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Diffstat (limited to 'mysys/my_alloc.c')
| -rw-r--r-- | mysys/my_alloc.c | 493 |
1 files changed, 493 insertions, 0 deletions
diff --git a/mysys/my_alloc.c b/mysys/my_alloc.c new file mode 100644 index 00000000..3e0b774b --- /dev/null +++ b/mysys/my_alloc.c @@ -0,0 +1,493 @@ +/* + Copyright (c) 2000, 2010, Oracle and/or its affiliates + Copyright (c) 2010, 2020, MariaDB + + 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 02110-1335 USA */ + +/* Routines to handle mallocing of results which will be freed the same time */ + +#include <my_global.h> +#include <my_sys.h> +#include <m_string.h> +#undef EXTRA_DEBUG +#define EXTRA_DEBUG + +/* data packed in MEM_ROOT -> min_malloc */ + +#define MALLOC_FLAG(A) ((A & 1) ? MY_THREAD_SPECIFIC : 0) + +#define TRASH_MEM(X) TRASH_FREE(((char*)(X) + ((X)->size-(X)->left)), (X)->left) + +/* + Initialize memory root + + SYNOPSIS + init_alloc_root() + mem_root - memory root to initialize + name - name of memroot (for debugging) + 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. + my_flags MY_THREAD_SPECIFIC flag for my_malloc + + DESCRIPTION + This function prepares memory root for further use, sets initial size of + chunk for memory allocation and pre-allocates first block if specified. + Although 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. + + We don't want to change the structure size for MEM_ROOT. + Because of this, we store in MY_THREAD_SPECIFIC as bit 1 in block_size +*/ + +void init_alloc_root(PSI_memory_key key, MEM_ROOT *mem_root, size_t block_size, + size_t pre_alloc_size __attribute__((unused)), + myf my_flags) +{ + DBUG_ENTER("init_alloc_root"); + DBUG_PRINT("enter",("root: %p prealloc: %zu", mem_root, pre_alloc_size)); + + 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) & ~1; + if (my_flags & MY_THREAD_SPECIFIC) + mem_root->block_size|= 1; + + 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; + +#if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG)) + if (pre_alloc_size) + { + size_t size= pre_alloc_size + ALIGN_SIZE(sizeof(USED_MEM)); + if ((mem_root->free= mem_root->pre_alloc= + (USED_MEM*) my_malloc(key, size, MYF(my_flags)))) + { + mem_root->free->size= size; + mem_root->free->left= pre_alloc_size; + mem_root->free->next= 0; + TRASH_MEM(mem_root->free); + } + } +#endif + DBUG_VOID_RETURN; +} + +/* + 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 __attribute__((unused))) +{ + DBUG_ENTER("reset_root_defaults"); + DBUG_ASSERT(alloc_root_inited(mem_root)); + + mem_root->block_size= (((block_size - ALLOC_ROOT_MIN_BLOCK_SIZE) & ~1) | + (mem_root->block_size & 1)); +#if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG)) + 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 == size) + { + /* We found a suitable block, no need to do anything else */ + mem_root->pre_alloc= mem; + DBUG_VOID_RETURN; + } + if (mem->left + ALIGN_SIZE(sizeof(USED_MEM)) == mem->size) + { + /* remove block from the list and free it */ + *prev= mem->next; + my_free(mem); + } + else + prev= &mem->next; + } + /* Allocate new prealloc block and add it to the end of free list */ + if ((mem= (USED_MEM *) my_malloc(mem_root->m_psi_key, size, + MYF(MALLOC_FLAG(mem_root-> + block_size))))) + { + mem->size= size; + mem->left= pre_alloc_size; + mem->next= *prev; + *prev= mem_root->pre_alloc= mem; + TRASH_MEM(mem); + } + else + { + mem_root->pre_alloc= 0; + } + } + } + else +#endif + mem_root->pre_alloc= 0; + + DBUG_VOID_RETURN; +} + + +void *alloc_root(MEM_ROOT *mem_root, size_t length) +{ +#if defined(HAVE_valgrind) && defined(EXTRA_DEBUG) + reg1 USED_MEM *next; + DBUG_ENTER("alloc_root"); + DBUG_PRINT("enter",("root: %p", 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 (!(next = (USED_MEM*) my_malloc(mem_root->m_psi_key, length, + MYF(MY_WME | ME_FATAL | + MALLOC_FLAG(mem_root->block_size))))) + { + if (mem_root->error_handler) + (*mem_root->error_handler)(); + DBUG_RETURN((uchar*) 0); /* purecov: inspected */ + } + next->next= mem_root->used; + next->left= 0; + next->size= length; + mem_root->used= next; + DBUG_PRINT("exit",("ptr: %p", (((char*)next)+ALIGN_SIZE(sizeof(USED_MEM))))); + DBUG_RETURN((((uchar*) next)+ALIGN_SIZE(sizeof(USED_MEM)))); +#else + size_t get_size, block_size; + uchar* point; + reg1 USED_MEM *next= 0; + reg2 USED_MEM **prev; + size_t original_length __attribute__((unused)) = length; + DBUG_ENTER("alloc_root"); + DBUG_PRINT("enter",("root: %p", 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) + REDZONE_SIZE; + 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 & ~1) * (mem_root->block_num >> 2); + get_size= length+ALIGN_SIZE(sizeof(USED_MEM)); + get_size= MY_MAX(get_size, block_size); + + if (!(next = (USED_MEM*) my_malloc(mem_root->m_psi_key, get_size, + MYF(MY_WME | ME_FATAL | + MALLOC_FLAG(mem_root-> + block_size))))) + { + if (mem_root->error_handler) + (*mem_root->error_handler)(); + DBUG_RETURN((void*) 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; + TRASH_MEM(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-= 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; + } + point+= REDZONE_SIZE; + TRASH_ALLOC(point, original_length); + DBUG_PRINT("exit",("ptr: %p", 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"); + /* + We don't need to do DBUG_PRINT here as it will be done when alloc_root + is called + */ + + 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); +} + + +#if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG)) +/** 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)); + 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 - 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; + root->block_num= 4; +} +#endif + + +/* + 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 bzero()-ed block. + It's also safe to call this multiple times with the same mem_root. +*/ + +void free_root(MEM_ROOT *root, myf MyFlags) +{ + reg1 USED_MEM *next,*old; + DBUG_ENTER("free_root"); + DBUG_PRINT("enter",("root: %p flags: %lu", root, MyFlags)); + +#if !(defined(HAVE_valgrind) && defined(EXTRA_DEBUG)) + /* + There is no point in using mark_blocks_free when using valgrind as + it will not reclaim any memory + */ + if (MyFlags & MY_MARK_BLOCKS_FREE) + { + mark_blocks_free(root); + DBUG_VOID_RETURN; + } +#endif + if (!(MyFlags & MY_KEEP_PREALLOC)) + root->pre_alloc=0; + + for (next=root->used; next ;) + { + old=next; next= next->next ; + if (old != root->pre_alloc) + my_free(old); + } + for (next=root->free ; next ;) + { + old=next; next= next->next; + if (old != root->pre_alloc) + my_free(old); + } + root->used=root->free=0; + if (root->pre_alloc) + { + root->free=root->pre_alloc; + root->free->left=root->pre_alloc->size-ALIGN_SIZE(sizeof(USED_MEM)); + TRASH_MEM(root->pre_alloc); + 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) +{ + 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))) + { + if (len) + 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)) && len) + memcpy(pos,str,len); + return pos; +} + +LEX_CSTRING safe_lexcstrdup_root(MEM_ROOT *root, const LEX_CSTRING str) +{ + LEX_CSTRING res; + if (str.length) + res.str= strmake_root(root, str.str, str.length); + else + res.str= (const char *)""; + res.length= str.length; + return res; +} |