src/svm/fifo_segment.c - fdio/vpp - Gitiles

 /*
  * Copyright (c) 2016-2019 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.
  */

 #include <svm/fifo_segment.h>

 /**
  * Fifo segment free space
  *
  * Queries the underlying memory manager, dlmalloc, for free space. Since this
  * ends up walking the internal data structures, it should not be called
  * indiscriminately.
  *
  * @param fs		fifo segment
  * @return		number of free bytes
  */
 static u32
 fs_free_space (fifo_segment_t * fs)
 {
   struct dlmallinfo dlminfo;

   dlminfo = mspace_mallinfo (fs->ssvm.sh->heap);
   return dlminfo.fordblks;
 }

 /**
  * Initialize fifo segment shared header
  */
 int
 fifo_segment_init (fifo_segment_t * fs)
 {
   fifo_segment_header_t *fsh;
   ssvm_shared_header_t *sh;
   void *oldheap;

   sh = fs->ssvm.sh;
   oldheap = ssvm_push_heap (sh);

   fsh = clib_mem_alloc (sizeof (*fsh));
   clib_memset (fsh, 0, sizeof (*fsh));
   fs->h = sh->opaque[0] = fsh;

   ssvm_pop_heap (oldheap);

   fsh->n_free_bytes = fs_free_space (fs);
   sh->ready = 1;
   return (0);
 }

 /**
  * Create a fifo segment and initialize as master
  */
 int
 fifo_segment_create (fifo_segment_main_t * sm, fifo_segment_create_args_t * a)
 {
   fifo_segment_t *fs;
   uword baseva;
   int rv;

   /* Allocate a fresh segment */
   pool_get_zero (sm->segments, fs);

   baseva = a->segment_type == SSVM_SEGMENT_PRIVATE ? ~0ULL : sm->next_baseva;
   fs->ssvm.ssvm_size = a->segment_size;
   fs->ssvm.i_am_master = 1;
   fs->ssvm.my_pid = getpid ();
   fs->ssvm.name = format (0, "%s%c", a->segment_name, 0);
   fs->ssvm.requested_va = baseva;

   if ((rv = ssvm_master_init (&fs->ssvm, a->segment_type)))
     {
       pool_put (sm->segments, fs);
       return (rv);
     }

   /* Note: requested_va updated due to seg base addr randomization */
   sm->next_baseva = fs->ssvm.sh->ssvm_va + fs->ssvm.ssvm_size;

   fifo_segment_init (fs);
   vec_add1 (a->new_segment_indices, fs - sm->segments);
   return (0);
 }

 /**
  * Attach as slave to a fifo segment
  */
 int
 fifo_segment_attach (fifo_segment_main_t * sm, fifo_segment_create_args_t * a)
 {
   fifo_segment_t *s;
   int rv;

   pool_get_zero (sm->segments, s);

   s->ssvm.ssvm_size = a->segment_size;
   s->ssvm.my_pid = getpid ();
   s->ssvm.name = format (0, "%s%c", a->segment_name, 0);
   s->ssvm.requested_va = sm->next_baseva;
   if (a->segment_type == SSVM_SEGMENT_MEMFD)
     s->ssvm.fd = a->memfd_fd;
   else
     s->ssvm.attach_timeout = sm->timeout_in_seconds;

   if ((rv = ssvm_slave_init (&s->ssvm, a->segment_type)))
     {
       _vec_len (s) = vec_len (s) - 1;
       return (rv);
     }

   /* Fish the segment header */
   s->h = s->ssvm.sh->opaque[0];

   vec_add1 (a->new_segment_indices, s - sm->segments);
   return (0);
 }

 void
 fifo_segment_delete (fifo_segment_main_t * sm, fifo_segment_t * s)
 {
   ssvm_delete (&s->ssvm);
   clib_memset (s, 0xfe, sizeof (*s));
   pool_put (sm->segments, s);
 }

 u32
 fifo_segment_index (fifo_segment_main_t * sm, fifo_segment_t * s)
 {
   return s - sm->segments;
 }

 void *
 svm_fifo_segment_heap (fifo_segment_t * seg)
 {
   return seg->ssvm.sh->heap;
 }

 fifo_segment_t *
 fifo_segment_get_segment (fifo_segment_main_t * sm, u32 segment_index)
 {
   return pool_elt_at_index (sm->segments, segment_index);
 }

 void
 fifo_segment_info (fifo_segment_t * seg, char **address, size_t * size)
 {
   *address = (char *) seg->ssvm.sh->ssvm_va;
   *size = seg->ssvm.ssvm_size;
 }

 void
 fifo_segment_main_init (fifo_segment_main_t * sm, u64 baseva,
 			u32 timeout_in_seconds)
 {
   sm->next_baseva = baseva;
   sm->timeout_in_seconds = timeout_in_seconds;
 }

 static inline u32
 fs_freelist_for_size (u32 size)
 {
   return max_log2 (size) - max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE);
 }

 static inline u32
 fs_freelist_index_to_size (u32 fl_index)
 {
   return 1 << (fl_index + max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE));
 }

 static inline int
 fs_chunk_size_is_valid (u32 size)
 {
   /*
    * 4K minimum. It's not likely that anything good will happen
    * with a smaller FIFO.
    */
   return size >= FIFO_SEGMENT_MIN_FIFO_SIZE
     && size <= FIFO_SEGMENT_MAX_FIFO_SIZE;
 }

 static svm_fifo_t *
 fs_try_alloc_fifo_freelist (fifo_segment_t * fs, u32 fl_index, u32 data_bytes)
 {
   fifo_segment_header_t *fsh = fs->h;
   svm_fifo_chunk_t *c;
   svm_fifo_t *f;

   f = fsh->free_fifos;
   c = fsh->free_chunks[fl_index];

   if (!f || !c)
     return 0;

   fsh->free_fifos = f->next;
   fsh->free_chunks[fl_index] = c->next;
   c->next = c;
   c->start_byte = 0;
   c->length = data_bytes;
   memset (f, 0, sizeof (*f));
   f->start_chunk = c;
   f->end_chunk = c;

   fsh->n_fl_chunk_bytes -= fs_freelist_index_to_size (fl_index);
   return f;
 }

 static svm_fifo_t *
 fs_try_alloc_fifo_freelist_multi_chunk (fifo_segment_t * fs, u32 data_bytes)
 {
   svm_fifo_chunk_t *c, *first = 0, *last = 0;
   fifo_segment_header_t *fsh = fs->h;
   u32 fl_index, fl_size, n_alloc = 0;
   svm_fifo_t *f;

   f = fsh->free_fifos;
   if (!f)
     {
       void *oldheap = ssvm_push_heap (fs->ssvm.sh);
       f = clib_mem_alloc_aligned (sizeof (*f), CLIB_CACHE_LINE_BYTES);
       ssvm_pop_heap (oldheap);
       if (!f)
 	return 0;
       memset (f, 0, sizeof (*f));
     }

   fl_index = fs_freelist_for_size (data_bytes) - 1;
   vec_validate_init_empty (fsh->free_chunks, fl_index, 0);
   fl_size = fs_freelist_index_to_size (fl_index);

   while (data_bytes)
     {
       c = fsh->free_chunks[fl_index];
       if (c)
 	{
 	  fsh->free_chunks[fl_index] = c->next;
 	  if (!last)
 	    last = c;
 	  c->next = first;
 	  first = c;
 	  n_alloc += c->length;
 	  c->length = clib_min (fl_size, data_bytes);
 	  data_bytes -= c->length;
 	}
       else
 	{
 	  ASSERT (fl_index > 0);
 	  fl_index -= 1;
 	  fl_size = fl_size >> 1;
 	}
     }
   f->start_chunk = first;
   f->end_chunk = last;
   last->next = first;
   fsh->n_fl_chunk_bytes -= n_alloc;
   return f;
 }

 static int
 fs_try_alloc_fifo_batch (fifo_segment_t * fs, u32 fl_index, u32 batch_size)
 {
   fifo_segment_header_t *fsh = fs->h;
   u32 size, hdrs, rounded_data_size;
   svm_fifo_chunk_t *c;
   svm_fifo_t *f;
   void *oldheap;
   u8 *fmem;
   int i;

   vec_validate_init_empty (fsh->free_chunks, fl_index, 0);
   rounded_data_size = fs_freelist_index_to_size (fl_index);
   hdrs = sizeof (*f) + sizeof (*c);
   size = (hdrs + rounded_data_size) * batch_size;

   oldheap = ssvm_push_heap (fs->ssvm.sh);
   fmem = clib_mem_alloc_aligned_at_offset (size, CLIB_CACHE_LINE_BYTES,
 					   0 /* align_offset */ ,
 					   0 /* os_out_of_memory */ );
   ssvm_pop_heap (oldheap);

   /* Out of space.. */
   if (fmem == 0)
     return -1;

   /* Carve fifo + chunk space */
   for (i = 0; i < batch_size; i++)
     {
       f = (svm_fifo_t *) fmem;
       memset (f, 0, sizeof (*f));
       f->next = fsh->free_fifos;
       fsh->free_fifos = f;
       c = (svm_fifo_chunk_t *) (fmem + sizeof (*f));
       c->start_byte = 0;
       c->length = rounded_data_size;
       c->next = fsh->free_chunks[fl_index];
       fsh->free_chunks[fl_index] = c;
       fmem += hdrs + rounded_data_size;
     }

   fsh->n_fl_chunk_bytes += batch_size * rounded_data_size;
   fsh->n_free_bytes -= size;

   return 0;
 }

 /**
  * Try to allocate new fifo
  *
  * Tries the following steps in order:
  * - grab fifo and chunk from freelists
  * - batch fifo and chunk allocation
  * - single fifo allocation
  * - grab multiple fifo chunks from freelists
  */
 static svm_fifo_t *
 fs_try_alloc_fifo (fifo_segment_t * fs, u32 data_bytes)
 {
   fifo_segment_header_t *fsh = fs->h;
   u32 fifo_sz, fl_index;
   svm_fifo_t *f = 0;

   fl_index = fs_freelist_for_size (data_bytes);
   vec_validate_init_empty (fsh->free_chunks, fl_index, 0);
   fifo_sz = sizeof (svm_fifo_t) + sizeof (svm_fifo_chunk_t);
   fifo_sz += 1 << max_log2 (data_bytes);

   if (fsh->free_fifos && fsh->free_chunks[fl_index])
     {
       f = fs_try_alloc_fifo_freelist (fs, fl_index, data_bytes);
       if (f)
 	goto done;
     }
   if (fifo_sz * FIFO_SEGMENT_ALLOC_BATCH_SIZE < fsh->n_free_bytes)
     {
       if (fs_try_alloc_fifo_batch (fs, fl_index,
 				   FIFO_SEGMENT_ALLOC_BATCH_SIZE))
 	goto done;

       f = fs_try_alloc_fifo_freelist (fs, fl_index, data_bytes);
       goto done;
     }
   if (fifo_sz <= fsh->n_free_bytes)
     {
       void *oldheap = ssvm_push_heap (fs->ssvm.sh);
       f = svm_fifo_create (data_bytes);
       ssvm_pop_heap (oldheap);
       if (f)
 	{
 	  fsh->n_free_bytes -= fifo_sz;
 	  goto done;
 	}
     }
   if (data_bytes <= fsh->n_fl_chunk_bytes)
     f = fs_try_alloc_fifo_freelist_multi_chunk (fs, data_bytes);

 done:

   return f;
 }

 /**
  * Allocate fifo in fifo segment
  */
 svm_fifo_t *
 fifo_segment_alloc_fifo (fifo_segment_t * fs, u32 data_bytes,
 			 fifo_segment_ftype_t ftype)
 {
   fifo_segment_header_t *fsh;
   svm_fifo_t *f = 0;

   if (!fs_chunk_size_is_valid (data_bytes))
     {
       clib_warning ("fifo size out of range %d", data_bytes);
       return 0;
     }

   fsh = fs->h;
   ssvm_lock_non_recursive (fs->ssvm.sh, 1);

   f = fs_try_alloc_fifo (fs, data_bytes);
   if (!f)
     goto done;

   /* (re)initialize the fifo, as in svm_fifo_create */
   svm_fifo_init (f, data_bytes);

   /* If rx fifo type add to active fifos list. When cleaning up segment,
    * we need a list of active sessions that should be disconnected. Since
    * both rx and tx fifos keep pointers to the session, it's enough to track
    * only one. */
   if (ftype == FIFO_SEGMENT_RX_FIFO)
     {
       if (fsh->fifos)
 	{
 	  fsh->fifos->prev = f;
 	  f->next = fsh->fifos;
 	}
       fsh->fifos = f;
       f->flags |= SVM_FIFO_F_LL_TRACKED;
     }
   fsh->n_active_fifos++;

 done:
   ssvm_unlock_non_recursive (fs->ssvm.sh);
   return (f);
 }

 /**
  * Free fifo allocated in fifo segment
  */
 void
 fifo_segment_free_fifo (fifo_segment_t * fs, svm_fifo_t * f)
 {
   svm_fifo_chunk_t *cur, *next;
   fifo_segment_header_t *fsh;
   ssvm_shared_header_t *sh;
   void *oldheap;
   int fl_index;

   ASSERT (f->refcnt > 0);

   if (--f->refcnt > 0)
     return;

   sh = fs->ssvm.sh;
   fsh = fs->h;

   ssvm_lock_non_recursive (sh, 2);

   /* Remove from active list. Only rx fifos are tracked */
   if (f->flags & SVM_FIFO_F_LL_TRACKED)
     {
       if (f->prev)
 	f->prev->next = f->next;
       else
 	fsh->fifos = f->next;
       if (f->next)
 	f->next->prev = f->prev;
       f->flags &= ~SVM_FIFO_F_LL_TRACKED;
     }

   /* Add to free list */
   f->next = fsh->free_fifos;
   f->prev = 0;
   fsh->free_fifos = f;

   /* Free fifo chunks */
   cur = f->start_chunk;
   do
     {
       next = cur->next;
       fl_index = fs_freelist_for_size (cur->length);
       ASSERT (fl_index < vec_len (fsh->free_chunks));
       cur->next = fsh->free_chunks[fl_index];
       fsh->free_chunks[fl_index] = cur;
       fsh->n_fl_chunk_bytes += fs_freelist_index_to_size (fl_index);
       cur = next;
     }
   while (cur != f->start_chunk);

   oldheap = ssvm_push_heap (sh);
   svm_fifo_free_chunk_lookup (f);
   ssvm_pop_heap (oldheap);

   /* not allocated on segment heap */
   svm_fifo_free_ooo_data (f);

   if (CLIB_DEBUG)
     {
       f->master_session_index = ~0;
       f->master_thread_index = ~0;
     }

   fsh->n_active_fifos--;
   ssvm_unlock_non_recursive (sh);
 }

 int
 fifo_segment_prealloc_fifo_hdrs (fifo_segment_t * fs, u32 batch_size)
 {
   fifo_segment_header_t *fsh = fs->h;
   svm_fifo_t *f;
   void *oldheap;
   u32 size;
   u8 *fmem;
   int i;

   size = (sizeof (*f)) * batch_size;

   oldheap = ssvm_push_heap (fs->ssvm.sh);
   fmem = clib_mem_alloc_aligned_at_offset (size, CLIB_CACHE_LINE_BYTES,
 					   0 /* align_offset */ ,
 					   0 /* os_out_of_memory */ );
   ssvm_pop_heap (oldheap);

   /* Out of space.. */
   if (fmem == 0)
     return -1;

   /* Carve fifo + chunk space */
   for (i = 0; i < batch_size; i++)
     {
       f = (svm_fifo_t *) fmem;
       memset (f, 0, sizeof (*f));
       f->next = fsh->free_fifos;
       fsh->free_fifos = f;
       fmem += sizeof (*f);
     }

   fsh->n_free_bytes -= size;

   return 0;
 }

 int
 fifo_segment_prealloc_fifo_chunks (fifo_segment_t * fs, u32 chunk_size,
 				   u32 batch_size)
 {
   fifo_segment_header_t *fsh = fs->h;
   u32 size, rounded_data_size, fl_index;
   svm_fifo_chunk_t *c;
   void *oldheap;
   u8 *cmem;
   int i;

   if (!fs_chunk_size_is_valid (chunk_size))
     {
       clib_warning ("chunk size out of range %d", chunk_size);
       return -1;
     }

   fl_index = fs_freelist_for_size (chunk_size);
   vec_validate_init_empty (fsh->free_chunks, fl_index, 0);
   rounded_data_size = fs_freelist_index_to_size (fl_index);
   size = (sizeof (*c) + rounded_data_size) * batch_size;

   oldheap = ssvm_push_heap (fs->ssvm.sh);
   cmem = clib_mem_alloc_aligned_at_offset (size, CLIB_CACHE_LINE_BYTES,
 					   0 /* align_offset */ ,
 					   0 /* os_out_of_memory */ );
   ssvm_pop_heap (oldheap);

   /* Out of space.. */
   if (cmem == 0)
     return -1;

   /* Carve fifo + chunk space */
   for (i = 0; i < batch_size; i++)
     {
       c = (svm_fifo_chunk_t *) cmem;
       c->start_byte = 0;
       c->length = rounded_data_size;
       c->next = fsh->free_chunks[fl_index];
       fsh->free_chunks[fl_index] = c;
       cmem += sizeof (*c) + rounded_data_size;
     }

   fsh->n_fl_chunk_bytes += batch_size * rounded_data_size;
   fsh->n_free_bytes -= size;

   return 0;
 }

 /**
  * Pre-allocates fifo pairs in fifo segment
  */
 void
 fifo_segment_preallocate_fifo_pairs (fifo_segment_t * fs,
 				     u32 rx_fifo_size, u32 tx_fifo_size,
 				     u32 * n_fifo_pairs)
 {
   u32 rx_rounded_data_size, tx_rounded_data_size, pair_size, pairs_to_alloc;
   int rx_fl_index, tx_fl_index;
   uword space_available;
   u32 hdrs;

   /* Parameter check */
   if (rx_fifo_size == 0 || tx_fifo_size == 0 || *n_fifo_pairs == 0)
     return;

   if (!fs_chunk_size_is_valid (rx_fifo_size))
     {
       clib_warning ("rx fifo_size out of range %d", rx_fifo_size);
       return;
     }

   if (!fs_chunk_size_is_valid (tx_fifo_size))
     {
       clib_warning ("tx fifo_size out of range %d", tx_fifo_size);
       return;
     }

   rx_rounded_data_size = (1 << (max_log2 (rx_fifo_size)));
   rx_fl_index = fs_freelist_for_size (rx_fifo_size);
   tx_rounded_data_size = (1 << (max_log2 (tx_fifo_size)));
   tx_fl_index = fs_freelist_for_size (tx_fifo_size);

   hdrs = sizeof (svm_fifo_t) + sizeof (svm_fifo_chunk_t);

   /* Calculate space requirements */
   pair_size = 2 * hdrs + rx_rounded_data_size + tx_rounded_data_size;
   space_available = fs_free_space (fs);
   pairs_to_alloc = clib_min (space_available / pair_size, *n_fifo_pairs);

   if (fs_try_alloc_fifo_batch (fs, rx_fl_index, pairs_to_alloc))
     clib_warning ("rx prealloc failed");
   if (fs_try_alloc_fifo_batch (fs, tx_fl_index, pairs_to_alloc))
     clib_warning ("tx prealloc failed");

   /* Account for the pairs allocated */
   *n_fifo_pairs -= pairs_to_alloc;
 }

 int
 fifo_segment_grow_fifo (fifo_segment_t * fs, svm_fifo_t * f, u32 chunk_size)
 {
   ssvm_shared_header_t *sh;
   svm_fifo_chunk_t *c;
   void *oldheap;
   int fl_index;

   if (!fs_chunk_size_is_valid (chunk_size))
     {
       clib_warning ("chunk size out of range %d", chunk_size);
       return 0;
     }

   fl_index = fs_freelist_for_size (chunk_size);

   sh = fs->ssvm.sh;
   ssvm_lock_non_recursive (sh, 1);

   vec_validate_init_empty (fs->h->free_chunks, fl_index, 0);
   c = fs->h->free_chunks[fl_index];

   oldheap = ssvm_push_heap (sh);

   if (!c)
     {
       c = svm_fifo_chunk_alloc (chunk_size);
       if (!c)
 	{
 	  ssvm_pop_heap (oldheap);
 	  return -1;
 	}
     }
   else
     {
       fs->h->free_chunks[fl_index] = c->next;
       c->next = 0;
     }

   svm_fifo_add_chunk (f, c);

   ssvm_pop_heap (oldheap);
   ssvm_unlock_non_recursive (sh);
   return 0;
 }

 int
 fifo_segment_collect_fifo_chunks (fifo_segment_t * fs, svm_fifo_t * f)
 {
   svm_fifo_chunk_t *cur, *next;
   ssvm_shared_header_t *sh;
   void *oldheap;
   int fl_index;

   sh = fs->ssvm.sh;
   ssvm_lock_non_recursive (sh, 1);

   oldheap = ssvm_push_heap (sh);
   cur = svm_fifo_collect_chunks (f);

   while (cur)
     {
       next = cur->next;
       fl_index = fs_freelist_for_size (cur->length);
       cur->next = fs->h->free_chunks[fl_index];
       fs->h->free_chunks[fl_index] = cur;
       cur = next;
     }

   ssvm_pop_heap (oldheap);
   ssvm_unlock_non_recursive (sh);

   return 0;
 }

 /**
  * Get number of active fifos
  */
 u32
 fifo_segment_num_fifos (fifo_segment_t * fs)
 {
   return fs->h->n_active_fifos;
 }

 u32
 fifo_segment_num_free_fifos (fifo_segment_t * fs)
 {
   fifo_segment_header_t *fsh = fs->h;
   svm_fifo_t *f;
   u32 count = 0;

   f = fsh->free_fifos;
   if (f == 0)
     return 0;

   while (f)
     {
       f = f->next;
       count++;
     }
   return count;
 }

 u32
 fifo_segment_num_free_chunks (fifo_segment_t * fs, u32 size)
 {
   u32 count = 0, rounded_size, fl_index;
   fifo_segment_header_t *fsh;
   svm_fifo_chunk_t *c;
   int i;

   fsh = fs->h;

   /* Count all free chunks? */
   if (size == ~0)
     {
       for (i = 0; i < vec_len (fsh->free_chunks); i++)
 	{
 	  c = fsh->free_chunks[i];
 	  if (c == 0)
 	    continue;

 	  while (c)
 	    {
 	      c = c->next;
 	      count++;
 	    }
 	}
       return count;
     }

   rounded_size = (1 << (max_log2 (size)));
   fl_index = fs_freelist_for_size (rounded_size);

   if (fl_index >= vec_len (fsh->free_chunks))
     return 0;

   c = fsh->free_chunks[fl_index];
   if (c == 0)
     return 0;

   while (c)
     {
       c = c->next;
       count++;
     }
   return count;
 }

 void
 fifo_segment_update_free_bytes (fifo_segment_t * fs)
 {
   fs->h->n_free_bytes = fs_free_space (fs);
 }

 u32
 fifo_segment_free_bytes (fifo_segment_t * fs)
 {
   return fs->h->n_free_bytes;
 }

 u32
 fifo_segment_chunk_prealloc_bytes (fifo_segment_t * fs)
 {
   return fs->h->n_fl_chunk_bytes;
 }

 u8
 fifo_segment_has_fifos (fifo_segment_t * fs)
 {
   return fs->h->fifos != 0;
 }

 svm_fifo_t *
 fifo_segment_get_fifo_list (fifo_segment_t * fs)
 {
   return fs->h->fifos;
 }

 u8 *
 format_fifo_segment_type (u8 * s, va_list * args)
 {
   fifo_segment_t *sp;
   sp = va_arg (*args, fifo_segment_t *);
   ssvm_segment_type_t st = ssvm_type (&sp->ssvm);

   if (st == SSVM_SEGMENT_PRIVATE)
     s = format (s, "%s", "private-heap");
   else if (st == SSVM_SEGMENT_MEMFD)
     s = format (s, "%s", "memfd");
   else if (st == SSVM_SEGMENT_SHM)
     s = format (s, "%s", "shm");
   else
     s = format (s, "%s", "unknown");
   return s;
 }

 /**
  * Segment format function
  */
 u8 *
 format_fifo_segment (u8 * s, va_list * args)
 {
   fifo_segment_t *sp = va_arg (*args, fifo_segment_t *);
   int verbose __attribute__ ((unused)) = va_arg (*args, int);
   fifo_segment_header_t *fsh = sp->h;
   u32 count, indent;
   svm_fifo_chunk_t *c;
   int i;

   indent = format_get_indent (s) + 2;
 #if USE_DLMALLOC == 0
   s = format (s, "%U segment heap: %U\n", format_white_space, indent,
 	      format_mheap, svm_fifo_segment_heap (sp), verbose);
   s = format (s, "%U segment has %u active fifos\n",
 	      format_white_space, indent, fifo_segment_num_fifos (sp));
 #endif

   for (i = 0; i < vec_len (fsh->free_chunks); i++)
     {
       c = fsh->free_chunks[i];
       if (c == 0)
 	continue;
       count = 0;
       while (c)
 	{
 	  c = c->next;
 	  count++;
 	}

       s = format (s, "%U%-5u Kb: %u free",
 		  format_white_space, indent + 2,
 		  1 << (i + max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE) - 10),
 		  count);
     }
   return s;
 }

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	* Copyright (c) 2016-2019 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.
	*/

	#include <svm/fifo_segment.h>

	/**
	* Fifo segment free space
	*
	* Queries the underlying memory manager, dlmalloc, for free space. Since this
	* ends up walking the internal data structures, it should not be called
	* indiscriminately.
	*
	* @param fs fifo segment
	* @return number of free bytes
	*/
	static u32
	fs_free_space (fifo_segment_t * fs)
	{
	struct dlmallinfo dlminfo;

	dlminfo = mspace_mallinfo (fs->ssvm.sh->heap);
	return dlminfo.fordblks;
	}

	/**
	* Initialize fifo segment shared header
	*/
	int
	fifo_segment_init (fifo_segment_t * fs)
	{
	fifo_segment_header_t *fsh;
	ssvm_shared_header_t *sh;
	void *oldheap;

	sh = fs->ssvm.sh;
	oldheap = ssvm_push_heap (sh);

	fsh = clib_mem_alloc (sizeof (*fsh));
	clib_memset (fsh, 0, sizeof (*fsh));
	fs->h = sh->opaque[0] = fsh;

	ssvm_pop_heap (oldheap);

	fsh->n_free_bytes = fs_free_space (fs);
	sh->ready = 1;
	return (0);
	}

	/**
	* Create a fifo segment and initialize as master
	*/
	int
	fifo_segment_create (fifo_segment_main_t * sm, fifo_segment_create_args_t * a)
	{
	fifo_segment_t *fs;
	uword baseva;
	int rv;

	/* Allocate a fresh segment */
	pool_get_zero (sm->segments, fs);

	baseva = a->segment_type == SSVM_SEGMENT_PRIVATE ? ~0ULL : sm->next_baseva;
	fs->ssvm.ssvm_size = a->segment_size;
	fs->ssvm.i_am_master = 1;
	fs->ssvm.my_pid = getpid ();
	fs->ssvm.name = format (0, "%s%c", a->segment_name, 0);
	fs->ssvm.requested_va = baseva;

	if ((rv = ssvm_master_init (&fs->ssvm, a->segment_type)))
	{
	pool_put (sm->segments, fs);
	return (rv);
	}

	/* Note: requested_va updated due to seg base addr randomization */
	sm->next_baseva = fs->ssvm.sh->ssvm_va + fs->ssvm.ssvm_size;

	fifo_segment_init (fs);
	vec_add1 (a->new_segment_indices, fs - sm->segments);
	return (0);
	}

	/**
	* Attach as slave to a fifo segment
	*/
	int
	fifo_segment_attach (fifo_segment_main_t * sm, fifo_segment_create_args_t * a)
	{
	fifo_segment_t *s;
	int rv;

	pool_get_zero (sm->segments, s);

	s->ssvm.ssvm_size = a->segment_size;
	s->ssvm.my_pid = getpid ();
	s->ssvm.name = format (0, "%s%c", a->segment_name, 0);
	s->ssvm.requested_va = sm->next_baseva;
	if (a->segment_type == SSVM_SEGMENT_MEMFD)
	s->ssvm.fd = a->memfd_fd;
	else
	s->ssvm.attach_timeout = sm->timeout_in_seconds;

	if ((rv = ssvm_slave_init (&s->ssvm, a->segment_type)))
	{
	_vec_len (s) = vec_len (s) - 1;
	return (rv);
	}

	/* Fish the segment header */
	s->h = s->ssvm.sh->opaque[0];

	vec_add1 (a->new_segment_indices, s - sm->segments);
	return (0);
	}

	void
	fifo_segment_delete (fifo_segment_main_t * sm, fifo_segment_t * s)
	{
	ssvm_delete (&s->ssvm);
	clib_memset (s, 0xfe, sizeof (*s));
	pool_put (sm->segments, s);
	}

	u32
	fifo_segment_index (fifo_segment_main_t * sm, fifo_segment_t * s)
	{
	return s - sm->segments;
	}

	void *
	svm_fifo_segment_heap (fifo_segment_t * seg)
	{
	return seg->ssvm.sh->heap;
	}

	fifo_segment_t *
	fifo_segment_get_segment (fifo_segment_main_t * sm, u32 segment_index)
	{
	return pool_elt_at_index (sm->segments, segment_index);
	}

	void
	fifo_segment_info (fifo_segment_t * seg, char *address, size_t size)
	{
	address = (char ) seg->ssvm.sh->ssvm_va;
	*size = seg->ssvm.ssvm_size;
	}

	void
	fifo_segment_main_init (fifo_segment_main_t * sm, u64 baseva,
	u32 timeout_in_seconds)
	{
	sm->next_baseva = baseva;
	sm->timeout_in_seconds = timeout_in_seconds;
	}

	static inline u32
	fs_freelist_for_size (u32 size)
	{
	return max_log2 (size) - max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE);
	}

	static inline u32
	fs_freelist_index_to_size (u32 fl_index)
	{
	return 1 << (fl_index + max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE));
	}

	static inline int
	fs_chunk_size_is_valid (u32 size)
	{
	/*
	* 4K minimum. It's not likely that anything good will happen
	* with a smaller FIFO.
	*/
	return size >= FIFO_SEGMENT_MIN_FIFO_SIZE
	&& size <= FIFO_SEGMENT_MAX_FIFO_SIZE;
	}

	static svm_fifo_t *
	fs_try_alloc_fifo_freelist (fifo_segment_t * fs, u32 fl_index, u32 data_bytes)
	{
	fifo_segment_header_t *fsh = fs->h;
	svm_fifo_chunk_t *c;
	svm_fifo_t *f;

	f = fsh->free_fifos;
	c = fsh->free_chunks[fl_index];

	if (!f \|\| !c)
	return 0;

	fsh->free_fifos = f->next;
	fsh->free_chunks[fl_index] = c->next;
	c->next = c;
	c->start_byte = 0;
	c->length = data_bytes;
	memset (f, 0, sizeof (*f));
	f->start_chunk = c;
	f->end_chunk = c;

	fsh->n_fl_chunk_bytes -= fs_freelist_index_to_size (fl_index);
	return f;
	}

	static svm_fifo_t *
	fs_try_alloc_fifo_freelist_multi_chunk (fifo_segment_t * fs, u32 data_bytes)
	{
	svm_fifo_chunk_t c, first = 0, *last = 0;
	fifo_segment_header_t *fsh = fs->h;
	u32 fl_index, fl_size, n_alloc = 0;
	svm_fifo_t *f;

	f = fsh->free_fifos;
	if (!f)
	{
	void *oldheap = ssvm_push_heap (fs->ssvm.sh);
	f = clib_mem_alloc_aligned (sizeof (*f), CLIB_CACHE_LINE_BYTES);
	ssvm_pop_heap (oldheap);
	if (!f)
	return 0;
	memset (f, 0, sizeof (*f));
	}

	fl_index = fs_freelist_for_size (data_bytes) - 1;
	vec_validate_init_empty (fsh->free_chunks, fl_index, 0);
	fl_size = fs_freelist_index_to_size (fl_index);

	while (data_bytes)
	{
	c = fsh->free_chunks[fl_index];
	if (c)
	{
	fsh->free_chunks[fl_index] = c->next;
	if (!last)
	last = c;
	c->next = first;
	first = c;
	n_alloc += c->length;
	c->length = clib_min (fl_size, data_bytes);
	data_bytes -= c->length;
	}
	else
	{
	ASSERT (fl_index > 0);
	fl_index -= 1;
	fl_size = fl_size >> 1;
	}
	}
	f->start_chunk = first;
	f->end_chunk = last;
	last->next = first;
	fsh->n_fl_chunk_bytes -= n_alloc;
	return f;
	}

	static int
	fs_try_alloc_fifo_batch (fifo_segment_t * fs, u32 fl_index, u32 batch_size)
	{
	fifo_segment_header_t *fsh = fs->h;
	u32 size, hdrs, rounded_data_size;
	svm_fifo_chunk_t *c;
	svm_fifo_t *f;
	void *oldheap;
	u8 *fmem;
	int i;

	vec_validate_init_empty (fsh->free_chunks, fl_index, 0);
	rounded_data_size = fs_freelist_index_to_size (fl_index);
	hdrs = sizeof (f) + sizeof (c);
	size = (hdrs + rounded_data_size) * batch_size;

	oldheap = ssvm_push_heap (fs->ssvm.sh);
	fmem = clib_mem_alloc_aligned_at_offset (size, CLIB_CACHE_LINE_BYTES,
	0 /* align_offset */ ,
	0 /* os_out_of_memory */ );
	ssvm_pop_heap (oldheap);

	/* Out of space.. */
	if (fmem == 0)
	return -1;

	/* Carve fifo + chunk space */
	for (i = 0; i < batch_size; i++)
	{
	f = (svm_fifo_t *) fmem;
	memset (f, 0, sizeof (*f));
	f->next = fsh->free_fifos;
	fsh->free_fifos = f;
	c = (svm_fifo_chunk_t ) (fmem + sizeof (f));
	c->start_byte = 0;
	c->length = rounded_data_size;
	c->next = fsh->free_chunks[fl_index];
	fsh->free_chunks[fl_index] = c;
	fmem += hdrs + rounded_data_size;
	}

	fsh->n_fl_chunk_bytes += batch_size * rounded_data_size;
	fsh->n_free_bytes -= size;

	return 0;
	}

	/**
	* Try to allocate new fifo
	*
	* Tries the following steps in order:
	* - grab fifo and chunk from freelists
	* - batch fifo and chunk allocation
	* - single fifo allocation
	* - grab multiple fifo chunks from freelists
	*/
	static svm_fifo_t *
	fs_try_alloc_fifo (fifo_segment_t * fs, u32 data_bytes)
	{
	fifo_segment_header_t *fsh = fs->h;
	u32 fifo_sz, fl_index;
	svm_fifo_t *f = 0;

	fl_index = fs_freelist_for_size (data_bytes);
	vec_validate_init_empty (fsh->free_chunks, fl_index, 0);
	fifo_sz = sizeof (svm_fifo_t) + sizeof (svm_fifo_chunk_t);
	fifo_sz += 1 << max_log2 (data_bytes);

	if (fsh->free_fifos && fsh->free_chunks[fl_index])
	{
	f = fs_try_alloc_fifo_freelist (fs, fl_index, data_bytes);
	if (f)
	goto done;
	}
	if (fifo_sz * FIFO_SEGMENT_ALLOC_BATCH_SIZE < fsh->n_free_bytes)
	{
	if (fs_try_alloc_fifo_batch (fs, fl_index,
	FIFO_SEGMENT_ALLOC_BATCH_SIZE))
	goto done;

	f = fs_try_alloc_fifo_freelist (fs, fl_index, data_bytes);
	goto done;
	}
	if (fifo_sz <= fsh->n_free_bytes)
	{
	void *oldheap = ssvm_push_heap (fs->ssvm.sh);
	f = svm_fifo_create (data_bytes);
	ssvm_pop_heap (oldheap);
	if (f)
	{
	fsh->n_free_bytes -= fifo_sz;
	goto done;
	}
	}
	if (data_bytes <= fsh->n_fl_chunk_bytes)
	f = fs_try_alloc_fifo_freelist_multi_chunk (fs, data_bytes);

	done:

	return f;
	}

	/**
	* Allocate fifo in fifo segment
	*/
	svm_fifo_t *
	fifo_segment_alloc_fifo (fifo_segment_t * fs, u32 data_bytes,
	fifo_segment_ftype_t ftype)
	{
	fifo_segment_header_t *fsh;
	svm_fifo_t *f = 0;

	if (!fs_chunk_size_is_valid (data_bytes))
	{
	clib_warning ("fifo size out of range %d", data_bytes);
	return 0;
	}

	fsh = fs->h;
	ssvm_lock_non_recursive (fs->ssvm.sh, 1);

	f = fs_try_alloc_fifo (fs, data_bytes);
	if (!f)
	goto done;

	/* (re)initialize the fifo, as in svm_fifo_create */
	svm_fifo_init (f, data_bytes);

	/* If rx fifo type add to active fifos list. When cleaning up segment,
	* we need a list of active sessions that should be disconnected. Since
	* both rx and tx fifos keep pointers to the session, it's enough to track
	* only one. */
	if (ftype == FIFO_SEGMENT_RX_FIFO)
	{
	if (fsh->fifos)
	{
	fsh->fifos->prev = f;
	f->next = fsh->fifos;
	}
	fsh->fifos = f;
	f->flags \|= SVM_FIFO_F_LL_TRACKED;
	}
	fsh->n_active_fifos++;

	done:
	ssvm_unlock_non_recursive (fs->ssvm.sh);
	return (f);
	}

	/**
	* Free fifo allocated in fifo segment
	*/
	void
	fifo_segment_free_fifo (fifo_segment_t * fs, svm_fifo_t * f)
	{
	svm_fifo_chunk_t cur, next;
	fifo_segment_header_t *fsh;
	ssvm_shared_header_t *sh;
	void *oldheap;
	int fl_index;

	ASSERT (f->refcnt > 0);

	if (--f->refcnt > 0)
	return;

	sh = fs->ssvm.sh;
	fsh = fs->h;

	ssvm_lock_non_recursive (sh, 2);

	/* Remove from active list. Only rx fifos are tracked */
	if (f->flags & SVM_FIFO_F_LL_TRACKED)
	{
	if (f->prev)
	f->prev->next = f->next;
	else
	fsh->fifos = f->next;
	if (f->next)
	f->next->prev = f->prev;
	f->flags &= ~SVM_FIFO_F_LL_TRACKED;
	}

	/* Add to free list */
	f->next = fsh->free_fifos;
	f->prev = 0;
	fsh->free_fifos = f;

	/* Free fifo chunks */
	cur = f->start_chunk;
	do
	{
	next = cur->next;
	fl_index = fs_freelist_for_size (cur->length);
	ASSERT (fl_index < vec_len (fsh->free_chunks));
	cur->next = fsh->free_chunks[fl_index];
	fsh->free_chunks[fl_index] = cur;
	fsh->n_fl_chunk_bytes += fs_freelist_index_to_size (fl_index);
	cur = next;
	}
	while (cur != f->start_chunk);

	oldheap = ssvm_push_heap (sh);
	svm_fifo_free_chunk_lookup (f);
	ssvm_pop_heap (oldheap);

	/* not allocated on segment heap */
	svm_fifo_free_ooo_data (f);

	if (CLIB_DEBUG)
	{
	f->master_session_index = ~0;
	f->master_thread_index = ~0;
	}

	fsh->n_active_fifos--;
	ssvm_unlock_non_recursive (sh);
	}

	int
	fifo_segment_prealloc_fifo_hdrs (fifo_segment_t * fs, u32 batch_size)
	{
	fifo_segment_header_t *fsh = fs->h;
	svm_fifo_t *f;
	void *oldheap;
	u32 size;
	u8 *fmem;
	int i;

	size = (sizeof (f)) batch_size;

	oldheap = ssvm_push_heap (fs->ssvm.sh);
	fmem = clib_mem_alloc_aligned_at_offset (size, CLIB_CACHE_LINE_BYTES,
	0 /* align_offset */ ,
	0 /* os_out_of_memory */ );
	ssvm_pop_heap (oldheap);

	/* Out of space.. */
	if (fmem == 0)
	return -1;

	/* Carve fifo + chunk space */
	for (i = 0; i < batch_size; i++)
	{
	f = (svm_fifo_t *) fmem;
	memset (f, 0, sizeof (*f));
	f->next = fsh->free_fifos;
	fsh->free_fifos = f;
	fmem += sizeof (*f);
	}

	fsh->n_free_bytes -= size;

	return 0;
	}

	int
	fifo_segment_prealloc_fifo_chunks (fifo_segment_t * fs, u32 chunk_size,
	u32 batch_size)
	{
	fifo_segment_header_t *fsh = fs->h;
	u32 size, rounded_data_size, fl_index;
	svm_fifo_chunk_t *c;
	void *oldheap;
	u8 *cmem;
	int i;

	if (!fs_chunk_size_is_valid (chunk_size))
	{
	clib_warning ("chunk size out of range %d", chunk_size);
	return -1;
	}

	fl_index = fs_freelist_for_size (chunk_size);
	vec_validate_init_empty (fsh->free_chunks, fl_index, 0);
	rounded_data_size = fs_freelist_index_to_size (fl_index);
	size = (sizeof (c) + rounded_data_size) batch_size;

	oldheap = ssvm_push_heap (fs->ssvm.sh);
	cmem = clib_mem_alloc_aligned_at_offset (size, CLIB_CACHE_LINE_BYTES,
	0 /* align_offset */ ,
	0 /* os_out_of_memory */ );
	ssvm_pop_heap (oldheap);

	/* Out of space.. */
	if (cmem == 0)
	return -1;

	/* Carve fifo + chunk space */
	for (i = 0; i < batch_size; i++)
	{
	c = (svm_fifo_chunk_t *) cmem;
	c->start_byte = 0;
	c->length = rounded_data_size;
	c->next = fsh->free_chunks[fl_index];
	fsh->free_chunks[fl_index] = c;
	cmem += sizeof (*c) + rounded_data_size;
	}

	fsh->n_fl_chunk_bytes += batch_size * rounded_data_size;
	fsh->n_free_bytes -= size;

	return 0;
	}

	/**
	* Pre-allocates fifo pairs in fifo segment
	*/
	void
	fifo_segment_preallocate_fifo_pairs (fifo_segment_t * fs,
	u32 rx_fifo_size, u32 tx_fifo_size,
	u32 * n_fifo_pairs)
	{
	u32 rx_rounded_data_size, tx_rounded_data_size, pair_size, pairs_to_alloc;
	int rx_fl_index, tx_fl_index;
	uword space_available;
	u32 hdrs;

	/* Parameter check */
	if (rx_fifo_size == 0 \|\| tx_fifo_size == 0 \|\| *n_fifo_pairs == 0)
	return;

	if (!fs_chunk_size_is_valid (rx_fifo_size))
	{
	clib_warning ("rx fifo_size out of range %d", rx_fifo_size);
	return;
	}

	if (!fs_chunk_size_is_valid (tx_fifo_size))
	{
	clib_warning ("tx fifo_size out of range %d", tx_fifo_size);
	return;
	}

	rx_rounded_data_size = (1 << (max_log2 (rx_fifo_size)));
	rx_fl_index = fs_freelist_for_size (rx_fifo_size);
	tx_rounded_data_size = (1 << (max_log2 (tx_fifo_size)));
	tx_fl_index = fs_freelist_for_size (tx_fifo_size);

	hdrs = sizeof (svm_fifo_t) + sizeof (svm_fifo_chunk_t);

	/* Calculate space requirements */
	pair_size = 2 * hdrs + rx_rounded_data_size + tx_rounded_data_size;
	space_available = fs_free_space (fs);
	pairs_to_alloc = clib_min (space_available / pair_size, *n_fifo_pairs);

	if (fs_try_alloc_fifo_batch (fs, rx_fl_index, pairs_to_alloc))
	clib_warning ("rx prealloc failed");
	if (fs_try_alloc_fifo_batch (fs, tx_fl_index, pairs_to_alloc))
	clib_warning ("tx prealloc failed");

	/* Account for the pairs allocated */
	*n_fifo_pairs -= pairs_to_alloc;
	}

	int
	fifo_segment_grow_fifo (fifo_segment_t * fs, svm_fifo_t * f, u32 chunk_size)
	{
	ssvm_shared_header_t *sh;
	svm_fifo_chunk_t *c;
	void *oldheap;
	int fl_index;

	if (!fs_chunk_size_is_valid (chunk_size))
	{
	clib_warning ("chunk size out of range %d", chunk_size);
	return 0;
	}

	fl_index = fs_freelist_for_size (chunk_size);

	sh = fs->ssvm.sh;
	ssvm_lock_non_recursive (sh, 1);

	vec_validate_init_empty (fs->h->free_chunks, fl_index, 0);
	c = fs->h->free_chunks[fl_index];

	oldheap = ssvm_push_heap (sh);

	if (!c)
	{
	c = svm_fifo_chunk_alloc (chunk_size);
	if (!c)
	{
	ssvm_pop_heap (oldheap);
	return -1;
	}
	}
	else
	{
	fs->h->free_chunks[fl_index] = c->next;
	c->next = 0;
	}

	svm_fifo_add_chunk (f, c);

	ssvm_pop_heap (oldheap);
	ssvm_unlock_non_recursive (sh);
	return 0;
	}

	int
	fifo_segment_collect_fifo_chunks (fifo_segment_t * fs, svm_fifo_t * f)
	{
	svm_fifo_chunk_t cur, next;
	ssvm_shared_header_t *sh;
	void *oldheap;
	int fl_index;

	sh = fs->ssvm.sh;
	ssvm_lock_non_recursive (sh, 1);

	oldheap = ssvm_push_heap (sh);
	cur = svm_fifo_collect_chunks (f);

	while (cur)
	{
	next = cur->next;
	fl_index = fs_freelist_for_size (cur->length);
	cur->next = fs->h->free_chunks[fl_index];
	fs->h->free_chunks[fl_index] = cur;
	cur = next;
	}

	ssvm_pop_heap (oldheap);
	ssvm_unlock_non_recursive (sh);

	return 0;
	}

	/**
	* Get number of active fifos
	*/
	u32
	fifo_segment_num_fifos (fifo_segment_t * fs)
	{
	return fs->h->n_active_fifos;
	}

	u32
	fifo_segment_num_free_fifos (fifo_segment_t * fs)
	{
	fifo_segment_header_t *fsh = fs->h;
	svm_fifo_t *f;
	u32 count = 0;

	f = fsh->free_fifos;
	if (f == 0)
	return 0;

	while (f)
	{
	f = f->next;
	count++;
	}
	return count;
	}

	u32
	fifo_segment_num_free_chunks (fifo_segment_t * fs, u32 size)
	{
	u32 count = 0, rounded_size, fl_index;
	fifo_segment_header_t *fsh;
	svm_fifo_chunk_t *c;
	int i;

	fsh = fs->h;

	/* Count all free chunks? */
	if (size == ~0)
	{
	for (i = 0; i < vec_len (fsh->free_chunks); i++)
	{
	c = fsh->free_chunks[i];
	if (c == 0)
	continue;

	while (c)
	{
	c = c->next;
	count++;
	}
	}
	return count;
	}

	rounded_size = (1 << (max_log2 (size)));
	fl_index = fs_freelist_for_size (rounded_size);

	if (fl_index >= vec_len (fsh->free_chunks))
	return 0;

	c = fsh->free_chunks[fl_index];
	if (c == 0)
	return 0;

	while (c)
	{
	c = c->next;
	count++;
	}
	return count;
	}

	void
	fifo_segment_update_free_bytes (fifo_segment_t * fs)
	{
	fs->h->n_free_bytes = fs_free_space (fs);
	}

	u32
	fifo_segment_free_bytes (fifo_segment_t * fs)
	{
	return fs->h->n_free_bytes;
	}

	u32
	fifo_segment_chunk_prealloc_bytes (fifo_segment_t * fs)
	{
	return fs->h->n_fl_chunk_bytes;
	}

	u8
	fifo_segment_has_fifos (fifo_segment_t * fs)
	{
	return fs->h->fifos != 0;
	}

	svm_fifo_t *
	fifo_segment_get_fifo_list (fifo_segment_t * fs)
	{
	return fs->h->fifos;
	}

	u8 *
	format_fifo_segment_type (u8 * s, va_list * args)
	{
	fifo_segment_t *sp;
	sp = va_arg (args, fifo_segment_t );
	ssvm_segment_type_t st = ssvm_type (&sp->ssvm);

	if (st == SSVM_SEGMENT_PRIVATE)
	s = format (s, "%s", "private-heap");
	else if (st == SSVM_SEGMENT_MEMFD)
	s = format (s, "%s", "memfd");
	else if (st == SSVM_SEGMENT_SHM)
	s = format (s, "%s", "shm");
	else
	s = format (s, "%s", "unknown");
	return s;
	}

	/**
	* Segment format function
	*/
	u8 *
	format_fifo_segment (u8 * s, va_list * args)
	{
	fifo_segment_t sp = va_arg (args, fifo_segment_t *);
	int verbose __attribute__ ((unused)) = va_arg (*args, int);
	fifo_segment_header_t *fsh = sp->h;
	u32 count, indent;
	svm_fifo_chunk_t *c;
	int i;

	indent = format_get_indent (s) + 2;
	#if USE_DLMALLOC == 0
	s = format (s, "%U segment heap: %U\n", format_white_space, indent,
	format_mheap, svm_fifo_segment_heap (sp), verbose);
	s = format (s, "%U segment has %u active fifos\n",
	format_white_space, indent, fifo_segment_num_fifos (sp));
	#endif

	for (i = 0; i < vec_len (fsh->free_chunks); i++)
	{
	c = fsh->free_chunks[i];
	if (c == 0)
	continue;
	count = 0;
	while (c)
	{
	c = c->next;
	count++;
	}

	s = format (s, "%U%-5u Kb: %u free",
	format_white_space, indent + 2,
	1 << (i + max_log2 (FIFO_SEGMENT_MIN_FIFO_SIZE) - 10),
	count);
	}
	return s;
	}

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