1 files changed, 130 insertions, 46 deletions

diff --git a/mysys/my_alloc.c b/mysys/my_alloc.c
index db482454e69..4d3b0604984 100644
--- a/mysys/my_alloc.c
+++ b/mysys/my_alloc.c
@@ -1,42 +1,47 @@
-/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
-   
-   This library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Library General Public
-   License as published by the Free Software Foundation; either
-   version 2 of the License, or (at your option) any later version.
-   
-   This library is distributed in the hope that it will be useful,
+/* Copyright (C) 2000 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   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
-   Library General Public License for more details.
-   
-   You should have received a copy of the GNU Library General Public
-   License along with this library; if not, write to the Free
-   Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
-   MA 02111-1307, USA */
+   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 */
 
 /* Routines to handle mallocing of results which will be freed the same time */
 
-#include <global.h>
+#include <my_global.h>
 #include <my_sys.h>
 #include <m_string.h>
+#undef EXTRA_DEBUG
+#define EXTRA_DEBUG
 
-void init_alloc_root(MEM_ROOT *mem_root, uint block_size, uint pre_alloc_size)
+void init_alloc_root(MEM_ROOT *mem_root, uint block_size,
+		     uint pre_alloc_size __attribute__((unused)))
 {
-  mem_root->free=mem_root->used=0;
-  mem_root->min_malloc=32;
-  mem_root->block_size=block_size-MALLOC_OVERHEAD-sizeof(USED_MEM)-8;
-  mem_root->error_handler=0;
+  mem_root->free= mem_root->used= mem_root->pre_alloc= 0;
+  mem_root->min_malloc= 32;
+  mem_root->block_size= block_size-MALLOC_OVERHEAD-sizeof(USED_MEM)-8;
+  mem_root->error_handler= 0;
+  mem_root->block_num= 4;			/* We shift this with >>2 */
+  mem_root->first_block_usage= 0;
+
 #if !(defined(HAVE_purify) && defined(EXTRA_DEBUG))
   if (pre_alloc_size)
   {
-    if ((mem_root->free = mem_root->pre_alloc=
+    if ((mem_root->free= mem_root->pre_alloc=
 	 (USED_MEM*) my_malloc(pre_alloc_size+ ALIGN_SIZE(sizeof(USED_MEM)),
 			       MYF(0))))
     {
-      mem_root->free->size=pre_alloc_size+ALIGN_SIZE(sizeof(USED_MEM));
-      mem_root->free->left=pre_alloc_size;
-      mem_root->free->next=0;
+      mem_root->free->size= pre_alloc_size+ALIGN_SIZE(sizeof(USED_MEM));
+      mem_root->free->left= pre_alloc_size;
+      mem_root->free->next= 0;
     }
   }
 #endif
@@ -54,29 +59,37 @@ gptr alloc_root(MEM_ROOT *mem_root,unsigned int Size)
       (*mem_root->error_handler)();
     return((gptr) 0);				/* purecov: inspected */
   }
-  next->next=mem_root->used;
-  mem_root->used=next;
+  next->next= mem_root->used;
+  next->size= Size;
+  mem_root->used= next;
   return (gptr) (((char*) next)+ALIGN_SIZE(sizeof(USED_MEM)));
 #else
-  uint get_size,max_left;
+  uint get_size, block_size;
   gptr point;
-  reg1 USED_MEM *next;
+  reg1 USED_MEM *next= 0;
   reg2 USED_MEM **prev;
 
   Size= ALIGN_SIZE(Size);
-  prev= &mem_root->free;
-  max_left=0;
-  for (next= *prev ; next && next->left < Size ; next= next->next)
+  if ((*(prev= &mem_root->free)) != NULL)
   {
-    if (next->left > max_left)
-      max_left=next->left;
-    prev= &next->next;
+    if ((*prev)->left < Size &&
+	mem_root->first_block_usage++ >= ALLOC_MAX_BLOCK_USAGE_BEFORE_DROP &&
+	(*prev)->left < ALLOC_MAX_BLOCK_TO_DROP)
+    {
+      next= *prev;
+      *prev= next->next;			/* Remove block from list */
+      next->next= mem_root->used;
+      mem_root->used= next;
+      mem_root->first_block_usage= 0;
+    }
+    for (next= *prev ; next && next->left < Size ; next= next->next)
+      prev= &next->next;
   }
   if (! next)
   {						/* Time to alloc new block */
+    block_size= mem_root->block_size * (mem_root->block_num >> 2);
     get_size= Size+ALIGN_SIZE(sizeof(USED_MEM));
-    if (max_left*4 < mem_root->block_size && get_size < mem_root->block_size)
-      get_size=mem_root->block_size;		/* Normal alloc */
+    get_size= max(get_size, block_size);
 
     if (!(next = (USED_MEM*) my_malloc(get_size,MYF(MY_WME))))
     {
@@ -84,23 +97,55 @@ gptr alloc_root(MEM_ROOT *mem_root,unsigned int Size)
 	(*mem_root->error_handler)();
       return((gptr) 0);				/* purecov: inspected */
     }
+    mem_root->block_num++;
     next->next= *prev;
     next->size= get_size;
     next->left= get_size-ALIGN_SIZE(sizeof(USED_MEM));
     *prev=next;
   }
+    
   point= (gptr) ((char*) next+ (next->size-next->left));
+  /*TODO: next part may be unneded due to mem_root->first_block_usage counter*/
   if ((next->left-= Size) < mem_root->min_malloc)
   {						/* Full block */
-    *prev=next->next;				/* Remove block from list */
-    next->next=mem_root->used;
-    mem_root->used=next;
+    *prev= next->next;				/* Remove block from list */
+    next->next= mem_root->used;
+    mem_root->used= next;
+    mem_root->first_block_usage= 0;
   }
   return(point);
 #endif
 }
 
-	/* deallocate everything used by alloc_root */
+/* Mark all data in blocks free for reusage */
+
+static inline void mark_blocks_free(MEM_ROOT* root)
+{
+  reg1 USED_MEM *next;
+  reg2 USED_MEM **last;
+
+  /* iterate through (partially) free blocks, mark them free */
+  last= &root->free;
+  for (next= root->free; next; next= *(last= &next->next))
+    next->left= next->size - ALIGN_SIZE(sizeof(USED_MEM));
+
+  /* Combine the free and the used list */
+  *last= next=root->used;
+
+  /* now go through the used blocks and mark them free */
+  for (; next; next= next->next)
+    next->left= next->size - ALIGN_SIZE(sizeof(USED_MEM));
+
+  /* Now everything is set; Indicate that nothing is used anymore */
+  root->used= 0;
+  root->first_block_usage= 0;
+}
+
+
+/*
+  Deallocate everything used by alloc_root or just move
+  used blocks to free list if called with MY_USED_TO_FREE
+*/
 
 void free_root(MEM_ROOT *root, myf MyFlags)
 {
@@ -109,18 +154,23 @@ void free_root(MEM_ROOT *root, myf MyFlags)
 
   if (!root)
     DBUG_VOID_RETURN; /* purecov: inspected */
+  if (MyFlags & MY_MARK_BLOCKS_FREE)
+  {
+    mark_blocks_free(root);
+    DBUG_VOID_RETURN;
+  }
   if (!(MyFlags & MY_KEEP_PREALLOC))
     root->pre_alloc=0;
 
-  for ( next=root->used; next ;)
+  for (next=root->used; next ;)
   {
     old=next; next= next->next ;
     if (old != root->pre_alloc)
       my_free((gptr) old,MYF(0));
   }
-  for (next= root->free ; next ; )
+  for (next=root->free ; next ;)
   {
-    old=next; next= next->next ;
+    old=next; next= next->next;
     if (old != root->pre_alloc)
       my_free((gptr) old,MYF(0));
   }
@@ -131,16 +181,50 @@ void free_root(MEM_ROOT *root, myf MyFlags)
     root->free->left=root->pre_alloc->size-ALIGN_SIZE(sizeof(USED_MEM));
     root->free->next=0;
   }
+  root->block_num= 4;
+  root->first_block_usage= 0;
   DBUG_VOID_RETURN;
 }
 
+/*
+  Find block that contains an object and set the pre_alloc to it
+*/
+
+void set_prealloc_root(MEM_ROOT *root, char *ptr)
+{
+  USED_MEM *next;
+  for (next=root->used; next ; next=next->next)
+  {
+    if ((char*) next <= ptr && (char*) next + next->size > ptr)
+    {
+      root->pre_alloc=next;
+      return;
+    }
+  }
+  for (next=root->free ; next ; next=next->next)
+  {
+    if ((char*) next <= ptr && (char*) next + next->size > ptr)
+    {
+      root->pre_alloc=next;
+      return;
+    }
+  }
+}
+
 
 char *strdup_root(MEM_ROOT *root,const char *str)
 {
-  uint len= (uint) strlen(str)+1;
+  return strmake_root(root, str, strlen(str));
+}
+
+char *strmake_root(MEM_ROOT *root,const char *str, uint len)
+{
   char *pos;
-  if ((pos=alloc_root(root,len)))
+  if ((pos=alloc_root(root,len+1)))
+  {
     memcpy(pos,str,len);
+    pos[len]=0;
+  }
   return pos;
 }