libeio/etp.c

/*
 * libetp implementation
 *
 * Copyright (c) 2007,2008,2009,2010,2011,2012,2013,2015 Marc Alexander Lehmann <libetp@schmorp.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 *
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#ifndef ETP_API_DECL
# define ETP_API_DECL static
#endif

#ifndef ETP_PRI_MIN
# define ETP_PRI_MIN 0
# define ETP_PRI_MAX 0
#endif

#ifndef ETP_TYPE_QUIT
# define ETP_TYPE_QUIT 0
#endif

#ifndef ETP_TYPE_GROUP
# define ETP_TYPE_GROUP 1
#endif

#ifndef ETP_WANT_POLL
# define ETP_WANT_POLL(pool) pool->want_poll_cb (pool->userdata)
#endif
#ifndef ETP_DONE_POLL
# define ETP_DONE_POLL(pool) pool->done_poll_cb (pool->userdata)
#endif

#define ETP_NUM_PRI (ETP_PRI_MAX - ETP_PRI_MIN + 1)

#define ETP_TICKS ((1000000 + 1023) >> 10)

enum {
  ETP_FLAG_GROUPADD = 0x04, /* some request was added to the group */
  ETP_FLAG_DELAYED  = 0x08, /* groiup request has been delayed */
};

/* calculate time difference in ~1/ETP_TICKS of a second */
ecb_inline int
etp_tvdiff (struct timeval *tv1, struct timeval *tv2)
{
  return  (tv2->tv_sec  - tv1->tv_sec ) * ETP_TICKS
       + ((tv2->tv_usec - tv1->tv_usec) >> 10);
}

struct etp_tmpbuf
{
  void *ptr;
  int len;
};

static void *
etp_tmpbuf_get (struct etp_tmpbuf *buf, int len)
{
  if (buf->len < len)
    {
      free (buf->ptr);
      buf->ptr = malloc (buf->len = len);
    }

  return buf->ptr;
}

/*
 * a somewhat faster data structure might be nice, but
 * with 8 priorities this actually needs <20 insns
 * per shift, the most expensive operation.
 */
typedef struct
{
  ETP_REQ *qs[ETP_NUM_PRI], *qe[ETP_NUM_PRI]; /* qstart, qend */
  int size;
} etp_reqq;

typedef struct etp_pool *etp_pool;

typedef struct etp_worker
{
  etp_pool pool;

  struct etp_tmpbuf tmpbuf;

  /* locked by pool->wrklock */
  struct etp_worker *prev, *next;

  xthread_t tid;

#ifdef ETP_WORKER_COMMON
  ETP_WORKER_COMMON
#endif
} etp_worker;

struct etp_pool
{
   void *userdata;

   etp_reqq req_queue;
   etp_reqq res_queue;

   unsigned int started, idle, wanted;

   unsigned int max_poll_time;     /* pool->reslock */
   unsigned int max_poll_reqs;     /* pool->reslock */

   unsigned int nreqs;    /* pool->reqlock */
   unsigned int nready;   /* pool->reqlock */
   unsigned int npending; /* pool->reqlock */
   unsigned int max_idle;      /* maximum number of threads that can pool->idle indefinitely */
   unsigned int idle_timeout; /* number of seconds after which an pool->idle threads exit */

   void (*want_poll_cb) (void *userdata);
   void (*done_poll_cb) (void *userdata);
 
   xmutex_t wrklock;
   xmutex_t reslock;
   xmutex_t reqlock;
   xcond_t  reqwait;

   etp_worker wrk_first;
};

#define ETP_WORKER_LOCK(wrk)   X_LOCK   (pool->wrklock)
#define ETP_WORKER_UNLOCK(wrk) X_UNLOCK (pool->wrklock)

/* worker threads management */

static void
etp_worker_clear (etp_worker *wrk)
{
}

static void ecb_cold
etp_worker_free (etp_worker *wrk)
{
  free (wrk->tmpbuf.ptr);

  wrk->next->prev = wrk->prev;
  wrk->prev->next = wrk->next;

  free (wrk);
}

ETP_API_DECL unsigned int
etp_nreqs (etp_pool pool)
{
  int retval;
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  retval = pool->nreqs;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
  return retval;
}

ETP_API_DECL unsigned int
etp_nready (etp_pool pool)
{
  unsigned int retval;

  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  retval = pool->nready;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);

  return retval;
}

ETP_API_DECL unsigned int
etp_npending (etp_pool pool)
{
  unsigned int retval;

  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  retval = pool->npending;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);

  return retval;
}

ETP_API_DECL unsigned int
etp_nthreads (etp_pool pool)
{
  unsigned int retval;

  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  retval = pool->started;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);

  return retval;
}

static void ecb_noinline ecb_cold
reqq_init (etp_reqq *q)
{
  int pri;

  for (pri = 0; pri < ETP_NUM_PRI; ++pri)
    q->qs[pri] = q->qe[pri] = 0;

  q->size = 0;
}

static int ecb_noinline
reqq_push (etp_reqq *q, ETP_REQ *req)
{
  int pri = req->pri;
  req->next = 0;

  if (q->qe[pri])
    {
      q->qe[pri]->next = req;
      q->qe[pri] = req;
    }
  else
    q->qe[pri] = q->qs[pri] = req;

  return q->size++;
}

static ETP_REQ * ecb_noinline
reqq_shift (etp_reqq *q)
{
  int pri;

  if (!q->size)
    return 0;

  --q->size;

  for (pri = ETP_NUM_PRI; pri--; )
    {
      ETP_REQ *req = q->qs[pri];

      if (req)
        {
          if (!(q->qs[pri] = (ETP_REQ *)req->next))
            q->qe[pri] = 0;

          return req;
        }
    }

  abort ();
}

ETP_API_DECL int ecb_cold
etp_init (etp_pool pool, void *userdata, void (*want_poll)(void *userdata), void (*done_poll)(void *userdata))
{
  X_MUTEX_CREATE (pool->wrklock);
  X_MUTEX_CREATE (pool->reslock);
  X_MUTEX_CREATE (pool->reqlock);
  X_COND_CREATE  (pool->reqwait);

  reqq_init (&pool->req_queue);
  reqq_init (&pool->res_queue);

  pool->wrk_first.next =
  pool->wrk_first.prev = &pool->wrk_first;

  pool->started  = 0;
  pool->idle     = 0;
  pool->nreqs    = 0;
  pool->nready   = 0;
  pool->npending = 0;
  pool->wanted   = 4;

  pool->max_idle = 4;      /* maximum number of threads that can pool->idle indefinitely */
  pool->idle_timeout = 10; /* number of seconds after which an pool->idle threads exit */

  pool->userdata     = userdata;
  pool->want_poll_cb = want_poll;
  pool->done_poll_cb = done_poll;

  return 0;
}

static void ecb_noinline ecb_cold
etp_proc_init (void)
{
#if HAVE_PRCTL_SET_NAME
  /* provide a more sensible "thread name" */
  char name[16 + 1];
  const int namelen = sizeof (name) - 1;
  int len;

  prctl (PR_GET_NAME, (unsigned long)name, 0, 0, 0);
  name [namelen] = 0;
  len = strlen (name);
  strcpy (name + (len <= namelen - 4 ? len : namelen - 4), "/eio");
  prctl (PR_SET_NAME, (unsigned long)name, 0, 0, 0);
#endif
}

X_THREAD_PROC (etp_proc)
{
  ETP_REQ *req;
  struct timespec ts;
  etp_worker *self = (etp_worker *)thr_arg;
  etp_pool pool = self->pool;

  etp_proc_init ();

  /* try to distribute timeouts somewhat evenly */
  ts.tv_nsec = ((unsigned long)self & 1023UL) * (1000000000UL / 1024UL);

  for (;;)
    {
      ts.tv_sec = 0;

      X_LOCK (pool->reqlock);

      for (;;)
        {
          req = reqq_shift (&pool->req_queue);

          if (ecb_expect_true (req))
            break;

          if (ts.tv_sec == 1) /* no request, but timeout detected, let's quit */
            {
              X_UNLOCK (pool->reqlock);
              X_LOCK (pool->wrklock);
              --pool->started;
              X_UNLOCK (pool->wrklock);
              goto quit;
            }

          ++pool->idle;

          if (pool->idle <= pool->max_idle)
            /* we are allowed to pool->idle, so do so without any timeout */
            X_COND_WAIT (pool->reqwait, pool->reqlock);
          else
            {
              /* initialise timeout once */
              if (!ts.tv_sec)
                ts.tv_sec = time (0) + pool->idle_timeout;

              if (X_COND_TIMEDWAIT (pool->reqwait, pool->reqlock, ts) == ETIMEDOUT)
                ts.tv_sec = 1; /* assuming this is not a value computed above.,.. */
            }

          --pool->idle;
        }

      --pool->nready;

      X_UNLOCK (pool->reqlock);
     
      if (ecb_expect_false (req->type == ETP_TYPE_QUIT))
        goto quit;

      ETP_EXECUTE (self, req);

      X_LOCK (pool->reslock);

      ++pool->npending;

      if (!reqq_push (&pool->res_queue, req))
        ETP_WANT_POLL (pool);

      etp_worker_clear (self);

      X_UNLOCK (pool->reslock);
    }

quit:
  free (req);

  X_LOCK (pool->wrklock);
  etp_worker_free (self);
  X_UNLOCK (pool->wrklock);

  return 0;
}

static void ecb_cold
etp_start_thread (etp_pool pool)
{
  etp_worker *wrk = calloc (1, sizeof (etp_worker));

  /*TODO*/
  assert (("unable to allocate worker thread data", wrk));

  wrk->pool = pool;

  X_LOCK (pool->wrklock);

  if (xthread_create (&wrk->tid, etp_proc, (void *)wrk))
    {
      wrk->prev = &pool->wrk_first;
      wrk->next = pool->wrk_first.next;
      pool->wrk_first.next->prev = wrk;
      pool->wrk_first.next = wrk;
      ++pool->started;
    }
  else
    free (wrk);

  X_UNLOCK (pool->wrklock);
}

static void
etp_maybe_start_thread (etp_pool pool)
{
  if (ecb_expect_true (etp_nthreads (pool) >= pool->wanted))
    return;
  
  /* todo: maybe use pool->idle here, but might be less exact */
  if (ecb_expect_true (0 <= (int)etp_nthreads (pool) + (int)etp_npending (pool) - (int)etp_nreqs (pool)))
    return;

  etp_start_thread (pool);
}

static void ecb_cold
etp_end_thread (etp_pool pool)
{
  ETP_REQ *req = calloc (1, sizeof (ETP_REQ)); /* will be freed by worker */

  req->type = ETP_TYPE_QUIT;
  req->pri  = ETP_PRI_MAX - ETP_PRI_MIN;

  X_LOCK (pool->reqlock);
  reqq_push (&pool->req_queue, req);
  X_COND_SIGNAL (pool->reqwait);
  X_UNLOCK (pool->reqlock);

  X_LOCK (pool->wrklock);
  --pool->started;
  X_UNLOCK (pool->wrklock);
}

ETP_API_DECL int
etp_poll (etp_pool pool)
{
  unsigned int maxreqs;
  unsigned int maxtime;
  struct timeval tv_start, tv_now;

  X_LOCK (pool->reslock);
  maxreqs = pool->max_poll_reqs;
  maxtime = pool->max_poll_time;
  X_UNLOCK (pool->reslock);

  if (maxtime)
    gettimeofday (&tv_start, 0);

  for (;;)
    {
      ETP_REQ *req;

      etp_maybe_start_thread (pool);

      X_LOCK (pool->reslock);
      req = reqq_shift (&pool->res_queue);

      if (ecb_expect_true (req))
        {
          --pool->npending;

          if (!pool->res_queue.size)
            ETP_DONE_POLL (pool);
        }

      X_UNLOCK (pool->reslock);

      if (ecb_expect_false (!req))
        return 0;

      X_LOCK (pool->reqlock);
      --pool->nreqs;
      X_UNLOCK (pool->reqlock);

      if (ecb_expect_false (req->type == ETP_TYPE_GROUP && req->size))
        {
          req->flags |= ETP_FLAG_DELAYED; /* mark request as delayed */
          continue;
        }
      else
        {
          int res = ETP_FINISH (req);
          if (ecb_expect_false (res))
            return res;
        }

      if (ecb_expect_false (maxreqs && !--maxreqs))
        break;

      if (maxtime)
        {
          gettimeofday (&tv_now, 0);

          if (etp_tvdiff (&tv_start, &tv_now) >= maxtime)
            break;
        }
    }

  errno = EAGAIN;
  return -1;
}

ETP_API_DECL void
etp_grp_cancel (etp_pool pool, ETP_REQ *grp);

ETP_API_DECL void
etp_cancel (etp_pool pool, ETP_REQ *req)
{
  req->cancelled = 1;

  etp_grp_cancel (pool, req);
}

ETP_API_DECL void
etp_grp_cancel (etp_pool pool, ETP_REQ *grp)
{
  for (grp = grp->grp_first; grp; grp = grp->grp_next)
    etp_cancel (pool, grp);
}

ETP_API_DECL void
etp_submit (etp_pool pool, ETP_REQ *req)
{
  req->pri -= ETP_PRI_MIN;

  if (ecb_expect_false (req->pri < ETP_PRI_MIN - ETP_PRI_MIN)) req->pri = ETP_PRI_MIN - ETP_PRI_MIN;
  if (ecb_expect_false (req->pri > ETP_PRI_MAX - ETP_PRI_MIN)) req->pri = ETP_PRI_MAX - ETP_PRI_MIN;

  if (ecb_expect_false (req->type == ETP_TYPE_GROUP))
    {
      /* I hope this is worth it :/ */
      X_LOCK (pool->reqlock);
      ++pool->nreqs;
      X_UNLOCK (pool->reqlock);

      X_LOCK (pool->reslock);

      ++pool->npending;

      if (!reqq_push (&pool->res_queue, req))
        ETP_WANT_POLL (pool);

      X_UNLOCK (pool->reslock);
    }
  else
    {
      X_LOCK (pool->reqlock);
      ++pool->nreqs;
      ++pool->nready;
      reqq_push (&pool->req_queue, req);
      X_COND_SIGNAL (pool->reqwait);
      X_UNLOCK (pool->reqlock);

      etp_maybe_start_thread (pool);
    }
}

ETP_API_DECL void ecb_cold
etp_set_max_poll_time (etp_pool pool, double seconds)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reslock);
  pool->max_poll_time = seconds * ETP_TICKS;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
}

ETP_API_DECL void ecb_cold
etp_set_max_poll_reqs (etp_pool pool, unsigned int maxreqs)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reslock);
  pool->max_poll_reqs = maxreqs;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
}

ETP_API_DECL void ecb_cold
etp_set_max_idle (etp_pool pool, unsigned int threads)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  pool->max_idle = threads;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
}

ETP_API_DECL void ecb_cold
etp_set_idle_timeout (etp_pool pool, unsigned int seconds)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  pool->idle_timeout = seconds;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
}

ETP_API_DECL void ecb_cold
etp_set_min_parallel (etp_pool pool, unsigned int threads)
{
  if (pool->wanted < threads)
    pool->wanted = threads;
}

ETP_API_DECL void ecb_cold
etp_set_max_parallel (etp_pool pool, unsigned int threads)
{
  if (pool->wanted > threads)
    pool->wanted = threads;

  while (pool->started > pool->wanted)
    etp_end_thread (pool);
}

Revision:	1.12
Committed:	Tue Aug 14 09:29:50 2018 UTC (5 years, 9 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-4_53
Changes since 1.11:	+1 -10 lines
Log Message:	4.53
#	User	Rev	Content
1	root	1.1	/*
2			* libetp implementation
3			*
4	root	1.9	* Copyright (c) 2007,2008,2009,2010,2011,2012,2013,2015 Marc Alexander Lehmann <libetp@schmorp.de>
5	root	1.1	* All rights reserved.
6			*
7			* Redistribution and use in source and binary forms, with or without modifica-
8			* tion, are permitted provided that the following conditions are met:
9			*
10			* 1. Redistributions of source code must retain the above copyright notice,
11			* this list of conditions and the following disclaimer.
12			*
13			* 2. Redistributions in binary form must reproduce the above copyright
14			* notice, this list of conditions and the following disclaimer in the
15			* documentation and/or other materials provided with the distribution.
16			*
17			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19			* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20			* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
21			* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22			* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23			* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24			* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25			* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26			* OF THE POSSIBILITY OF SUCH DAMAGE.
27			*
28			* Alternatively, the contents of this file may be used under the terms of
29			* the GNU General Public License ("GPL") version 2 or any later version,
30			* in which case the provisions of the GPL are applicable instead of
31			* the above. If you wish to allow the use of your version of this file
32			* only under the terms of the GPL and not to allow others to use your
33			* version of this file under the BSD license, indicate your decision
34			* by deleting the provisions above and replace them with the notice
35			* and other provisions required by the GPL. If you do not delete the
36			* provisions above, a recipient may use your version of this file under
37			* either the BSD or the GPL.
38			*/
39
40			#ifndef ETP_API_DECL
41			# define ETP_API_DECL static
42			#endif
43
44			#ifndef ETP_PRI_MIN
45			# define ETP_PRI_MIN 0
46			# define ETP_PRI_MAX 0
47			#endif
48
49			#ifndef ETP_TYPE_QUIT
50			# define ETP_TYPE_QUIT 0
51			#endif
52
53			#ifndef ETP_TYPE_GROUP
54			# define ETP_TYPE_GROUP 1
55			#endif
56
57	root	1.6	#ifndef ETP_WANT_POLL
58			# define ETP_WANT_POLL(pool) pool->want_poll_cb (pool->userdata)
59			#endif
60			#ifndef ETP_DONE_POLL
61			# define ETP_DONE_POLL(pool) pool->done_poll_cb (pool->userdata)
62			#endif
63
64	root	1.1	#define ETP_NUM_PRI (ETP_PRI_MAX - ETP_PRI_MIN + 1)
65
66			#define ETP_TICKS ((1000000 + 1023) >> 10)
67
68	root	1.4	enum {
69			ETP_FLAG_GROUPADD = 0x04, /* some request was added to the group */
70			ETP_FLAG_DELAYED = 0x08, /* groiup request has been delayed */
71			};
72
73	root	1.1	/* calculate time difference in ~1/ETP_TICKS of a second */
74			ecb_inline int
75			etp_tvdiff (struct timeval tv1, struct timeval tv2)
76			{
77			return (tv2->tv_sec - tv1->tv_sec ) * ETP_TICKS
78			+ ((tv2->tv_usec - tv1->tv_usec) >> 10);
79			}
80
81	root	1.3	struct etp_tmpbuf
82			{
83			void *ptr;
84			int len;
85			};
86
87			static void *
88			etp_tmpbuf_get (struct etp_tmpbuf *buf, int len)
89			{
90			if (buf->len < len)
91			{
92			free (buf->ptr);
93			buf->ptr = malloc (buf->len = len);
94			}
95
96			return buf->ptr;
97			}
98
99	root	1.5	/*
100			* a somewhat faster data structure might be nice, but
101			* with 8 priorities this actually needs <20 insns
102			* per shift, the most expensive operation.
103			*/
104			typedef struct
105			{
106			ETP_REQ qs[ETP_NUM_PRI], qe[ETP_NUM_PRI]; /* qstart, qend */
107			int size;
108			} etp_reqq;
109
110	root	1.8	typedef struct etp_pool *etp_pool;
111
112			typedef struct etp_worker
113			{
114			etp_pool pool;
115
116			struct etp_tmpbuf tmpbuf;
117
118			/* locked by pool->wrklock */
119			struct etp_worker prev, next;
120
121			xthread_t tid;
122
123			#ifdef ETP_WORKER_COMMON
124			ETP_WORKER_COMMON
125			#endif
126			} etp_worker;
127
128	root	1.5	struct etp_pool
129			{
130	root	1.6	void *userdata;
131
132	root	1.5	etp_reqq req_queue;
133			etp_reqq res_queue;
134	root	1.6
135			unsigned int started, idle, wanted;
136
137			unsigned int max_poll_time; /* pool->reslock */
138			unsigned int max_poll_reqs; /* pool->reslock */
139
140			unsigned int nreqs; /* pool->reqlock */
141			unsigned int nready; /* pool->reqlock */
142			unsigned int npending; /* pool->reqlock */
143			unsigned int max_idle; /* maximum number of threads that can pool->idle indefinitely */
144			unsigned int idle_timeout; /* number of seconds after which an pool->idle threads exit */
145
146			void (want_poll_cb) (void userdata);
147			void (done_poll_cb) (void userdata);
148
149			xmutex_t wrklock;
150			xmutex_t reslock;
151			xmutex_t reqlock;
152			xcond_t reqwait;
153	root	1.7
154			etp_worker wrk_first;
155	root	1.5	};
156
157	root	1.6	#define ETP_WORKER_LOCK(wrk) X_LOCK (pool->wrklock)
158			#define ETP_WORKER_UNLOCK(wrk) X_UNLOCK (pool->wrklock)
159	root	1.1
160			/* worker threads management */
161
162			static void
163			etp_worker_clear (etp_worker *wrk)
164			{
165			}
166
167			static void ecb_cold
168			etp_worker_free (etp_worker *wrk)
169			{
170			free (wrk->tmpbuf.ptr);
171
172			wrk->next->prev = wrk->prev;
173			wrk->prev->next = wrk->next;
174
175			free (wrk);
176			}
177
178			ETP_API_DECL unsigned int
179	root	1.5	etp_nreqs (etp_pool pool)
180	root	1.1	{
181			int retval;
182	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
183			retval = pool->nreqs;
184			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
185	root	1.1	return retval;
186			}
187
188			ETP_API_DECL unsigned int
189	root	1.5	etp_nready (etp_pool pool)
190	root	1.1	{
191			unsigned int retval;
192
193	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
194			retval = pool->nready;
195			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
196	root	1.1
197			return retval;
198			}
199
200			ETP_API_DECL unsigned int
201	root	1.5	etp_npending (etp_pool pool)
202	root	1.1	{
203			unsigned int retval;
204
205	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
206			retval = pool->npending;
207			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
208	root	1.1
209			return retval;
210			}
211
212			ETP_API_DECL unsigned int
213	root	1.5	etp_nthreads (etp_pool pool)
214	root	1.1	{
215			unsigned int retval;
216
217	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
218			retval = pool->started;
219			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
220	root	1.1
221			return retval;
222			}
223
224			static void ecb_noinline ecb_cold
225			reqq_init (etp_reqq *q)
226			{
227			int pri;
228
229			for (pri = 0; pri < ETP_NUM_PRI; ++pri)
230			q->qs[pri] = q->qe[pri] = 0;
231
232			q->size = 0;
233			}
234
235			static int ecb_noinline
236			reqq_push (etp_reqq q, ETP_REQ req)
237			{
238			int pri = req->pri;
239			req->next = 0;
240
241			if (q->qe[pri])
242			{
243			q->qe[pri]->next = req;
244			q->qe[pri] = req;
245			}
246			else
247			q->qe[pri] = q->qs[pri] = req;
248
249			return q->size++;
250			}
251
252			static ETP_REQ * ecb_noinline
253			reqq_shift (etp_reqq *q)
254			{
255			int pri;
256
257			if (!q->size)
258			return 0;
259
260			--q->size;
261
262			for (pri = ETP_NUM_PRI; pri--; )
263			{
264	root	1.2	ETP_REQ *req = q->qs[pri];
265	root	1.1
266			if (req)
267			{
268	root	1.2	if (!(q->qs[pri] = (ETP_REQ *)req->next))
269	root	1.1	q->qe[pri] = 0;
270
271			return req;
272			}
273			}
274
275			abort ();
276			}
277
278			ETP_API_DECL int ecb_cold
279	root	1.7	etp_init (etp_pool pool, void userdata, void (want_poll)(void userdata), void (done_poll)(void *userdata))
280	root	1.1	{
281	root	1.6	X_MUTEX_CREATE (pool->wrklock);
282			X_MUTEX_CREATE (pool->reslock);
283			X_MUTEX_CREATE (pool->reqlock);
284			X_COND_CREATE (pool->reqwait);
285	root	1.1
286	root	1.5	reqq_init (&pool->req_queue);
287			reqq_init (&pool->res_queue);
288	root	1.1
289	root	1.7	pool->wrk_first.next =
290			pool->wrk_first.prev = &pool->wrk_first;
291	root	1.1
292	root	1.6	pool->started = 0;
293			pool->idle = 0;
294			pool->nreqs = 0;
295			pool->nready = 0;
296			pool->npending = 0;
297			pool->wanted = 4;
298
299			pool->max_idle = 4; /* maximum number of threads that can pool->idle indefinitely */
300			pool->idle_timeout = 10; /* number of seconds after which an pool->idle threads exit */
301	root	1.1
302	root	1.7	pool->userdata = userdata;
303	root	1.6	pool->want_poll_cb = want_poll;
304			pool->done_poll_cb = done_poll;
305	root	1.1
306			return 0;
307			}
308
309	root	1.4	static void ecb_noinline ecb_cold
310			etp_proc_init (void)
311			{
312			#if HAVE_PRCTL_SET_NAME
313			/* provide a more sensible "thread name" */
314	root	1.12	char name[16 + 1];
315	root	1.4	const int namelen = sizeof (name) - 1;
316			int len;
317
318			prctl (PR_GET_NAME, (unsigned long)name, 0, 0, 0);
319			name [namelen] = 0;
320			len = strlen (name);
321			strcpy (name + (len <= namelen - 4 ? len : namelen - 4), "/eio");
322			prctl (PR_SET_NAME, (unsigned long)name, 0, 0, 0);
323			#endif
324			}
325
326			X_THREAD_PROC (etp_proc)
327			{
328			ETP_REQ *req;
329			struct timespec ts;
330			etp_worker self = (etp_worker )thr_arg;
331	root	1.5	etp_pool pool = self->pool;
332	root	1.4
333			etp_proc_init ();
334
335			/* try to distribute timeouts somewhat evenly */
336			ts.tv_nsec = ((unsigned long)self & 1023UL) * (1000000000UL / 1024UL);
337
338			for (;;)
339			{
340			ts.tv_sec = 0;
341
342	root	1.6	X_LOCK (pool->reqlock);
343	root	1.4
344			for (;;)
345			{
346	root	1.5	req = reqq_shift (&pool->req_queue);
347	root	1.4
348	root	1.9	if (ecb_expect_true (req))
349	root	1.4	break;
350
351			if (ts.tv_sec == 1) /* no request, but timeout detected, let's quit */
352			{
353	root	1.6	X_UNLOCK (pool->reqlock);
354			X_LOCK (pool->wrklock);
355			--pool->started;
356			X_UNLOCK (pool->wrklock);
357	root	1.4	goto quit;
358			}
359
360	root	1.6	++pool->idle;
361	root	1.4
362	root	1.6	if (pool->idle <= pool->max_idle)
363			/* we are allowed to pool->idle, so do so without any timeout */
364			X_COND_WAIT (pool->reqwait, pool->reqlock);
365	root	1.4	else
366			{
367			/* initialise timeout once */
368			if (!ts.tv_sec)
369	root	1.6	ts.tv_sec = time (0) + pool->idle_timeout;
370	root	1.4
371	root	1.6	if (X_COND_TIMEDWAIT (pool->reqwait, pool->reqlock, ts) == ETIMEDOUT)
372	root	1.4	ts.tv_sec = 1; /* assuming this is not a value computed above.,.. */
373			}
374
375	root	1.6	--pool->idle;
376	root	1.4	}
377
378	root	1.6	--pool->nready;
379	root	1.4
380	root	1.6	X_UNLOCK (pool->reqlock);
381	root	1.4
382	root	1.9	if (ecb_expect_false (req->type == ETP_TYPE_QUIT))
383	root	1.4	goto quit;
384
385			ETP_EXECUTE (self, req);
386
387	root	1.6	X_LOCK (pool->reslock);
388	root	1.4
389	root	1.6	++pool->npending;
390	root	1.4
391	root	1.6	if (!reqq_push (&pool->res_queue, req))
392	root	1.9	ETP_WANT_POLL (pool);
393	root	1.4
394			etp_worker_clear (self);
395
396	root	1.6	X_UNLOCK (pool->reslock);
397	root	1.4	}
398
399			quit:
400			free (req);
401
402	root	1.6	X_LOCK (pool->wrklock);
403	root	1.4	etp_worker_free (self);
404	root	1.6	X_UNLOCK (pool->wrklock);
405	root	1.4
406			return 0;
407			}
408	root	1.1
409			static void ecb_cold
410	root	1.5	etp_start_thread (etp_pool pool)
411	root	1.1	{
412			etp_worker *wrk = calloc (1, sizeof (etp_worker));
413
414			/TODO/
415			assert (("unable to allocate worker thread data", wrk));
416
417	root	1.5	wrk->pool = pool;
418
419	root	1.6	X_LOCK (pool->wrklock);
420	root	1.1
421			if (xthread_create (&wrk->tid, etp_proc, (void *)wrk))
422			{
423	root	1.8	wrk->prev = &pool->wrk_first;
424	root	1.7	wrk->next = pool->wrk_first.next;
425			pool->wrk_first.next->prev = wrk;
426			pool->wrk_first.next = wrk;
427	root	1.6	++pool->started;
428	root	1.1	}
429			else
430			free (wrk);
431
432	root	1.6	X_UNLOCK (pool->wrklock);
433	root	1.1	}
434
435			static void
436	root	1.5	etp_maybe_start_thread (etp_pool pool)
437	root	1.1	{
438	root	1.6	if (ecb_expect_true (etp_nthreads (pool) >= pool->wanted))
439	root	1.1	return;
440
441	root	1.6	/* todo: maybe use pool->idle here, but might be less exact */
442	root	1.5	if (ecb_expect_true (0 <= (int)etp_nthreads (pool) + (int)etp_npending (pool) - (int)etp_nreqs (pool)))
443	root	1.1	return;
444
445	root	1.5	etp_start_thread (pool);
446	root	1.1	}
447
448			static void ecb_cold
449	root	1.5	etp_end_thread (etp_pool pool)
450	root	1.1	{
451	root	1.2	ETP_REQ req = calloc (1, sizeof (ETP_REQ)); / will be freed by worker */
452	root	1.1
453			req->type = ETP_TYPE_QUIT;
454			req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
455
456	root	1.6	X_LOCK (pool->reqlock);
457	root	1.5	reqq_push (&pool->req_queue, req);
458	root	1.6	X_COND_SIGNAL (pool->reqwait);
459			X_UNLOCK (pool->reqlock);
460	root	1.1
461	root	1.6	X_LOCK (pool->wrklock);
462			--pool->started;
463			X_UNLOCK (pool->wrklock);
464	root	1.1	}
465
466			ETP_API_DECL int
467	root	1.5	etp_poll (etp_pool pool)
468	root	1.1	{
469			unsigned int maxreqs;
470			unsigned int maxtime;
471			struct timeval tv_start, tv_now;
472
473	root	1.6	X_LOCK (pool->reslock);
474			maxreqs = pool->max_poll_reqs;
475			maxtime = pool->max_poll_time;
476			X_UNLOCK (pool->reslock);
477	root	1.1
478			if (maxtime)
479			gettimeofday (&tv_start, 0);
480
481			for (;;)
482			{
483			ETP_REQ *req;
484
485	root	1.5	etp_maybe_start_thread (pool);
486	root	1.1
487	root	1.6	X_LOCK (pool->reslock);
488	root	1.5	req = reqq_shift (&pool->res_queue);
489	root	1.1
490	root	1.9	if (ecb_expect_true (req))
491	root	1.1	{
492	root	1.6	--pool->npending;
493	root	1.1
494	root	1.6	if (!pool->res_queue.size)
495	root	1.9	ETP_DONE_POLL (pool);
496	root	1.1	}
497
498	root	1.6	X_UNLOCK (pool->reslock);
499	root	1.1
500	root	1.9	if (ecb_expect_false (!req))
501	root	1.1	return 0;
502
503	root	1.6	X_LOCK (pool->reqlock);
504			--pool->nreqs;
505			X_UNLOCK (pool->reqlock);
506	root	1.1
507			if (ecb_expect_false (req->type == ETP_TYPE_GROUP && req->size))
508			{
509	root	1.4	req->flags \|= ETP_FLAG_DELAYED; /* mark request as delayed */
510	root	1.1	continue;
511			}
512			else
513			{
514			int res = ETP_FINISH (req);
515			if (ecb_expect_false (res))
516			return res;
517			}
518
519			if (ecb_expect_false (maxreqs && !--maxreqs))
520			break;
521
522			if (maxtime)
523			{
524			gettimeofday (&tv_now, 0);
525
526			if (etp_tvdiff (&tv_start, &tv_now) >= maxtime)
527			break;
528			}
529			}
530
531			errno = EAGAIN;
532			return -1;
533			}
534
535			ETP_API_DECL void
536	root	1.5	etp_grp_cancel (etp_pool pool, ETP_REQ *grp);
537	root	1.1
538			ETP_API_DECL void
539	root	1.5	etp_cancel (etp_pool pool, ETP_REQ *req)
540	root	1.1	{
541			req->cancelled = 1;
542
543	root	1.5	etp_grp_cancel (pool, req);
544	root	1.1	}
545
546			ETP_API_DECL void
547	root	1.5	etp_grp_cancel (etp_pool pool, ETP_REQ *grp)
548	root	1.1	{
549			for (grp = grp->grp_first; grp; grp = grp->grp_next)
550	root	1.5	etp_cancel (pool, grp);
551	root	1.1	}
552
553			ETP_API_DECL void
554	root	1.5	etp_submit (etp_pool pool, ETP_REQ *req)
555	root	1.1	{
556			req->pri -= ETP_PRI_MIN;
557
558			if (ecb_expect_false (req->pri < ETP_PRI_MIN - ETP_PRI_MIN)) req->pri = ETP_PRI_MIN - ETP_PRI_MIN;
559			if (ecb_expect_false (req->pri > ETP_PRI_MAX - ETP_PRI_MIN)) req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
560
561			if (ecb_expect_false (req->type == ETP_TYPE_GROUP))
562			{
563			/* I hope this is worth it :/ */
564	root	1.6	X_LOCK (pool->reqlock);
565			++pool->nreqs;
566			X_UNLOCK (pool->reqlock);
567	root	1.1
568	root	1.6	X_LOCK (pool->reslock);
569	root	1.1
570	root	1.6	++pool->npending;
571	root	1.1
572	root	1.6	if (!reqq_push (&pool->res_queue, req))
573			ETP_WANT_POLL (pool);
574	root	1.1
575	root	1.6	X_UNLOCK (pool->reslock);
576	root	1.1	}
577			else
578			{
579	root	1.6	X_LOCK (pool->reqlock);
580			++pool->nreqs;
581			++pool->nready;
582	root	1.5	reqq_push (&pool->req_queue, req);
583	root	1.6	X_COND_SIGNAL (pool->reqwait);
584			X_UNLOCK (pool->reqlock);
585	root	1.1
586	root	1.5	etp_maybe_start_thread (pool);
587	root	1.1	}
588			}
589
590			ETP_API_DECL void ecb_cold
591	root	1.10	etp_set_max_poll_time (etp_pool pool, double seconds)
592	root	1.1	{
593	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reslock);
594	root	1.10	pool->max_poll_time = seconds * ETP_TICKS;
595	root	1.6	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
596	root	1.1	}
597
598			ETP_API_DECL void ecb_cold
599	root	1.5	etp_set_max_poll_reqs (etp_pool pool, unsigned int maxreqs)
600	root	1.1	{
601	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reslock);
602			pool->max_poll_reqs = maxreqs;
603			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
604	root	1.1	}
605
606			ETP_API_DECL void ecb_cold
607	root	1.10	etp_set_max_idle (etp_pool pool, unsigned int threads)
608	root	1.1	{
609	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
610	root	1.10	pool->max_idle = threads;
611	root	1.6	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
612	root	1.1	}
613
614			ETP_API_DECL void ecb_cold
615	root	1.5	etp_set_idle_timeout (etp_pool pool, unsigned int seconds)
616	root	1.1	{
617	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
618			pool->idle_timeout = seconds;
619			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
620	root	1.1	}
621
622			ETP_API_DECL void ecb_cold
623	root	1.10	etp_set_min_parallel (etp_pool pool, unsigned int threads)
624	root	1.1	{
625	root	1.10	if (pool->wanted < threads)
626			pool->wanted = threads;
627	root	1.1	}
628
629			ETP_API_DECL void ecb_cold
630	root	1.10	etp_set_max_parallel (etp_pool pool, unsigned int threads)
631	root	1.1	{
632	root	1.10	if (pool->wanted > threads)
633			pool->wanted = threads;
634	root	1.1
635	root	1.6	while (pool->started > pool->wanted)
636	root	1.5	etp_end_thread (pool);
637	root	1.1	}
638