dnxJobList.c

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/*--------------------------------------------------------------------------

   Copyright (c) 2006-2010, Intellectual Reserve, Inc. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 2 as
   published by the Free Software Foundation.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  --------------------------------------------------------------------------*/

#include "dnxJobList.h"

#include "dnxError.h"
#include "dnxDebug.h"
#include "dnxLogging.h"
#include "dnxTimer.h"

#include <sys/time.h>

#define DNX_JOBLIST_TIMEOUT   5     
#define DNX_TIMER_SLEEP       5000  
DnxJobList * joblist; // Fwd declaration

typedef struct iDnxJobList_
{
   DnxNewJob * list;       
   unsigned long size;     
   unsigned long head;     
   unsigned long tail;     
   unsigned long dhead;    
   pthread_mutex_t mut;    
   pthread_cond_t cond;    
   DnxTimer * timer;       
} iDnxJobList;

/*--------------------------------------------------------------------------
                                 INTERFACE
  --------------------------------------------------------------------------*/

int dnxJobListAdd(DnxJobList * pJobList, DnxNewJob * pJob)
{
   iDnxJobList * ilist = (iDnxJobList *)pJobList;
   unsigned long tail;
   int ret = DNX_OK;

   assert(pJobList && pJob);

   DNX_PT_MUTEX_LOCK(&ilist->mut);

   tail = ilist->tail;

   // verify space in the job list
   if (ilist->list[tail].state && (tail = (tail + 1) % ilist->size) == ilist->head)
   {
      dnxLog("dnxJobListAdd: Out of job slots (max=%lu): %s.",
            ilist->size, pJob->cmd);
      ret = DNX_ERR_CAPACITY;
   }
   else
   {
      // add the slot index to the Job's XID - this allows us to index
      //    the job list using the returned result's XID.objSlot field
      pJob->xid.objSlot = tail;
      pJob->state = DNX_JOB_PENDING;

      // add this job to the job list
      memcpy(&ilist->list[tail], pJob, sizeof *pJob);

      // update dispatch head index
      if (ilist->list[ilist->tail].state != DNX_JOB_PENDING)
         ilist->dhead = tail;

      ilist->tail = tail;

      dnxDebug(8, "dnxJobListAdd: Job [%lu,%lu]: Head=%lu, DHead=%lu, Tail=%lu.",
            pJob->xid.objSerial, pJob->xid.objSlot, ilist->head, ilist->dhead,
            ilist->tail);

      pthread_cond_signal(&ilist->cond);  // signal that a new job is available
   }

   DNX_PT_MUTEX_UNLOCK(&ilist->mut);

   return ret;
}

//----------------------------------------------------------------------------

int dnxJobListExpire(DnxJobList * pJobList, DnxNewJob * pExpiredJobs,
      int * totalJobs)
{
   iDnxJobList * ilist = (iDnxJobList *)pJobList;
   unsigned long current;
   DnxNewJob * pJob;
   int jobCount;
   time_t now;

   assert(pJobList && pExpiredJobs && totalJobs && *totalJobs > 0);

   DNX_PT_MUTEX_LOCK(&ilist->mut);

   // get the current time (after we acquire the lock! In case we had to wait)
   now = time(0);

   // walk the entire job list - InProgress and Pending jobs (in that order)
   current = ilist->head;
   jobCount = 0;
   while (jobCount < *totalJobs)
   {
      // only examine jobs that are either awaiting dispatch or results
      if ((pJob = &ilist->list[current])->state == DNX_JOB_INPROGRESS
            || pJob->state == DNX_JOB_PENDING)
      {
         // check the job's expiration stamp
         if (pJob->expires > now)
            break;   // Bail-out: this job hasn't expired yet

         // job has expired - add it to the expired job list
         memcpy(&pExpiredJobs[jobCount], pJob, sizeof(DnxNewJob));

         pJob->state = DNX_JOB_NULL;

         jobCount++;
      }

      // bail-out if this was the job list tail
      if (current == ilist->tail)
         break;

      // increment the job list index
      current = (current + 1) % ilist->size;
   }

   ilist->head = current;

   // if this job is awaiting dispatch, then it is the new dispatch head
   if (ilist->list[current].state != DNX_JOB_INPROGRESS)
      ilist->dhead = current;

   // update the total jobs in the expired job list
   *totalJobs = jobCount;

   DNX_PT_MUTEX_UNLOCK(&ilist->mut);

   return DNX_OK;
}

//----------------------------------------------------------------------------

int dnxJobListDispatch(DnxJobList * pJobList, DnxNewJob * pJob)
{
   iDnxJobList * ilist = (iDnxJobList *)pJobList;
   unsigned long current;
   int ret = 0;

   assert(pJobList && pJob);

   DNX_PT_MUTEX_LOCK(&ilist->mut);

   // start at current dispatch head
   current = ilist->dhead;

   // see if we have a pending job
   while (ilist->list[current].state != DNX_JOB_PENDING)
   {
      struct timeval now;
      struct timespec timeout;

      gettimeofday(&now, 0);
      timeout.tv_sec = now.tv_sec + DNX_JOBLIST_TIMEOUT;
      timeout.tv_nsec = now.tv_usec * 1000;

      dnxDebug(8, "dnxJobListDispatch: BEFORE: Head=%lu, DHead=%lu, Tail=%lu.",
            ilist->head, ilist->dhead, ilist->tail);

      // wait on the condition variable if there are no pending jobs
      if ((ret = pthread_cond_timedwait(&ilist->cond, &ilist->mut,
            &timeout)) == ETIMEDOUT)
         break;

      current = ilist->dhead;
   }

   if (ret == 0)
   {
      // transition this job's state to InProgress
      ilist->list[current].state = DNX_JOB_INPROGRESS;

      // make a copy for the Dispatcher
      memcpy(pJob, &ilist->list[current], sizeof *pJob);

      // update the dispatch head
      if (ilist->dhead != ilist->tail)
         ilist->dhead = (current + 1) % ilist->size;

      dnxDebug(8, "dnxJobListDispatch: AFTER: Job [%lu,%lu]; Head=%lu, DHead=%lu, Tail=%lu.",
            pJob->xid.objSerial, pJob->xid.objSlot, ilist->head, ilist->dhead, ilist->tail);
   }

   DNX_PT_MUTEX_UNLOCK(&ilist->mut);

   return ret;
}

//----------------------------------------------------------------------------

int dnxJobListCollect(DnxJobList * pJobList, DnxXID * pxid, DnxNewJob * pJob)
{
   iDnxJobList * ilist = (iDnxJobList *)pJobList;
   unsigned long current;
   int ret = DNX_OK;

   assert(pJobList && pxid && pJob);   // parameter validation

   current = pxid->objSlot;

   assert(current < ilist->size);
   if (current >= ilist->size)         // runtime validation requires check
      return DNX_ERR_INVALID;          // corrupt client network message

   DNX_PT_MUTEX_LOCK(&ilist->mut);

   dnxDebug(8, "dnxJobListCollect: Compare job [%lu,%lu] to job [%lu,%lu]: "
         "Head=%lu, DHead=%lu, Tail=%lu.", pxid->objSerial, pxid->objSlot,
         ilist->list[current].xid.objSerial, ilist->list[current].xid.objSlot,
         ilist->head, ilist->dhead, ilist->tail);

   // verify that the XID of this result matches the XID of the service check
   if (ilist->list[current].state == DNX_JOB_NULL
         || !dnxEqualXIDs(pxid, &ilist->list[current].xid))
      ret = DNX_ERR_NOTFOUND;          // job expired; removed by the timer
   else
   {
      // make a copy for the Collector
      memcpy(pJob, &ilist->list[current], sizeof *pJob);
      pJob->state = DNX_JOB_COMPLETE;

      // dequeue this job; make slot available for another job
      ilist->list[current].state = DNX_JOB_NULL;

      // update the job list head
      if (current == ilist->head && current != ilist->tail)
         ilist->head = (current + 1) % ilist->size;
   }

   DNX_PT_MUTEX_UNLOCK(&ilist->mut);

   return ret;
}

//----------------------------------------------------------------------------

int dnxJobListCreate(unsigned size, DnxJobList ** ppJobList)
{
   iDnxJobList * ilist;
   int ret;

   assert(ppJobList && size);

   if ((ilist = (iDnxJobList *)xmalloc(sizeof *ilist)) == 0)
      return DNX_ERR_MEMORY;
   memset(ilist, 0, sizeof *ilist);

   if ((ilist->list = (DnxNewJob *)xmalloc(sizeof *ilist->list * size)) == 0)
   {
      xfree(ilist);
      return DNX_ERR_MEMORY;
   }
   memset(ilist->list, 0, sizeof *ilist->list * size);

   ilist->size = size;

   DNX_PT_MUTEX_INIT(&ilist->mut);
   pthread_cond_init(&ilist->cond, 0);

   if ((ret = dnxTimerCreate((DnxJobList *)ilist, DNX_TIMER_SLEEP,
         &ilist->timer)) != 0)
   {
      DNX_PT_COND_DESTROY(&ilist->cond);
      DNX_PT_MUTEX_DESTROY(&ilist->mut);
      xfree(ilist->list);
      xfree(ilist);
      return ret;
   }

   *ppJobList = (DnxJobList *)ilist;

   return DNX_OK;
}

//----------------------------------------------------------------------------

void dnxJobListDestroy(DnxJobList * pJobList)
{
   iDnxJobList * ilist = (iDnxJobList *)pJobList;

   assert(pJobList);

   dnxTimerDestroy(ilist->timer);

   DNX_PT_COND_DESTROY(&ilist->cond);
   DNX_PT_MUTEX_DESTROY(&ilist->mut);

   xfree(ilist->list);
   xfree(ilist);
}

/*--------------------------------------------------------------------------
                                 UNIT TEST

   From within dnx/server, compile with GNU tools using this command line:

      gcc -DDEBUG -DDNX_JOBLIST_TEST -g -O0 -I../common dnxJobList.c \
         ../common/dnxError.c -lpthread -lgcc_s -lrt -o dnxJobListTest

  --------------------------------------------------------------------------*/

#ifdef DNX_JOBLIST_TEST

#include "utesthelp.h"
#include <time.h>

#define elemcount(x) (sizeof(x)/sizeof(*(x)))

static int verbose;

// functional stubs
IMPLEMENT_DNX_DEBUG(verbose);
IMPLEMENT_DNX_SYSLOG(verbose);

int dnxTimerCreate(DnxJobList * jl, int s, DnxTimer ** pt) { *pt = 0; return 0; }
void dnxTimerDestroy(DnxTimer * t) { }

int dnxEqualXIDs(DnxXID * pxa, DnxXID * pxb)
      { return pxa->objType == pxb->objType && pxa->objSerial == pxb->objSerial
            && pxa->objSlot == pxb->objSlot; }

int dnxMakeXID(DnxXID * x, DnxObjType t, unsigned long s, unsigned long l)
      { x->objType = t; x->objSerial = s; x->objSlot = l; return DNX_OK; }

int main(int argc, char ** argv)
{
   DnxJobList * jobs;
   DnxNodeRequest n1[101];
   DnxNewJob j1[101];
   DnxNewJob jtmp;
   DnxXID xid;
   int serial, xlsz, expcount;
   iDnxJobList * ijobs;
   time_t now;

   verbose = argc > 1;

   // create a new job list and get a concrete reference to it for testing
   CHECK_ZERO(dnxJobListCreate(100, &jobs));
   ijobs = (iDnxJobList *)jobs;

   // force entire array to non-zero values for testing
   memset(j1, 0xcc, sizeof j1);
   memset(n1, 0xdd, sizeof n1);

   // test that we CAN add 100 jobs to the 100-job list
   now = time(0);
   for (serial = 0; serial < elemcount(j1); serial++)
   {
      // configure request node
      dnxMakeXID(&n1[serial].xid, DNX_OBJ_WORKER, serial, 0);
      n1[serial].reqType      = DNX_REQ_REGISTER;
      n1[serial].jobCap       = 1;     // jobs
      n1[serial].ttl          = 5;     // seconds
      n1[serial].expires      = 5;     // seconds
      strcpy(n1[serial].address, "localhost");

      // configure job
      dnxMakeXID(&j1[serial].xid, DNX_OBJ_JOB, serial, 0);
      j1[serial].cmd          = "some command line";
      j1[serial].start_time   = now;
      j1[serial].timeout      = serial < 50? 0: 5;  // 50 expire immediately
      j1[serial].expires      = j1[serial].start_time + j1[serial].timeout;
      j1[serial].payload      = 0;     // no payload for tests
      j1[serial].pNode        = &n1[serial];

      if (serial < 100)
         CHECK_ZERO(dnxJobListAdd(jobs, &j1[serial]));
      else  // test that we CAN'T add 101 jobs
         CHECK_NONZERO(dnxJobListAdd(jobs, &j1[serial]));
   }

   // test job expiration - ensure first 50 jobs have already expired
   expcount = 0;
   do
   {
      DnxNewJob xl[10];
      xlsz = (int)elemcount(xl);
      CHECK_ZERO(dnxJobListExpire(jobs, xl, &xlsz));
      expcount += xlsz;
   } while (xlsz != 0);
   CHECK_TRUE(expcount == 50);

   // dispatch 49 of the remaining 50 jobs
   for (serial = 50; serial < elemcount(j1) - 2; serial++)
      CHECK_ZERO(dnxJobListDispatch(jobs, &jtmp));

   // ensure the dispatch head is valid and not in progress
   CHECK_TRUE(ijobs->dhead != 0);
   CHECK_TRUE(ijobs->list[ijobs->dhead].state != DNX_JOB_INPROGRESS);
   CHECK_TRUE(ijobs->list[ijobs->head].state == DNX_JOB_INPROGRESS);

   // ensure dispatch head points to last item in list
   CHECK_TRUE(ijobs->dhead == 99);

   // collect all pending jobs
   for (serial = 50; serial < elemcount(j1) - 2; serial++)
   {
      dnxMakeXID(&xid, DNX_OBJ_JOB, serial, serial);
      CHECK_ZERO(dnxJobListCollect(jobs, &xid, &jtmp));
   }

   // ensure there's one left
   CHECK_TRUE(ijobs->head == ijobs->tail);
   CHECK_TRUE(ijobs->head != 0);

   // ensure head, tail and dhead all point to the last element (99)
   CHECK_TRUE(ijobs->head == 99);
   CHECK_TRUE(ijobs->tail == 99);
   CHECK_TRUE(ijobs->dhead == 99);

   dnxJobListDestroy(jobs);

   return 0;
}

#endif   /* DNX_JOBLIST_TEST */

/*--------------------------------------------------------------------------*/