/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. 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 as published by the Free Software Foundation; version 2 of the License. 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ /* Routines to handle mallocing of results which will be freed the same time */ #include #include #include #include "mysys_err.h" static inline my_bool is_mem_available(MEM_ROOT *mem_root, size_t size); /* For instrumented code: don't preallocate memory in alloc_root(). This gives a lot more memory chunks, each with a red-zone around them. */ #if !defined(HAVE_VALGRIND) && !defined(HAVE_ASAN) #define PREALLOCATE_MEMORY_CHUNKS #endif /* Initialize memory root SYNOPSIS init_alloc_root() mem_root - memory root to initialize block_size - size of chunks (blocks) used for memory allocation (It is external size of chunk i.e. it should include memory required for internal structures, thus it should be no less than ALLOC_ROOT_MIN_BLOCK_SIZE) pre_alloc_size - if non-0, then size of block that should be pre-allocated during memory root initialization. DESCRIPTION This function prepares memory root for further use, sets initial size of chunk for memory allocation and pre-allocates first block if specified. Altough error can happen during execution of this function if pre_alloc_size is non-0 it won't be reported. Instead it will be reported as error in first alloc_root() on this memory root. */ void init_alloc_root(PSI_memory_key key, MEM_ROOT *mem_root, size_t block_size, size_t pre_alloc_size MY_ATTRIBUTE((unused))) { DBUG_ENTER("init_alloc_root"); DBUG_PRINT("enter",("root: 0x%lx", (long) mem_root)); mem_root->free= mem_root->used= mem_root->pre_alloc= 0; mem_root->min_malloc= 32; mem_root->block_size= block_size - ALLOC_ROOT_MIN_BLOCK_SIZE; mem_root->error_handler= 0; mem_root->block_num= 4; /* We shift this with >>2 */ mem_root->first_block_usage= 0; mem_root->m_psi_key= key; mem_root->max_capacity= 0; mem_root->allocated_size= 0; mem_root->error_for_capacity_exceeded= FALSE; #if defined(PREALLOCATE_MEMORY_CHUNKS) if (pre_alloc_size) { if ((mem_root->free= mem_root->pre_alloc= (USED_MEM*) my_malloc(key, pre_alloc_size+ ALIGN_SIZE(sizeof(USED_MEM)), MYF(0)))) { mem_root->free->size= (uint)(pre_alloc_size+ALIGN_SIZE(sizeof(USED_MEM))); mem_root->free->left= (uint)pre_alloc_size; mem_root->free->next= 0; mem_root->allocated_size+= pre_alloc_size+ ALIGN_SIZE(sizeof(USED_MEM)); } } #endif DBUG_VOID_RETURN; } /** This is a no-op unless the build is debug or for Valgrind. */ #define TRASH_MEM(X) TRASH(((char*)(X) + ((X)->size-(X)->left)), (X)->left) /* SYNOPSIS reset_root_defaults() mem_root memory root to change defaults of block_size new value of block size. Must be greater or equal than ALLOC_ROOT_MIN_BLOCK_SIZE (this value is about 68 bytes and depends on platform and compilation flags) pre_alloc_size new size of preallocated block. If not zero, must be equal to or greater than block size, otherwise means 'no prealloc'. DESCRIPTION Function aligns and assigns new value to block size; then it tries to reuse one of existing blocks as prealloc block, or malloc new one of requested size. If no blocks can be reused, all unused blocks are freed before allocation. */ void reset_root_defaults(MEM_ROOT *mem_root, size_t block_size, size_t pre_alloc_size MY_ATTRIBUTE((unused))) { DBUG_ASSERT(alloc_root_inited(mem_root)); mem_root->block_size= block_size - ALLOC_ROOT_MIN_BLOCK_SIZE; #if defined(PREALLOCATE_MEMORY_CHUNKS) if (pre_alloc_size) { size_t size= pre_alloc_size + ALIGN_SIZE(sizeof(USED_MEM)); if (!mem_root->pre_alloc || mem_root->pre_alloc->size != size) { USED_MEM *mem, **prev= &mem_root->free; /* Free unused blocks, so that consequent calls to reset_root_defaults won't eat away memory. */ while (*prev) { mem= *prev; if (mem->size == (uint)size) { /* We found a suitable block, no need to do anything else */ mem_root->pre_alloc= mem; return; } if (mem->left + ALIGN_SIZE(sizeof(USED_MEM)) == mem->size) { /* remove block from the list and free it */ *prev= mem->next; { mem->left= mem->size; mem_root->allocated_size-= mem->size; TRASH_MEM(mem); my_free(mem); } } else prev= &mem->next; } /* Allocate new prealloc block and add it to the end of free list */ if (is_mem_available(mem_root, size) && (mem= (USED_MEM *) my_malloc(mem_root->m_psi_key, size, MYF(0)))) { mem->size= (uint)size; mem->left= (uint)pre_alloc_size; mem->next= *prev; *prev= mem_root->pre_alloc= mem; mem_root->allocated_size+= size; } else { mem_root->pre_alloc= 0; } } } else #endif mem_root->pre_alloc= 0; } /** Function allocates the requested memory in the mem_root specified. If max_capacity is defined for the mem_root, it only allocates if the requested size can be allocated without exceeding the limit. However, when error_for_capacity_exceeded is set, an error is flagged (see set_error_reporting), but allocation is still performed. @param mem_root memory root to allocate memory from @length size to be allocated @retval void * Pointer to the memory thats been allocated @retval NULL Memory is not available. */ void *alloc_root(MEM_ROOT *mem_root, size_t length) { #if !defined(PREALLOCATE_MEMORY_CHUNKS) USED_MEM *next; DBUG_ENTER("alloc_root"); DBUG_PRINT("enter",("root: 0x%lx", (long) mem_root)); DBUG_ASSERT(alloc_root_inited(mem_root)); DBUG_EXECUTE_IF("simulate_out_of_memory", { if (mem_root->error_handler) (*mem_root->error_handler)(); DBUG_SET("-d,simulate_out_of_memory"); DBUG_RETURN((void*) 0); /* purecov: inspected */ }); length+=ALIGN_SIZE(sizeof(USED_MEM)); if (!is_mem_available(mem_root, length)) { if (mem_root->error_for_capacity_exceeded) my_error(EE_CAPACITY_EXCEEDED, MYF(0), (ulonglong) mem_root->max_capacity); else DBUG_RETURN(NULL); } if (!(next = (USED_MEM*) my_malloc(mem_root->m_psi_key, length,MYF(MY_WME | ME_FATALERROR)))) { if (mem_root->error_handler) (*mem_root->error_handler)(); DBUG_RETURN((uchar*) 0); /* purecov: inspected */ } mem_root->allocated_size+= length; next->next= mem_root->used; next->size= (uint)length; next->left= (uint)(length - ALIGN_SIZE(sizeof(USED_MEM))); mem_root->used= next; DBUG_PRINT("exit",("ptr: 0x%lx", (long) (((char*) next)+ ALIGN_SIZE(sizeof(USED_MEM))))); DBUG_RETURN((uchar*) (((char*) next)+ALIGN_SIZE(sizeof(USED_MEM)))); #else size_t get_size, block_size; uchar* point; USED_MEM *next= 0; USED_MEM **prev; DBUG_ENTER("alloc_root"); DBUG_PRINT("enter",("root: 0x%lx", (long) mem_root)); DBUG_ASSERT(alloc_root_inited(mem_root)); DBUG_EXECUTE_IF("simulate_out_of_memory", { /* Avoid reusing an already allocated block */ if (mem_root->error_handler) (*mem_root->error_handler)(); DBUG_SET("-d,simulate_out_of_memory"); DBUG_RETURN((void*) 0); /* purecov: inspected */ }); length= ALIGN_SIZE(length); if ((*(prev= &mem_root->free)) != NULL) { if ((*prev)->left < length && 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 < length ; 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= length+ALIGN_SIZE(sizeof(USED_MEM)); get_size= MY_MAX(get_size, block_size); if (!is_mem_available(mem_root, get_size)) { if (mem_root->error_for_capacity_exceeded) my_error(EE_CAPACITY_EXCEEDED, MYF(0), (ulonglong) mem_root->max_capacity); else DBUG_RETURN(NULL); } if (!(next = (USED_MEM*) my_malloc(mem_root->m_psi_key, get_size,MYF(MY_WME | ME_FATALERROR)))) { if (mem_root->error_handler) (*mem_root->error_handler)(); DBUG_RETURN((void*) 0); /* purecov: inspected */ } mem_root->allocated_size+= get_size; mem_root->block_num++; next->next= *prev; next->size= (uint)get_size; next->left= (uint)(get_size-ALIGN_SIZE(sizeof(USED_MEM))); *prev=next; } point= (uchar*) ((char*) next+ (next->size-next->left)); /*TODO: next part may be unneded due to mem_root->first_block_usage counter*/ if ((next->left-= (uint)length) < mem_root->min_malloc) { /* Full block */ *prev= next->next; /* Remove block from list */ next->next= mem_root->used; mem_root->used= next; mem_root->first_block_usage= 0; } DBUG_PRINT("exit",("ptr: 0x%lx", (ulong) point)); DBUG_RETURN((void*) point); #endif } /* Allocate many pointers at the same time. DESCRIPTION ptr1, ptr2, etc all point into big allocated memory area. SYNOPSIS multi_alloc_root() root Memory root ptr1, length1 Multiple arguments terminated by a NULL pointer ptr2, length2 ... ... NULL RETURN VALUE A pointer to the beginning of the allocated memory block in case of success or NULL if out of memory. */ void *multi_alloc_root(MEM_ROOT *root, ...) { va_list args; char **ptr, *start, *res; size_t tot_length, length; DBUG_ENTER("multi_alloc_root"); va_start(args, root); tot_length= 0; while ((ptr= va_arg(args, char **))) { length= va_arg(args, uint); tot_length+= ALIGN_SIZE(length); } va_end(args); if (!(start= (char*) alloc_root(root, tot_length))) DBUG_RETURN(0); /* purecov: inspected */ va_start(args, root); res= start; while ((ptr= va_arg(args, char **))) { *ptr= res; length= va_arg(args, uint); res+= ALIGN_SIZE(length); } va_end(args); DBUG_RETURN((void*) start); } /* Mark all data in blocks free for reusage */ static inline void mark_blocks_free(MEM_ROOT* root) { USED_MEM *next; 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 - (uint)ALIGN_SIZE(sizeof(USED_MEM)); TRASH_MEM(next); } /* 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 - (uint)ALIGN_SIZE(sizeof(USED_MEM)); TRASH_MEM(next); } /* Now everything is set; Indicate that nothing is used anymore */ root->used= 0; root->first_block_usage= 0; } void claim_root(MEM_ROOT *root) { USED_MEM *next,*old; DBUG_ENTER("claim_root"); DBUG_PRINT("enter",("root: 0x%lx", (long) root)); for (next=root->used; next ;) { old=next; next= next->next ; my_claim(old); } for (next=root->free ; next ;) { old=next; next= next->next; my_claim(old); } DBUG_VOID_RETURN; } /* Deallocate everything used by alloc_root or just move used blocks to free list if called with MY_USED_TO_FREE SYNOPSIS free_root() root Memory root MyFlags Flags for what should be freed: MY_MARK_BLOCKS_FREED Don't free blocks, just mark them free MY_KEEP_PREALLOC If this is not set, then free also the preallocated block NOTES One can call this function either with root block initialised with init_alloc_root() or with a zero()-ed block. It's also safe to call this multiple times with the same mem_root. */ void free_root(MEM_ROOT *root, myf MyFlags) { USED_MEM *next,*old; DBUG_ENTER("free_root"); DBUG_PRINT("enter",("root: 0x%lx flags: %u", (long) root, (uint) MyFlags)); 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 ;) { old=next; next= next->next ; if (old != root->pre_alloc) { old->left= old->size; TRASH_MEM(old); my_free(old); } } for (next=root->free ; next ;) { old=next; next= next->next; if (old != root->pre_alloc) { old->left= old->size; TRASH_MEM(old); my_free(old); } } root->used=root->free=0; if (root->pre_alloc) { root->free=root->pre_alloc; root->free->left=root->pre_alloc->size-(uint)ALIGN_SIZE(sizeof(USED_MEM)); root->allocated_size= root->pre_alloc->size; TRASH_MEM(root->pre_alloc); root->free->next=0; } else root->allocated_size= 0; root->block_num= 4; root->first_block_usage= 0; DBUG_VOID_RETURN; } char *strdup_root(MEM_ROOT *root, const char *str) { return strmake_root(root, str, strlen(str)); } char *strmake_root(MEM_ROOT *root, const char *str, size_t len) { char *pos; if ((pos=alloc_root(root,len+1))) { memcpy(pos,str,len); pos[len]=0; } return pos; } void *memdup_root(MEM_ROOT *root, const void *str, size_t len) { char *pos; if ((pos=alloc_root(root,len))) memcpy(pos,str,len); return pos; } /** Check if the set max_capacity is exceeded if the requested size is allocated @param mem_root memory root to check for allocation @param size requested size to be allocated @retval 1 Memory is available @retval 0 Memory is not available */ static inline my_bool is_mem_available(MEM_ROOT *mem_root, size_t size) { if (mem_root->max_capacity) { if ((mem_root->allocated_size + size) > mem_root->max_capacity) return 0; } return 1; } /** set max_capacity for this mem_root. Should be called after init_alloc_root. If the max_capacity specified is less than what is already pre_alloced in init_alloc_root, only the future allocations are affected. @param mem_root memory root to set the max capacity @param max_value Maximum capacity this mem_root can hold */ void set_memroot_max_capacity(MEM_ROOT *mem_root, size_t max_value) { DBUG_ASSERT(alloc_root_inited(mem_root)); mem_root->max_capacity= max_value; } /** Enable/disable error reporting for exceeding max_capacity. If error reporting is enabled, an error is flagged to indicate that the capacity is exceeded. However allocation will still happen for the requested memory. @param mem_root memory root @param report_eroor set to true if error should be reported else set to false */ void set_memroot_error_reporting(MEM_ROOT *mem_root, my_bool report_error) { DBUG_ASSERT(alloc_root_inited(mem_root)); mem_root->error_for_capacity_exceeded= report_error; }