sys/dev/raidframe/rf_revent.c

   1 /*      $NetBSD: rf_revent.c,v 1.24 2006/11/16 01:33:23 christos Exp $  */
   2 /*
   3  * Copyright (c) 1995 Carnegie-Mellon University.
   4  * All rights reserved.
   5  *
   6  * Author:
   7  *
   8  * Permission to use, copy, modify and distribute this software and
   9  * its documentation is hereby granted, provided that both the copyright
  10  * notice and this permission notice appear in all copies of the
  11  * software, derivative works or modified versions, and any portions
  12  * thereof, and that both notices appear in supporting documentation.
  13  *
  14  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  15  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
  16  * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  17  *
  18  * Carnegie Mellon requests users of this software to return to
  19  *
  20  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  21  *  School of Computer Science
  22  *  Carnegie Mellon University
  23  *  Pittsburgh PA 15213-3890
  24  *
  25  * any improvements or extensions that they make and grant Carnegie the
  26  * rights to redistribute these changes.
  27  */
  28 /*
  29  * revent.c -- reconstruction event handling code
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __KERNEL_RCSID(0, "$NetBSD: rf_revent.c,v 1.24 2006/11/16 01:33:23 christos Exp $");
  34
  35 #include <sys/errno.h>
  36
  37 #include "rf_raid.h"
  38 #include "rf_revent.h"
  39 #include "rf_etimer.h"
  40 #include "rf_general.h"
  41 #include "rf_desc.h"
  42 #include "rf_shutdown.h"
  43
  44 #define RF_MAX_FREE_REVENT 128
  45 #define RF_MIN_FREE_REVENT  32
  46 #define RF_EVENTQ_WAIT 5000
  47
  48 #include <sys/proc.h>
  49 #include <sys/kernel.h>
  50
  51 static void rf_ShutdownReconEvent(void *);
  52
  53 static RF_ReconEvent_t *
  54 GetReconEventDesc(RF_RowCol_t col, void *arg, RF_Revent_t type);
  55
  56 static void rf_ShutdownReconEvent(void *ignored)
  57 {
  58         pool_destroy(&rf_pools.revent);
  59 }
  60
  61 int
  62 rf_ConfigureReconEvent(RF_ShutdownList_t **listp)
  63 {
  64
  65         rf_pool_init(&rf_pools.revent, sizeof(RF_ReconEvent_t),
  66                      "rf_revent_pl", RF_MIN_FREE_REVENT, RF_MAX_FREE_REVENT);
  67         rf_ShutdownCreate(listp, rf_ShutdownReconEvent, NULL);
  68
  69         return (0);
  70 }
  71
  72 /* returns the next reconstruction event, blocking the calling thread
  73  * until one becomes available.  will now return null if it is blocked
  74  * or will return an event if it is not */
  75
  76 RF_ReconEvent_t *
  77 rf_GetNextReconEvent(RF_RaidReconDesc_t *reconDesc)
  78 {
  79         RF_Raid_t *raidPtr = reconDesc->raidPtr;
  80         RF_ReconCtrl_t *rctrl = raidPtr->reconControl;
  81         RF_ReconEvent_t *event;
  82         int stall_count;
  83
  84         RF_LOCK_MUTEX(rctrl->eq_mutex);
  85         /* q null and count==0 must be equivalent conditions */
  86         RF_ASSERT((rctrl->eventQueue == NULL) == (rctrl->eq_count == 0));
  87
  88         /* mpsleep timeout value: secs = timo_val/hz.  'ticks' here is
  89            defined as cycle-counter ticks, not softclock ticks */
  90
  91 #define MAX_RECON_EXEC_USECS (100 * 1000)  /* 100 ms */
  92 #define RECON_DELAY_MS 25
  93 #define RECON_TIMO     ((RECON_DELAY_MS * hz) / 1000)
  94
  95         /* we are not pre-emptible in the kernel, but we don't want to run
  96          * forever.  If we run w/o blocking for more than MAX_RECON_EXEC_TICKS
  97          * ticks of the cycle counter, delay for RECON_DELAY before
  98          * continuing. this may murder us with context switches, so we may
  99          * need to increase both the MAX...TICKS and the RECON_DELAY_MS. */
 100         if (reconDesc->reconExecTimerRunning) {
 101                 int     status;
 102
 103                 RF_ETIMER_STOP(reconDesc->recon_exec_timer);
 104                 RF_ETIMER_EVAL(reconDesc->recon_exec_timer);
 105                 reconDesc->reconExecTicks +=
 106                         RF_ETIMER_VAL_US(reconDesc->recon_exec_timer);
 107                 if (reconDesc->reconExecTicks > reconDesc->maxReconExecTicks)
 108                         reconDesc->maxReconExecTicks =
 109                                 reconDesc->reconExecTicks;
 110                 if (reconDesc->reconExecTicks >= MAX_RECON_EXEC_USECS) {
 111                         /* we've been running too long.  delay for
 112                          * RECON_DELAY_MS */
 113 #if RF_RECON_STATS > 0
 114                         reconDesc->numReconExecDelays++;
 115 #endif                          /* RF_RECON_STATS > 0 */
 116
 117                         status = ltsleep(&reconDesc->reconExecTicks, PRIBIO,
 118                                          "recon delay", RECON_TIMO,
 119                                          &rctrl->eq_mutex);
 120                         RF_ASSERT(status == EWOULDBLOCK);
 121                         reconDesc->reconExecTicks = 0;
 122                 }
 123         }
 124
 125         stall_count = 0;
 126         while (!rctrl->eventQueue) {
 127 #if RF_RECON_STATS > 0
 128                 reconDesc->numReconEventWaits++;
 129 #endif                          /* RF_RECON_STATS > 0 */
 130
 131                 ltsleep(&(rctrl)->eventQueue, PRIBIO,  "raidframe eventq",
 132                         RF_EVENTQ_WAIT, &((rctrl)->eq_mutex));
 133
 134                 stall_count++;
 135
 136                 if ((stall_count > 10) &&
 137                     rctrl->headSepCBList) {
 138                         /* There is work to do on the callback list, and
 139                            we've waited long enough... */
 140                         rf_WakeupHeadSepCBWaiters(raidPtr);
 141                         stall_count = 0;
 142                 }
 143                 reconDesc->reconExecTicks = 0;  /* we've just waited */
 144         }
 145
 146         reconDesc->reconExecTimerRunning = 1;
 147         if (RF_ETIMER_VAL_US(reconDesc->recon_exec_timer)!=0) {
 148                 /* it moved!!  reset the timer. */
 149                 RF_ETIMER_START(reconDesc->recon_exec_timer);
 150         }
 151         event = rctrl->eventQueue;
 152         rctrl->eventQueue = event->next;
 153         event->next = NULL;
 154         rctrl->eq_count--;
 155
 156         /* q null and count==0 must be equivalent conditions */
 157         RF_ASSERT((rctrl->eventQueue == NULL) == (rctrl->eq_count == 0));
 158         RF_UNLOCK_MUTEX(rctrl->eq_mutex);
 159         return (event);
 160 }
 161 /* enqueues a reconstruction event on the indicated queue */
 162 void
 163 rf_CauseReconEvent(RF_Raid_t *raidPtr, RF_RowCol_t col, void *arg,
 164                    RF_Revent_t type)
 165 {
 166         RF_ReconCtrl_t *rctrl = raidPtr->reconControl;
 167         RF_ReconEvent_t *event = GetReconEventDesc(col, arg, type);
 168
 169         if (type == RF_REVENT_BUFCLEAR) {
 170                 RF_ASSERT(col != rctrl->fcol);
 171         }
 172         RF_ASSERT(col >= 0 && col <= raidPtr->numCol);
 173         RF_LOCK_MUTEX(rctrl->eq_mutex);
 174         /* q null and count==0 must be equivalent conditions */
 175         RF_ASSERT((rctrl->eventQueue == NULL) == (rctrl->eq_count == 0));
 176         event->next = rctrl->eventQueue;
 177         rctrl->eventQueue = event;
 178         rctrl->eq_count++;
 179         RF_UNLOCK_MUTEX(rctrl->eq_mutex);
 180
 181         wakeup(&(rctrl)->eventQueue);
 182 }
 183 /* allocates and initializes a recon event descriptor */
 184 static RF_ReconEvent_t *
 185 GetReconEventDesc(RF_RowCol_t col, void *arg, RF_Revent_t type)
 186 {
 187         RF_ReconEvent_t *t;
 188
 189         t = pool_get(&rf_pools.revent, PR_WAITOK);
 190         t->col = col;
 191         t->arg = arg;
 192         t->type = type;
 193         t->next = NULL;
 194         return (t);
 195 }
 196
 197 /*
 198   rf_DrainReconEventQueue() -- used in the event of a reconstruction
 199   problem, this function simply drains all pending events from the
 200   reconstruct event queue.
 201  */
 202
 203 void
 204 rf_DrainReconEventQueue(RF_RaidReconDesc_t *reconDesc)
 205 {
 206         RF_ReconCtrl_t *rctrl = reconDesc->raidPtr->reconControl;
 207         RF_ReconEvent_t *event;
 208
 209         RF_LOCK_MUTEX(rctrl->eq_mutex);
 210         while (rctrl->eventQueue!=NULL) {
 211
 212                 event = rctrl->eventQueue;
 213                 rctrl->eventQueue = event->next;
 214                 event->next = NULL;
 215                 rctrl->eq_count--;
 216                 /* dump it */
 217                 rf_FreeReconEventDesc(event);
 218         }
 219         RF_UNLOCK_MUTEX(rctrl->eq_mutex);
 220 }
 221
 222 void
 223 rf_FreeReconEventDesc(RF_ReconEvent_t *event)
 224 {
 225         pool_put(&rf_pools.revent, event);
 226 }