that fifos keep.
 *
 * @param sm	segment manager whose sessions are to be disconnected
 */
void segment_manager_del_sessions (segment_manager_t * sm);
void segment_manager_format_sessions (segment_manager_t * sm, int verbose);

void segment_manager_main_init (segment_manager_main_init_args_t * a);

segment_manager_props_t *segment_manager_props_init (segment_manager_props_t *
						     sm);

#endif /* SRC_VNET_SESSION_SEGMENT_MANAGER_H_ */
/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */