stasis-aries-wal/src/lladd/bufferManager.c

/*---
This software is copyrighted by the Regents of the University of
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each file where they apply.
                                                                                                                                  
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---*/
/*******************************
 * $Id$
 *
 * implementation of the page buffer
 * *************************************************/

#include <config.h>

#ifdef PROFILE_LATCHES_WRITE_ONLY

#define _GNU_SOURCE   
#include <stdio.h>  // Need _GNU_SOURCE for asprintf
#include <lladd/lhtable.h>

#endif

#include <lladd/common.h>
#include <latches.h>
#include <assert.h>

#include <lladd/bufferManager.h>

#include <lladd/bufferPool.h>

#include <lladd/lockManager.h>
#include <lladd/pageCache.h>
#include "pageFile.h"

#include <lladd/truncation.h>

#include <lladd/lhtable.h>

#undef loadPage
#undef releasePage
#undef Page

#ifdef LONG_TEST 
#define PIN_COUNT
#endif

#ifdef PROFILE_LATCHES_WRITE_ONLY

// These should only be defined if PROFILE_LATCHES_WRITE_ONLY is set.

#undef loadPage
#undef releasePage

pthread_mutex_t profile_load_mutex = PTHREAD_MUTEX_INITIALIZER;
struct LH_ENTRY(table) * profile_load_hash = 0;
struct LH_ENTRY(table) * profile_load_pins_hash = 0;

#endif

#ifdef PIN_COUNT
pthread_mutex_t pinCount_mutex = PTHREAD_MUTEX_INITIALIZER;
int pinCount = 0;
#endif

static struct LH_ENTRY(table) *activePages; /* page lookup */
/*static Page * activePagePtrs[MAX_BUFFER_SIZE];*/


static pthread_mutex_t loadPagePtr_mutex;

static Page * dummy_page;

static pthread_key_t lastPage;

static int bufManBufInit() {

        bufferPoolInit();

	openPageFile();


	pthread_mutex_init(&loadPagePtr_mutex, NULL);

	activePages = LH_ENTRY(create)(16);

	dummy_page = pageMalloc();
	pageFree(dummy_page, -1);
	Page *first;
	first = pageMalloc();
	pageFree(first, 0);
	LH_ENTRY(insert)(activePages, &first->id, sizeof(int), first);

	pageCacheInit(first);

	int err = pthread_key_create(&lastPage, 0);
	assert(!err);

	assert(activePages);
#ifdef PROFILE_LATCHES_WRITE_ONLY
    profile_load_hash = LH_ENTRY(create)(10);
    profile_load_pins_hash = LH_ENTRY(create)(10);
#endif
	return 0;
}

static void bufManBufDeinit() {

	DEBUG("pageCacheDeinit()");

	struct LH_ENTRY(list) iter;
	const struct LH_ENTRY(pair_t) * next;
	LH_ENTRY(openlist(activePages, &iter));

	while((next = LH_ENTRY(readlist)(&iter))) { 
	  pageWrite((Page*)next->value);
	  DEBUG("+");
	}

	LH_ENTRY(destroy)(activePages);

	pthread_mutex_destroy(&loadPagePtr_mutex);
	
	pageCacheDeinit();
	closePageFile();

	bufferPoolDeInit();
	
#ifdef PIN_COUNT
	if(pinCount != 0) { 
	  printf("WARNING:  At exit, %d pages were still pinned!\n", pinCount);
	}
#endif
	return;
}
/**
    Just close file descriptors, don't do any other clean up. (For
    testing.)
*/
void simulateBufferManagerCrash() {
  closePageFile();
#ifdef PIN_COUNT
  pinCount = 0;
#endif
}

static void bufManReleasePage (Page * p) {
  unlock(p->loadlatch);
#ifdef PIN_COUNT
  pthread_mutex_lock(&pinCount_mutex);
  pinCount --;
  pthread_mutex_unlock(&pinCount_mutex);
#endif

}

static Page * getPage(int pageid, int locktype) {
  Page * ret;
  int spin  = 0;

  pthread_mutex_lock(&loadPagePtr_mutex);
  ret = LH_ENTRY(find)(activePages, &pageid, sizeof(int));

  if(ret) {
#ifdef PROFILE_LATCHES_WRITE_ONLY
    // "holder" will contain a \n delimited list of the sites that
    // called loadPage() on the pinned page since the last time it was
    // completely unpinned.  One such site is responsible for the
    // leak.
    
    char * holder = LH_ENTRY(find)(profile_load_hash, &ret, sizeof(void*));
    int * pins = LH_ENTRY(find)(profile_load_pins_hash, &ret, sizeof(void*));
    char * holderD =0;
    int pinsD = 0;
    if(holder) {
      holderD = strdup(holder);
      pinsD = *pins; 
    }
#endif
    if(locktype == RW) {
      writelock(ret->loadlatch, 217);
    } else {
      readlock(ret->loadlatch, 217);
    }
#ifdef PROFILE_LATCHES_WRITE_ONLY
    if(holderD) 
      free(holderD);
#endif
  }

  while (ret && (ret->id != pageid)) {
    unlock(ret->loadlatch);
    pthread_mutex_unlock(&loadPagePtr_mutex);
    sched_yield();
    pthread_mutex_lock(&loadPagePtr_mutex);
    ret = LH_ENTRY(find)(activePages, &pageid, sizeof(int));

    if(ret) {
#ifdef PROFILE_LATCHES_WRITE_ONLY
      // "holder" will contain a \n delimited list of the sites that
      // called loadPage() on the pinned page since the last time it was
      // completely unpinned.  One such site is responsible for the
      // leak.
      
      char * holder = LH_ENTRY(find)(profile_load_hash, &ret, sizeof(void*));
      int * pins = LH_ENTRY(find)(profile_load_pins_hash, &ret, sizeof(void*));
      
      char * holderD = 0;
      int pinsD = 0;
      if(holder) { 
	holderD = strdup(holder);
	pinsD = *pins;
      }
#endif
      if(locktype == RW) {
	writelock(ret->loadlatch, 217);
      } else {
	readlock(ret->loadlatch, 217);
      }
#ifdef PROFILE_LATCHES_WRITE_ONLY
      if(holderD)
	free(holderD);
#endif
    }
    spin++;
    if(spin > 10000 && !(spin % 10000)) {
      printf("GetPage is stuck!");
    }
  } 

  if(ret) { 
    cacheHitOnPage(ret);
    assert(ret->id == pageid);
    pthread_mutex_unlock(&loadPagePtr_mutex);
  } else {

    /* If ret is null, then we know that:

       a) there is no cache entry for pageid
       b) this is the only thread that has gotten this far,
          and that will try to add an entry for pageid
       c) the most recent version of this page has been 
          written to the OS's file cache.                  */
    int oldid = -1;

    if( cache_state == FULL ) {

      /* Select an item from cache, and remove it atomicly. (So it's
	 only reclaimed once) */

      ret = cacheStalePage();
      cacheRemovePage(ret);

      oldid = ret->id;
    
      assert(oldid != pageid);

    } else {

      ret = pageMalloc();
      ret->id = -1;
      ret->inCache = 0;
    }

    // If you leak a page, and it eventually gets evicted, and reused, the system deadlocks here.
#ifdef PROFILE_LATCHES_WRITE_ONLY
    // "holder" will contain a \n delimited list of the sites that
    // called loadPage() on the pinned page since the last time it was
    // completely unpinned.  One such site is responsible for the
    // leak.

    char * holder = LH_ENTRY(find)(profile_load_hash, &ret, sizeof(void*));
    int * pins = LH_ENTRY(find)(profile_load_pins_hash, &ret, sizeof(void*));

    char * holderD = 0;
    int pinsD = 0;
    if(holder) { 
      holderD = strdup(holder);
      pinsD = *pins;
    }
    
#endif

    writelock(ret->loadlatch, 217); 
#ifdef PROFILE_LATCHES_WRITE_ONLY
    if(holderD)
      free(holderD);
#endif

    /* Inserting this into the cache before releasing the mutex
       ensures that constraint (b) above holds. */
    LH_ENTRY(insert)(activePages, &pageid, sizeof(int), ret);
    pthread_mutex_unlock(&loadPagePtr_mutex); 

    /* Could writelock(ret) go here? */

    assert(ret != dummy_page);
    if(ret->id != -1) { 
      pageWrite(ret);
    }

    pageFree(ret, pageid);

    pageRead(ret);

    writeunlock(ret->loadlatch);
 
    pthread_mutex_lock(&loadPagePtr_mutex);

    LH_ENTRY(remove)(activePages, &(oldid), sizeof(int));

    /* @todo Put off putting this back into cache until we're done with
       it. -- This could cause the cache to empty out if the ratio of
       threads to buffer slots is above ~ 1/3, but it decreases the
       liklihood of thrashing. */
    cacheInsertPage(ret);

    pthread_mutex_unlock(&loadPagePtr_mutex);
#ifdef PROFILE_LATCHES_WRITE_ONLY
    // "holder" will contain a \n delimited list of the sites that
    // called loadPage() on the pinned page since the last time it was
    // completely unpinned.  One such site is responsible for the
    // leak.
    
    holder = LH_ENTRY(find)(profile_load_hash, &ret, sizeof(void*));
    pins = LH_ENTRY(find)(profile_load_pins_hash, &ret, sizeof(void*));
    
    if(holder) {
      holderD = strdup(holder);
      pinsD = *pins;
    }
#endif
    if(locktype == RW) {
      writelock(ret->loadlatch, 217);
    } else {
      readlock(ret->loadlatch, 217);
    }
#ifdef PROFILE_LATCHES_WRITE_ONLY
    if(holderD)
      free(holderD);
#endif
    if(ret->id != pageid) {
      unlock(ret->loadlatch);
      printf("pageCache.c: Thrashing detected.  Strongly consider increasing LLADD's buffer pool size!\n"); 
      fflush(NULL);
      return getPage(pageid, locktype);
    }

  }
  return ret;
}

#ifdef PROFILE_LATCHES_WRITE_ONLY

compensated_function Page * __profile_loadPage(int xid, int pageid, char * file, int line) { 

  Page * ret = loadPage(xid, pageid);


  pthread_mutex_lock(&profile_load_mutex);

  char * holder = LH_ENTRY(find)(profile_load_hash, &ret, sizeof(void*));
  int * pins = LH_ENTRY(find)(profile_load_pins_hash, &ret, sizeof(void*));

  if(!pins) { 
    pins = malloc(sizeof(int));
    *pins = 0;
    LH_ENTRY(insert)(profile_load_pins_hash, &ret, sizeof(void*), pins);
  }

  if(*pins) { 
    assert(holder);
    char * newHolder;
    asprintf(&newHolder, "%s\n%s:%d", holder, file, line);
    free(holder);
    holder = newHolder;
  } else { 
    assert(!holder);
    asprintf(&holder, "%s:%d", file, line);
  }
  (*pins)++;
  LH_ENTRY(insert)(profile_load_hash, &ret, sizeof(void*), holder);
  pthread_mutex_unlock(&profile_load_mutex);

  return ret;

}


compensated_function void  __profile_releasePage(Page * p) { 
  pthread_mutex_lock(&profile_load_mutex);

  //  int pageid = p->id;
  int * pins = LH_ENTRY(find)(profile_load_pins_hash, &p, sizeof(void*));

  assert(pins);

  if(*pins == 1) {
    
    char * holder = LH_ENTRY(remove)(profile_load_hash, &p, sizeof(void*));
    assert(holder);
    free(holder); 

  }

  (*pins)--;

  pthread_mutex_unlock(&profile_load_mutex);

  releasePage(p);


}

#endif

static compensated_function Page *bufManLoadPage(int xid, int pageid) {

  try_ret(NULL) {
    if(globalLockManager.readLockPage) { globalLockManager.readLockPage(xid, pageid); }
  } end_ret(NULL);


  Page * ret = pthread_getspecific(lastPage);

  if(ret && ret->id == pageid) { 
    pthread_mutex_lock(&loadPagePtr_mutex);
    readlock(ret->loadlatch, 1);
    if(ret->id != pageid) { 
      unlock(ret->loadlatch);
      ret = 0;
    } else { 
      cacheHitOnPage(ret);
      pthread_mutex_unlock(&loadPagePtr_mutex);
    }
  } else { 
    ret = 0;
  }
  if(!ret) { 
    ret = getPage(pageid, RO);
    pthread_setspecific(lastPage, ret);
  }

#ifdef PIN_COUNT
  pthread_mutex_lock(&pinCount_mutex);
  pinCount ++;
  pthread_mutex_unlock(&pinCount_mutex);
#endif

  return ret;
}

Page * (*loadPage)(int xid, int pageid) = 0;
void   (*releasePage)(Page * p) = 0;
void (*writeBackPage)(Page * p) = 0;
void (*forcePages)() = 0;

void   (*bufDeinit)()  = 0;
int bufInit(int type) { 
  static int lastType = 0;
  if(type == BUFFER_MANAGER_REOPEN) { 
    type = lastType;
  } 
  lastType = type;
  if(type == BUFFER_MANAGER_HASH) { 
    releasePage = bufManReleasePage;
    loadPage = bufManLoadPage;
    writeBackPage = pageWrite;
    forcePages = forcePageFile;
    bufDeinit = bufManBufDeinit; 
    bufManBufInit();
    return 0;
  } else { 
    // XXX error handling
    abort();
  } 
}