Add a mutex to mem6.c to make it threadsafe. (CVS 5468)

FossilOrigin-Name: 9b97ce60c63c8b8afa43496a97917afd5fc26c71

manifest

@@ -1,5 +1,5 @@
-C Add\smem6.c,\sa\snew\sallocator.\sMore\sto\scome.\s(CVS\s5467)
-D 2008-07-24T08:20:40
+C Add\sa\smutex\sto\smem6.c\sto\smake\sit\sthreadsafe.\s(CVS\s5468)
+D 2008-07-24T10:11:28
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 77ff156061bb870aa0a8b3d545c670d08070f7e6
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -123,7 +123,7 @@ F src/mem2.c 1e14a86d12dff279427cc52bb41ce5d80f138137
 F src/mem3.c c73e935d0b900abc51d5fa45f880937b062f4a9f
 F src/mem4.c 6703adb1717b26d9d70a1c2586b4b7b7ffee7909
 F src/mem5.c 0b0ba1c2a02d86eb812dea6debacee841e3856f7
-F src/mem6.c c80dcbf6dbfe225282abcd9de2387dfca2c8515e
+F src/mem6.c af63943a8311ad87d12d9b4d4908f87b3f956773
 F src/mutex.c a485a0eac8ee2cd95f66e565b4c6696c18db968f
 F src/mutex.h e52ffa1dfc6a6077e8b1823d2c2b7dfcbcf85594
 F src/mutex_os2.c 9c5637aa4c307c552566d0f0b3bd206245b54a97
@@ -436,7 +436,7 @@ F test/pager2.test c025f91b75fe65e85febda64d9416428b8a5cab5
 F test/pager3.test 2323bf27fd5bd887b580247e5bce500ceee994b4
 F test/pageropt.test 6df72c441db0a037b7ec6990d16311c24fbea77b
 F test/pagesize.test e0a8b3fe80f8b8e808d94a00734c7a18c76c407e
-F test/permutations.test 3ed44783c79005f82585e68955b393521cd12d9e
+F test/permutations.test d90e744f64f05e9cc99ebbb4ae588301f1aeaafc
 F test/pragma.test 2c675ed9a288094ed62bf55b35fbc749e25670fb
 F test/pragma2.test 5364893491b9231dd170e3459bfc2e2342658b47
 F test/printf.test 262a5acd3158f788e9bdf7f18d718f3af32ff6ef
@@ -612,7 +612,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 1dbced29de5f59ba2ebf877edcadf171540374d1
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 4a9dd5e782a363e93d4705fa3671bc6cf0bb5a33
-R 8b283cbfe876ed053eb7874d7f342505
+P 192bc192185a7b475ef9331e2a4a0dc68083ec03
+R 5534db543abd237cf60349e1495c018f
 U danielk1977
-Z 8afc40bb2e219ef5496de2d6671efc02
+Z 781d9ebe3b9b2c802e3c883b54338895

manifest.uuid

@@ -1 +1 @@
-192bc192185a7b475ef9331e2a4a0dc68083ec03
+9b97ce60c63c8b8afa43496a97917afd5fc26c71

src/mem6.c

@@ -10,7 +10,7 @@
 **
 *************************************************************************
 **
-** $Id: mem6.c,v 1.1 2008/07/24 08:20:40 danielk1977 Exp $
+** $Id: mem6.c,v 1.2 2008/07/24 10:11:28 danielk1977 Exp $
 */
 
 #ifdef SQLITE_ENABLE_MEMSYS6
@@ -281,10 +281,21 @@ struct Mem6Global {
   int nChunkSize;                 /* Size of each chunk, in bytes. */
   int nMinAlloc;                  /* Minimum allowed allocation size */
 
+  sqlite3_mutex *mutex;
+
   /* This data structure will be fixed... */
   Mem6Chunk *pChunk;              /* Singly linked list of all memory chunks */
 } mem6;
 
+
+static void mem6Enter(void){
+  sqlite3_mutex_enter(mem6.mutex);
+}
+
+static void mem6Leave(void){
+  sqlite3_mutex_leave(mem6.mutex);
+}
+
 /*
 ** The argument is a pointer that may or may not have been allocated from
 ** one of the Mem6Chunk objects managed within mem6. If it is, return
@@ -309,36 +320,47 @@ static void freeChunk(Mem6Chunk *pChunk){
 
 static void *memsys6Malloc(int nByte){
   Mem6Chunk *pChunk;
-  void *p;
+  void *p = 0;
+
+  mem6Enter();
   if( nByte>=mem6.nChunkSize/3 ){
-    return mem6.parent.xMalloc(nByte);
-  }
-  for(pChunk=mem6.pChunk; pChunk; pChunk=pChunk->pNext){
-    p = chunkMalloc(pChunk, nByte);
-    if( p ){
-      return p;
+    p = mem6.parent.xMalloc(nByte);
+  }else{
+    for(pChunk=mem6.pChunk; !p && pChunk; pChunk=pChunk->pNext){
+      p = chunkMalloc(pChunk, nByte);
+    }
+  
+    if( !p ){
+      p = mem6.parent.xMalloc(mem6.nChunkSize);
+      if( p ){
+        pChunk = chunkInit((u8 *)p, mem6.nChunkSize, mem6.nMinAlloc);
+        pChunk->pNext = mem6.pChunk;
+        mem6.pChunk = pChunk;
+        p = chunkMalloc(pChunk, nByte);
+        assert(p);
+      }
     }
   }
-
-  p = mem6.parent.xMalloc(mem6.nChunkSize);
-  if( p ){
-    pChunk = chunkInit((u8 *)p, mem6.nChunkSize, mem6.nMinAlloc);
-    pChunk->pNext = mem6.pChunk;
-    mem6.pChunk = pChunk;
-    p = chunkMalloc(pChunk, nByte);
-    assert(p);
-  }
+  mem6Leave();
 
   return p;
 }
 
 static int memsys6Size(void *p){
-  Mem6Chunk *pChunk = findChunk(p);
-  return (pChunk ? chunkSize(pChunk, p) : mem6.parent.xSize(p));
+  Mem6Chunk *pChunk;
+  int iSize;
+  mem6Enter();
+  pChunk = findChunk(p);
+  iSize = (pChunk ? chunkSize(pChunk, p) : mem6.parent.xSize(p));
+  mem6Leave();
+  return iSize;
 }
 
 static void memsys6Free(void *p){
-  Mem6Chunk *pChunk = findChunk(p);
+  Mem6Chunk *pChunk;
+
+  mem6Enter();
+  pChunk = findChunk(p);
   if( pChunk ){
     chunkFree(pChunk, p);
     if( chunkIsEmpty(pChunk) ){
@@ -347,22 +369,22 @@ static void memsys6Free(void *p){
   }else{
     mem6.parent.xFree(p);
   }
+  mem6Leave();
 }
 
 static void *memsys6Realloc(void *p, int nByte){
-  Mem6Chunk *pChunk = findChunk(p);
   void *p2;
 
-  if( !pChunk ){
-    return mem6.parent.xRealloc(p, nByte);
+  if( p && nByte<=memsys6Size(p) ){
+    p2 = p;
+  }else{
+    p2 = memsys6Malloc(nByte);
+    if( p && p2 ){
+      memcpy(p2, p, memsys6Size(p));
+      memsys6Free(p);
+    }
   }
 
-  p2 = memsys6Malloc(nByte);
-  if( p2 ){
-    assert( memsys6Size(p)<nByte );
-    memcpy(p2, p, memsys6Size(p));
-    memsys6Free(p);
-  }
   return p2;
 }
 
@@ -374,13 +396,24 @@ static int memsys6Roundup(int n){
 }
 
 static int memsys6Init(void *pCtx){
+  u8 bMemstat = sqlite3Config.bMemstat;
   mem6.parent = *sqlite3MemGetDefault();
   mem6.nChunkSize = (1<<16);
   mem6.nMinAlloc = 16;
   mem6.pChunk = 0;
 
+  if( !bMemstat ){
+    mem6.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+  }
+
   /* Initialize the parent allocator. */
+#ifdef SQLITE_MEMDEBUG
+  sqlite3Config.bMemstat = 1;
+#endif
   mem6.parent.xInit(mem6.parent.pAppData);
+#ifdef SQLITE_MEMDEBUG
+  sqlite3Config.bMemstat = bMemstat;
+#endif
 
   return SQLITE_OK;
 }

test/permutations.test

@@ -9,7 +9,7 @@
 #
 #***********************************************************************
 #
-# $Id: permutations.test,v 1.14 2008/07/24 08:20:40 danielk1977 Exp $
+# $Id: permutations.test,v 1.15 2008/07/24 10:11:29 danielk1977 Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -439,26 +439,24 @@ ifcapable threadsafe {
   }
 }
 
-  run_tests "memsys6" -description {
-    Run tests using the allocator in mem6.c.
-  } -include {
-    select1.test 
-  } -initialize {
-    catch {db close}
-    sqlite3_reset_auto_extension
-    sqlite3_shutdown
-    sqlite3_config_chunkalloc
-    install_malloc_faultsim 1 
-    sqlite3_initialize
-    autoinstall_test_functions
-  } -shutdown {
-    catch {db close}
-    sqlite3_reset_auto_extension
-    sqlite3_shutdown
-    sqlite3_config_heap 0 0
-    install_malloc_faultsim 1 
-    sqlite3_initialize
-  }
+run_tests "memsys6" -description {
+  Run tests using the allocator in mem6.c.
+} -initialize {
+  catch {db close}
+  sqlite3_reset_auto_extension
+  sqlite3_shutdown
+  sqlite3_config_chunkalloc
+  install_malloc_faultsim 1 
+  sqlite3_initialize
+  autoinstall_test_functions
+} -shutdown {
+  catch {db close}
+  sqlite3_reset_auto_extension
+  sqlite3_shutdown
+  sqlite3_config_heap 0 0
+  install_malloc_faultsim 1 
+  sqlite3_initialize
+}
 
 # run_tests "crash_safe_append" -description {
 #   Run crash.test with persistent journals on a SAFE_APPEND file-system.