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.
 */

#if HAVE_SYS_PRCTL_H
# include <sys/prctl.h>
#endif

#ifdef EIO_STACKSIZE
# define X_STACKSIZE EIO_STACKSIZE
#endif
#include "xthread.h"

#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:	1.14
Committed:	Tue Aug 14 11:47:01 2018 UTC (5 years, 8 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-4_6, rel-4_7, rel-4_81, rel-4_80, rel-4_78, rel-4_79, rel-4_54, rel-4_74, rel-4_75, rel-4_76, rel-4_77, rel-4_71, rel-4_72, rel-4_73, HEAD
Changes since 1.13:	+5 -0 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* libetp implementation
3	*
4	* Copyright (c) 2007,2008,2009,2010,2011,2012,2013,2015 Marc Alexander Lehmann <libetp@schmorp.de>
5	* 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	#if HAVE_SYS_PRCTL_H
41	# include <sys/prctl.h>
42	#endif
43
44	#ifdef EIO_STACKSIZE
45	# define X_STACKSIZE EIO_STACKSIZE
46	#endif
47	#include "xthread.h"
48
49	#ifndef ETP_API_DECL
50	# define ETP_API_DECL static
51	#endif
52
53	#ifndef ETP_PRI_MIN
54	# define ETP_PRI_MIN 0
55	# define ETP_PRI_MAX 0
56	#endif
57
58	#ifndef ETP_TYPE_QUIT
59	# define ETP_TYPE_QUIT 0
60	#endif
61
62	#ifndef ETP_TYPE_GROUP
63	# define ETP_TYPE_GROUP 1
64	#endif
65
66	#ifndef ETP_WANT_POLL
67	# define ETP_WANT_POLL(pool) pool->want_poll_cb (pool->userdata)
68	#endif
69	#ifndef ETP_DONE_POLL
70	# define ETP_DONE_POLL(pool) pool->done_poll_cb (pool->userdata)
71	#endif
72
73	#define ETP_NUM_PRI (ETP_PRI_MAX - ETP_PRI_MIN + 1)
74
75	#define ETP_TICKS ((1000000 + 1023) >> 10)
76
77	enum {
78	ETP_FLAG_GROUPADD = 0x04, /* some request was added to the group */
79	ETP_FLAG_DELAYED = 0x08, /* groiup request has been delayed */
80	};
81
82	/* calculate time difference in ~1/ETP_TICKS of a second */
83	ecb_inline int
84	etp_tvdiff (struct timeval tv1, struct timeval tv2)
85	{
86	return (tv2->tv_sec - tv1->tv_sec ) * ETP_TICKS
87	+ ((tv2->tv_usec - tv1->tv_usec) >> 10);
88	}
89
90	struct etp_tmpbuf
91	{
92	void *ptr;
93	int len;
94	};
95
96	static void *
97	etp_tmpbuf_get (struct etp_tmpbuf *buf, int len)
98	{
99	if (buf->len < len)
100	{
101	free (buf->ptr);
102	buf->ptr = malloc (buf->len = len);
103	}
104
105	return buf->ptr;
106	}
107
108	/*
109	* a somewhat faster data structure might be nice, but
110	* with 8 priorities this actually needs <20 insns
111	* per shift, the most expensive operation.
112	*/
113	typedef struct
114	{
115	ETP_REQ qs[ETP_NUM_PRI], qe[ETP_NUM_PRI]; /* qstart, qend */
116	int size;
117	} etp_reqq;
118
119	typedef struct etp_pool *etp_pool;
120
121	typedef struct etp_worker
122	{
123	etp_pool pool;
124
125	struct etp_tmpbuf tmpbuf;
126
127	/* locked by pool->wrklock */
128	struct etp_worker prev, next;
129
130	xthread_t tid;
131
132	#ifdef ETP_WORKER_COMMON
133	ETP_WORKER_COMMON
134	#endif
135	} etp_worker;
136
137	struct etp_pool
138	{
139	void *userdata;
140
141	etp_reqq req_queue;
142	etp_reqq res_queue;
143
144	unsigned int started, idle, wanted;
145
146	unsigned int max_poll_time; /* pool->reslock */
147	unsigned int max_poll_reqs; /* pool->reslock */
148
149	unsigned int nreqs; /* pool->reqlock */
150	unsigned int nready; /* pool->reqlock */
151	unsigned int npending; /* pool->reqlock */
152	unsigned int max_idle; /* maximum number of threads that can pool->idle indefinitely */
153	unsigned int idle_timeout; /* number of seconds after which an pool->idle threads exit */
154
155	void (want_poll_cb) (void userdata);
156	void (done_poll_cb) (void userdata);
157
158	xmutex_t wrklock;
159	xmutex_t reslock;
160	xmutex_t reqlock;
161	xcond_t reqwait;
162
163	etp_worker wrk_first;
164	};
165
166	#define ETP_WORKER_LOCK(wrk) X_LOCK (pool->wrklock)
167	#define ETP_WORKER_UNLOCK(wrk) X_UNLOCK (pool->wrklock)
168
169	/* worker threads management */
170
171	static void
172	etp_worker_clear (etp_worker *wrk)
173	{
174	}
175
176	static void ecb_cold
177	etp_worker_free (etp_worker *wrk)
178	{
179	free (wrk->tmpbuf.ptr);
180
181	wrk->next->prev = wrk->prev;
182	wrk->prev->next = wrk->next;
183
184	free (wrk);
185	}
186
187	ETP_API_DECL unsigned int
188	etp_nreqs (etp_pool pool)
189	{
190	int retval;
191	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
192	retval = pool->nreqs;
193	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
194	return retval;
195	}
196
197	ETP_API_DECL unsigned int
198	etp_nready (etp_pool pool)
199	{
200	unsigned int retval;
201
202	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
203	retval = pool->nready;
204	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
205
206	return retval;
207	}
208
209	ETP_API_DECL unsigned int
210	etp_npending (etp_pool pool)
211	{
212	unsigned int retval;
213
214	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
215	retval = pool->npending;
216	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
217
218	return retval;
219	}
220
221	ETP_API_DECL unsigned int
222	etp_nthreads (etp_pool pool)
223	{
224	unsigned int retval;
225
226	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
227	retval = pool->started;
228	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
229
230	return retval;
231	}
232
233	static void ecb_noinline ecb_cold
234	reqq_init (etp_reqq *q)
235	{
236	int pri;
237
238	for (pri = 0; pri < ETP_NUM_PRI; ++pri)
239	q->qs[pri] = q->qe[pri] = 0;
240
241	q->size = 0;
242	}
243
244	static int ecb_noinline
245	reqq_push (etp_reqq q, ETP_REQ req)
246	{
247	int pri = req->pri;
248	req->next = 0;
249
250	if (q->qe[pri])
251	{
252	q->qe[pri]->next = req;
253	q->qe[pri] = req;
254	}
255	else
256	q->qe[pri] = q->qs[pri] = req;
257
258	return q->size++;
259	}
260
261	static ETP_REQ * ecb_noinline
262	reqq_shift (etp_reqq *q)
263	{
264	int pri;
265
266	if (!q->size)
267	return 0;
268
269	--q->size;
270
271	for (pri = ETP_NUM_PRI; pri--; )
272	{
273	ETP_REQ *req = q->qs[pri];
274
275	if (req)
276	{
277	if (!(q->qs[pri] = (ETP_REQ *)req->next))
278	q->qe[pri] = 0;
279
280	return req;
281	}
282	}
283
284	abort ();
285	}
286
287	ETP_API_DECL int ecb_cold
288	etp_init (etp_pool pool, void userdata, void (want_poll)(void userdata), void (done_poll)(void *userdata))
289	{
290	X_MUTEX_CREATE (pool->wrklock);
291	X_MUTEX_CREATE (pool->reslock);
292	X_MUTEX_CREATE (pool->reqlock);
293	X_COND_CREATE (pool->reqwait);
294
295	reqq_init (&pool->req_queue);
296	reqq_init (&pool->res_queue);
297
298	pool->wrk_first.next =
299	pool->wrk_first.prev = &pool->wrk_first;
300
301	pool->started = 0;
302	pool->idle = 0;
303	pool->nreqs = 0;
304	pool->nready = 0;
305	pool->npending = 0;
306	pool->wanted = 4;
307
308	pool->max_idle = 4; /* maximum number of threads that can pool->idle indefinitely */
309	pool->idle_timeout = 10; /* number of seconds after which an pool->idle threads exit */
310
311	pool->userdata = userdata;
312	pool->want_poll_cb = want_poll;
313	pool->done_poll_cb = done_poll;
314
315	return 0;
316	}
317
318	static void ecb_noinline ecb_cold
319	etp_proc_init (void)
320	{
321	#if HAVE_PRCTL_SET_NAME
322	/* provide a more sensible "thread name" */
323	char name[16 + 1];
324	const int namelen = sizeof (name) - 1;
325	int len;
326
327	prctl (PR_GET_NAME, (unsigned long)name, 0, 0, 0);
328	name [namelen] = 0;
329	len = strlen (name);
330	strcpy (name + (len <= namelen - 4 ? len : namelen - 4), "/eio");
331	prctl (PR_SET_NAME, (unsigned long)name, 0, 0, 0);
332	#endif
333	}
334
335	X_THREAD_PROC (etp_proc)
336	{
337	ETP_REQ *req;
338	struct timespec ts;
339	etp_worker self = (etp_worker )thr_arg;
340	etp_pool pool = self->pool;
341
342	etp_proc_init ();
343
344	/* try to distribute timeouts somewhat evenly */
345	ts.tv_nsec = ((unsigned long)self & 1023UL) * (1000000000UL / 1024UL);
346
347	for (;;)
348	{
349	ts.tv_sec = 0;
350
351	X_LOCK (pool->reqlock);
352
353	for (;;)
354	{
355	req = reqq_shift (&pool->req_queue);
356
357	if (ecb_expect_true (req))
358	break;
359
360	if (ts.tv_sec == 1) /* no request, but timeout detected, let's quit */
361	{
362	X_UNLOCK (pool->reqlock);
363	X_LOCK (pool->wrklock);
364	--pool->started;
365	X_UNLOCK (pool->wrklock);
366	goto quit;
367	}
368
369	++pool->idle;
370
371	if (pool->idle <= pool->max_idle)
372	/* we are allowed to pool->idle, so do so without any timeout */
373	X_COND_WAIT (pool->reqwait, pool->reqlock);
374	else
375	{
376	/* initialise timeout once */
377	if (!ts.tv_sec)
378	ts.tv_sec = time (0) + pool->idle_timeout;
379
380	if (X_COND_TIMEDWAIT (pool->reqwait, pool->reqlock, ts) == ETIMEDOUT)
381	ts.tv_sec = 1; /* assuming this is not a value computed above.,.. */
382	}
383
384	--pool->idle;
385	}
386
387	--pool->nready;
388
389	X_UNLOCK (pool->reqlock);
390
391	if (ecb_expect_false (req->type == ETP_TYPE_QUIT))
392	goto quit;
393
394	ETP_EXECUTE (self, req);
395
396	X_LOCK (pool->reslock);
397
398	++pool->npending;
399
400	if (!reqq_push (&pool->res_queue, req))
401	ETP_WANT_POLL (pool);
402
403	etp_worker_clear (self);
404
405	X_UNLOCK (pool->reslock);
406	}
407
408	quit:
409	free (req);
410
411	X_LOCK (pool->wrklock);
412	etp_worker_free (self);
413	X_UNLOCK (pool->wrklock);
414
415	return 0;
416	}
417
418	static void ecb_cold
419	etp_start_thread (etp_pool pool)
420	{
421	etp_worker *wrk = calloc (1, sizeof (etp_worker));
422
423	/TODO/
424	assert (("unable to allocate worker thread data", wrk));
425
426	wrk->pool = pool;
427
428	X_LOCK (pool->wrklock);
429
430	if (xthread_create (&wrk->tid, etp_proc, (void *)wrk))
431	{
432	wrk->prev = &pool->wrk_first;
433	wrk->next = pool->wrk_first.next;
434	pool->wrk_first.next->prev = wrk;
435	pool->wrk_first.next = wrk;
436	++pool->started;
437	}
438	else
439	free (wrk);
440
441	X_UNLOCK (pool->wrklock);
442	}
443
444	static void
445	etp_maybe_start_thread (etp_pool pool)
446	{
447	if (ecb_expect_true (etp_nthreads (pool) >= pool->wanted))
448	return;
449
450	/* todo: maybe use pool->idle here, but might be less exact */
451	if (ecb_expect_true (0 <= (int)etp_nthreads (pool) + (int)etp_npending (pool) - (int)etp_nreqs (pool)))
452	return;
453
454	etp_start_thread (pool);
455	}
456
457	static void ecb_cold
458	etp_end_thread (etp_pool pool)
459	{
460	ETP_REQ req = calloc (1, sizeof (ETP_REQ)); / will be freed by worker */
461
462	req->type = ETP_TYPE_QUIT;
463	req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
464
465	X_LOCK (pool->reqlock);
466	reqq_push (&pool->req_queue, req);
467	X_COND_SIGNAL (pool->reqwait);
468	X_UNLOCK (pool->reqlock);
469
470	X_LOCK (pool->wrklock);
471	--pool->started;
472	X_UNLOCK (pool->wrklock);
473	}
474
475	ETP_API_DECL int
476	etp_poll (etp_pool pool)
477	{
478	unsigned int maxreqs;
479	unsigned int maxtime;
480	struct timeval tv_start, tv_now;
481
482	X_LOCK (pool->reslock);
483	maxreqs = pool->max_poll_reqs;
484	maxtime = pool->max_poll_time;
485	X_UNLOCK (pool->reslock);
486
487	if (maxtime)
488	gettimeofday (&tv_start, 0);
489
490	for (;;)
491	{
492	ETP_REQ *req;
493
494	etp_maybe_start_thread (pool);
495
496	X_LOCK (pool->reslock);
497	req = reqq_shift (&pool->res_queue);
498
499	if (ecb_expect_true (req))
500	{
501	--pool->npending;
502
503	if (!pool->res_queue.size)
504	ETP_DONE_POLL (pool);
505	}
506
507	X_UNLOCK (pool->reslock);
508
509	if (ecb_expect_false (!req))
510	return 0;
511
512	X_LOCK (pool->reqlock);
513	--pool->nreqs;
514	X_UNLOCK (pool->reqlock);
515
516	if (ecb_expect_false (req->type == ETP_TYPE_GROUP && req->size))
517	{
518	req->flags \|= ETP_FLAG_DELAYED; /* mark request as delayed */
519	continue;
520	}
521	else
522	{
523	int res = ETP_FINISH (req);
524	if (ecb_expect_false (res))
525	return res;
526	}
527
528	if (ecb_expect_false (maxreqs && !--maxreqs))
529	break;
530
531	if (maxtime)
532	{
533	gettimeofday (&tv_now, 0);
534
535	if (etp_tvdiff (&tv_start, &tv_now) >= maxtime)
536	break;
537	}
538	}
539
540	errno = EAGAIN;
541	return -1;
542	}
543
544	ETP_API_DECL void
545	etp_grp_cancel (etp_pool pool, ETP_REQ *grp);
546
547	ETP_API_DECL void
548	etp_cancel (etp_pool pool, ETP_REQ *req)
549	{
550	req->cancelled = 1;
551
552	etp_grp_cancel (pool, req);
553	}
554
555	ETP_API_DECL void
556	etp_grp_cancel (etp_pool pool, ETP_REQ *grp)
557	{
558	for (grp = grp->grp_first; grp; grp = grp->grp_next)
559	etp_cancel (pool, grp);
560	}
561
562	ETP_API_DECL void
563	etp_submit (etp_pool pool, ETP_REQ *req)
564	{
565	req->pri -= ETP_PRI_MIN;
566
567	if (ecb_expect_false (req->pri < ETP_PRI_MIN - ETP_PRI_MIN)) req->pri = ETP_PRI_MIN - ETP_PRI_MIN;
568	if (ecb_expect_false (req->pri > ETP_PRI_MAX - ETP_PRI_MIN)) req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
569
570	if (ecb_expect_false (req->type == ETP_TYPE_GROUP))
571	{
572	/* I hope this is worth it :/ */
573	X_LOCK (pool->reqlock);
574	++pool->nreqs;
575	X_UNLOCK (pool->reqlock);
576
577	X_LOCK (pool->reslock);
578
579	++pool->npending;
580
581	if (!reqq_push (&pool->res_queue, req))
582	ETP_WANT_POLL (pool);
583
584	X_UNLOCK (pool->reslock);
585	}
586	else
587	{
588	X_LOCK (pool->reqlock);
589	++pool->nreqs;
590	++pool->nready;
591	reqq_push (&pool->req_queue, req);
592	X_COND_SIGNAL (pool->reqwait);
593	X_UNLOCK (pool->reqlock);
594
595	etp_maybe_start_thread (pool);
596	}
597	}
598
599	ETP_API_DECL void ecb_cold
600	etp_set_max_poll_time (etp_pool pool, double seconds)
601	{
602	if (WORDACCESS_UNSAFE) X_LOCK (pool->reslock);
603	pool->max_poll_time = seconds * ETP_TICKS;
604	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
605	}
606
607	ETP_API_DECL void ecb_cold
608	etp_set_max_poll_reqs (etp_pool pool, unsigned int maxreqs)
609	{
610	if (WORDACCESS_UNSAFE) X_LOCK (pool->reslock);
611	pool->max_poll_reqs = maxreqs;
612	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
613	}
614
615	ETP_API_DECL void ecb_cold
616	etp_set_max_idle (etp_pool pool, unsigned int threads)
617	{
618	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
619	pool->max_idle = threads;
620	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
621	}
622
623	ETP_API_DECL void ecb_cold
624	etp_set_idle_timeout (etp_pool pool, unsigned int seconds)
625	{
626	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
627	pool->idle_timeout = seconds;
628	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
629	}
630
631	ETP_API_DECL void ecb_cold
632	etp_set_min_parallel (etp_pool pool, unsigned int threads)
633	{
634	if (pool->wanted < threads)
635	pool->wanted = threads;
636	}
637
638	ETP_API_DECL void ecb_cold
639	etp_set_max_parallel (etp_pool pool, unsigned int threads)
640	{
641	if (pool->wanted > threads)
642	pool->wanted = threads;
643
644	while (pool->started > pool->wanted)
645	etp_end_thread (pool);
646	}
647