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author | Ben Cheng <bccheng@google.com> | 2013-03-28 11:14:20 -0700 |
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committer | Ben Cheng <bccheng@google.com> | 2013-03-28 12:40:33 -0700 |
commit | af0c51ac87ab2a87caa03fa108f0d164987a2764 (patch) | |
tree | 4b8b470f7c5b69642fdab8d0aa1fbc148d02196b /gcc-4.8/libgo/runtime/malloc.h | |
parent | d87cae247d39ebf4f5a6bf25c932a14d2fdb9384 (diff) | |
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[GCC 4.8] Initial check-in of GCC 4.8.0
Change-Id: I0719d8a6d0f69b367a6ab6f10eb75622dbf12771
Diffstat (limited to 'gcc-4.8/libgo/runtime/malloc.h')
-rw-r--r-- | gcc-4.8/libgo/runtime/malloc.h | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/gcc-4.8/libgo/runtime/malloc.h b/gcc-4.8/libgo/runtime/malloc.h new file mode 100644 index 000000000..a82077420 --- /dev/null +++ b/gcc-4.8/libgo/runtime/malloc.h @@ -0,0 +1,508 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Memory allocator, based on tcmalloc. +// http://goog-perftools.sourceforge.net/doc/tcmalloc.html + +// The main allocator works in runs of pages. +// Small allocation sizes (up to and including 32 kB) are +// rounded to one of about 100 size classes, each of which +// has its own free list of objects of exactly that size. +// Any free page of memory can be split into a set of objects +// of one size class, which are then managed using free list +// allocators. +// +// The allocator's data structures are: +// +// FixAlloc: a free-list allocator for fixed-size objects, +// used to manage storage used by the allocator. +// MHeap: the malloc heap, managed at page (4096-byte) granularity. +// MSpan: a run of pages managed by the MHeap. +// MCentral: a shared free list for a given size class. +// MCache: a per-thread (in Go, per-M) cache for small objects. +// MStats: allocation statistics. +// +// Allocating a small object proceeds up a hierarchy of caches: +// +// 1. Round the size up to one of the small size classes +// and look in the corresponding MCache free list. +// If the list is not empty, allocate an object from it. +// This can all be done without acquiring a lock. +// +// 2. If the MCache free list is empty, replenish it by +// taking a bunch of objects from the MCentral free list. +// Moving a bunch amortizes the cost of acquiring the MCentral lock. +// +// 3. If the MCentral free list is empty, replenish it by +// allocating a run of pages from the MHeap and then +// chopping that memory into a objects of the given size. +// Allocating many objects amortizes the cost of locking +// the heap. +// +// 4. If the MHeap is empty or has no page runs large enough, +// allocate a new group of pages (at least 1MB) from the +// operating system. Allocating a large run of pages +// amortizes the cost of talking to the operating system. +// +// Freeing a small object proceeds up the same hierarchy: +// +// 1. Look up the size class for the object and add it to +// the MCache free list. +// +// 2. If the MCache free list is too long or the MCache has +// too much memory, return some to the MCentral free lists. +// +// 3. If all the objects in a given span have returned to +// the MCentral list, return that span to the page heap. +// +// 4. If the heap has too much memory, return some to the +// operating system. +// +// TODO(rsc): Step 4 is not implemented. +// +// Allocating and freeing a large object uses the page heap +// directly, bypassing the MCache and MCentral free lists. +// +// The small objects on the MCache and MCentral free lists +// may or may not be zeroed. They are zeroed if and only if +// the second word of the object is zero. The spans in the +// page heap are always zeroed. When a span full of objects +// is returned to the page heap, the objects that need to be +// are zeroed first. There are two main benefits to delaying the +// zeroing this way: +// +// 1. stack frames allocated from the small object lists +// can avoid zeroing altogether. +// 2. the cost of zeroing when reusing a small object is +// charged to the mutator, not the garbage collector. +// +// This C code was written with an eye toward translating to Go +// in the future. Methods have the form Type_Method(Type *t, ...). + +typedef struct MCentral MCentral; +typedef struct MHeap MHeap; +typedef struct MSpan MSpan; +typedef struct MStats MStats; +typedef struct MLink MLink; +typedef struct MTypes MTypes; + +enum +{ + PageShift = 12, + PageSize = 1<<PageShift, + PageMask = PageSize - 1, +}; +typedef uintptr PageID; // address >> PageShift + +enum +{ + // Computed constant. The definition of MaxSmallSize and the + // algorithm in msize.c produce some number of different allocation + // size classes. NumSizeClasses is that number. It's needed here + // because there are static arrays of this length; when msize runs its + // size choosing algorithm it double-checks that NumSizeClasses agrees. + NumSizeClasses = 61, + + // Tunable constants. + MaxSmallSize = 32<<10, + + FixAllocChunk = 128<<10, // Chunk size for FixAlloc + MaxMCacheListLen = 256, // Maximum objects on MCacheList + MaxMCacheSize = 2<<20, // Maximum bytes in one MCache + MaxMHeapList = 1<<(20 - PageShift), // Maximum page length for fixed-size list in MHeap. + HeapAllocChunk = 1<<20, // Chunk size for heap growth + + // Number of bits in page to span calculations (4k pages). + // On 64-bit, we limit the arena to 128GB, or 37 bits. + // On 32-bit, we don't bother limiting anything, so we use the full 32-bit address. +#if __SIZEOF_POINTER__ == 8 + MHeapMap_Bits = 37 - PageShift, +#else + MHeapMap_Bits = 32 - PageShift, +#endif + + // Max number of threads to run garbage collection. + // 2, 3, and 4 are all plausible maximums depending + // on the hardware details of the machine. The garbage + // collector scales well to 8 cpus. + MaxGcproc = 8, +}; + +// Maximum memory allocation size, a hint for callers. +// This must be a #define instead of an enum because it +// is so large. +#if __SIZEOF_POINTER__ == 8 +#define MaxMem (1ULL<<(MHeapMap_Bits+PageShift)) /* 128 GB */ +#else +#define MaxMem ((uintptr)-1) +#endif + +// A generic linked list of blocks. (Typically the block is bigger than sizeof(MLink).) +struct MLink +{ + MLink *next; +}; + +// SysAlloc obtains a large chunk of zeroed memory from the +// operating system, typically on the order of a hundred kilobytes +// or a megabyte. If the pointer argument is non-nil, the caller +// wants a mapping there or nowhere. +// +// SysUnused notifies the operating system that the contents +// of the memory region are no longer needed and can be reused +// for other purposes. The program reserves the right to start +// accessing those pages in the future. +// +// SysFree returns it unconditionally; this is only used if +// an out-of-memory error has been detected midway through +// an allocation. It is okay if SysFree is a no-op. +// +// SysReserve reserves address space without allocating memory. +// If the pointer passed to it is non-nil, the caller wants the +// reservation there, but SysReserve can still choose another +// location if that one is unavailable. +// +// SysMap maps previously reserved address space for use. + +void* runtime_SysAlloc(uintptr nbytes); +void runtime_SysFree(void *v, uintptr nbytes); +void runtime_SysUnused(void *v, uintptr nbytes); +void runtime_SysMap(void *v, uintptr nbytes); +void* runtime_SysReserve(void *v, uintptr nbytes); + +// FixAlloc is a simple free-list allocator for fixed size objects. +// Malloc uses a FixAlloc wrapped around SysAlloc to manages its +// MCache and MSpan objects. +// +// Memory returned by FixAlloc_Alloc is not zeroed. +// The caller is responsible for locking around FixAlloc calls. +// Callers can keep state in the object but the first word is +// smashed by freeing and reallocating. +struct FixAlloc +{ + uintptr size; + void *(*alloc)(uintptr); + void (*first)(void *arg, byte *p); // called first time p is returned + void *arg; + MLink *list; + byte *chunk; + uint32 nchunk; + uintptr inuse; // in-use bytes now + uintptr sys; // bytes obtained from system +}; + +void runtime_FixAlloc_Init(FixAlloc *f, uintptr size, void *(*alloc)(uintptr), void (*first)(void*, byte*), void *arg); +void* runtime_FixAlloc_Alloc(FixAlloc *f); +void runtime_FixAlloc_Free(FixAlloc *f, void *p); + + +// Statistics. +// Shared with Go: if you edit this structure, also edit type MemStats in mem.go. +struct MStats +{ + // General statistics. + uint64 alloc; // bytes allocated and still in use + uint64 total_alloc; // bytes allocated (even if freed) + uint64 sys; // bytes obtained from system (should be sum of xxx_sys below, no locking, approximate) + uint64 nlookup; // number of pointer lookups + uint64 nmalloc; // number of mallocs + uint64 nfree; // number of frees + + // Statistics about malloc heap. + // protected by mheap.Lock + uint64 heap_alloc; // bytes allocated and still in use + uint64 heap_sys; // bytes obtained from system + uint64 heap_idle; // bytes in idle spans + uint64 heap_inuse; // bytes in non-idle spans + uint64 heap_released; // bytes released to the OS + uint64 heap_objects; // total number of allocated objects + + // Statistics about allocation of low-level fixed-size structures. + // Protected by FixAlloc locks. + uint64 stacks_inuse; // bootstrap stacks + uint64 stacks_sys; + uint64 mspan_inuse; // MSpan structures + uint64 mspan_sys; + uint64 mcache_inuse; // MCache structures + uint64 mcache_sys; + uint64 buckhash_sys; // profiling bucket hash table + + // Statistics about garbage collector. + // Protected by stopping the world during GC. + uint64 next_gc; // next GC (in heap_alloc time) + uint64 last_gc; // last GC (in absolute time) + uint64 pause_total_ns; + uint64 pause_ns[256]; + uint32 numgc; + bool enablegc; + bool debuggc; + + // Statistics about allocation size classes. + struct { + uint32 size; + uint64 nmalloc; + uint64 nfree; + } by_size[NumSizeClasses]; +}; + +extern MStats mstats + __asm__ (GOSYM_PREFIX "runtime.VmemStats"); + + +// Size classes. Computed and initialized by InitSizes. +// +// SizeToClass(0 <= n <= MaxSmallSize) returns the size class, +// 1 <= sizeclass < NumSizeClasses, for n. +// Size class 0 is reserved to mean "not small". +// +// class_to_size[i] = largest size in class i +// class_to_allocnpages[i] = number of pages to allocate when +// making new objects in class i +// class_to_transfercount[i] = number of objects to move when +// taking a bunch of objects out of the central lists +// and putting them in the thread free list. + +int32 runtime_SizeToClass(int32); +extern int32 runtime_class_to_size[NumSizeClasses]; +extern int32 runtime_class_to_allocnpages[NumSizeClasses]; +extern int32 runtime_class_to_transfercount[NumSizeClasses]; +extern void runtime_InitSizes(void); + + +// Per-thread (in Go, per-M) cache for small objects. +// No locking needed because it is per-thread (per-M). +typedef struct MCacheList MCacheList; +struct MCacheList +{ + MLink *list; + uint32 nlist; + uint32 nlistmin; +}; + +struct MCache +{ + MCacheList list[NumSizeClasses]; + uintptr size; + intptr local_cachealloc; // bytes allocated (or freed) from cache since last lock of heap + intptr local_objects; // objects allocated (or freed) from cache since last lock of heap + intptr local_alloc; // bytes allocated (or freed) since last lock of heap + uintptr local_total_alloc; // bytes allocated (even if freed) since last lock of heap + uintptr local_nmalloc; // number of mallocs since last lock of heap + uintptr local_nfree; // number of frees since last lock of heap + uintptr local_nlookup; // number of pointer lookups since last lock of heap + int32 next_sample; // trigger heap sample after allocating this many bytes + // Statistics about allocation size classes since last lock of heap + struct { + uintptr nmalloc; + uintptr nfree; + } local_by_size[NumSizeClasses]; + +}; + +void* runtime_MCache_Alloc(MCache *c, int32 sizeclass, uintptr size, int32 zeroed); +void runtime_MCache_Free(MCache *c, void *p, int32 sizeclass, uintptr size); +void runtime_MCache_ReleaseAll(MCache *c); + +// MTypes describes the types of blocks allocated within a span. +// The compression field describes the layout of the data. +// +// MTypes_Empty: +// All blocks are free, or no type information is available for +// allocated blocks. +// The data field has no meaning. +// MTypes_Single: +// The span contains just one block. +// The data field holds the type information. +// The sysalloc field has no meaning. +// MTypes_Words: +// The span contains multiple blocks. +// The data field points to an array of type [NumBlocks]uintptr, +// and each element of the array holds the type of the corresponding +// block. +// MTypes_Bytes: +// The span contains at most seven different types of blocks. +// The data field points to the following structure: +// struct { +// type [8]uintptr // type[0] is always 0 +// index [NumBlocks]byte +// } +// The type of the i-th block is: data.type[data.index[i]] +enum +{ + MTypes_Empty = 0, + MTypes_Single = 1, + MTypes_Words = 2, + MTypes_Bytes = 3, +}; +struct MTypes +{ + byte compression; // one of MTypes_* + bool sysalloc; // whether (void*)data is from runtime_SysAlloc + uintptr data; +}; + +// An MSpan is a run of pages. +enum +{ + MSpanInUse = 0, + MSpanFree, + MSpanListHead, + MSpanDead, +}; +struct MSpan +{ + MSpan *next; // in a span linked list + MSpan *prev; // in a span linked list + PageID start; // starting page number + uintptr npages; // number of pages in span + MLink *freelist; // list of free objects + uint32 ref; // number of allocated objects in this span + int32 sizeclass; // size class + uintptr elemsize; // computed from sizeclass or from npages + uint32 state; // MSpanInUse etc + int64 unusedsince; // First time spotted by GC in MSpanFree state + uintptr npreleased; // number of pages released to the OS + byte *limit; // end of data in span + MTypes types; // types of allocated objects in this span +}; + +void runtime_MSpan_Init(MSpan *span, PageID start, uintptr npages); + +// Every MSpan is in one doubly-linked list, +// either one of the MHeap's free lists or one of the +// MCentral's span lists. We use empty MSpan structures as list heads. +void runtime_MSpanList_Init(MSpan *list); +bool runtime_MSpanList_IsEmpty(MSpan *list); +void runtime_MSpanList_Insert(MSpan *list, MSpan *span); +void runtime_MSpanList_Remove(MSpan *span); // from whatever list it is in + + +// Central list of free objects of a given size. +struct MCentral +{ + Lock; + int32 sizeclass; + MSpan nonempty; + MSpan empty; + int32 nfree; +}; + +void runtime_MCentral_Init(MCentral *c, int32 sizeclass); +int32 runtime_MCentral_AllocList(MCentral *c, int32 n, MLink **first); +void runtime_MCentral_FreeList(MCentral *c, int32 n, MLink *first); +void runtime_MCentral_FreeSpan(MCentral *c, MSpan *s, int32 n, MLink *start, MLink *end); + +// Main malloc heap. +// The heap itself is the "free[]" and "large" arrays, +// but all the other global data is here too. +struct MHeap +{ + Lock; + MSpan free[MaxMHeapList]; // free lists of given length + MSpan large; // free lists length >= MaxMHeapList + MSpan **allspans; + uint32 nspan; + uint32 nspancap; + + // span lookup + MSpan *map[1<<MHeapMap_Bits]; + + // range of addresses we might see in the heap + byte *bitmap; + uintptr bitmap_mapped; + byte *arena_start; + byte *arena_used; + byte *arena_end; + + // central free lists for small size classes. + // the union makes sure that the MCentrals are + // spaced CacheLineSize bytes apart, so that each MCentral.Lock + // gets its own cache line. + union { + MCentral; + byte pad[CacheLineSize]; + } central[NumSizeClasses]; + + FixAlloc spanalloc; // allocator for Span* + FixAlloc cachealloc; // allocator for MCache* +}; +extern MHeap runtime_mheap; + +void runtime_MHeap_Init(MHeap *h, void *(*allocator)(uintptr)); +MSpan* runtime_MHeap_Alloc(MHeap *h, uintptr npage, int32 sizeclass, int32 acct, int32 zeroed); +void runtime_MHeap_Free(MHeap *h, MSpan *s, int32 acct); +MSpan* runtime_MHeap_Lookup(MHeap *h, void *v); +MSpan* runtime_MHeap_LookupMaybe(MHeap *h, void *v); +void runtime_MGetSizeClassInfo(int32 sizeclass, uintptr *size, int32 *npages, int32 *nobj); +void* runtime_MHeap_SysAlloc(MHeap *h, uintptr n); +void runtime_MHeap_MapBits(MHeap *h); +void runtime_MHeap_Scavenger(void*); + +void* runtime_mallocgc(uintptr size, uint32 flag, int32 dogc, int32 zeroed); +int32 runtime_mlookup(void *v, byte **base, uintptr *size, MSpan **s); +void runtime_gc(int32 force); +void runtime_markallocated(void *v, uintptr n, bool noptr); +void runtime_checkallocated(void *v, uintptr n); +void runtime_markfreed(void *v, uintptr n); +void runtime_checkfreed(void *v, uintptr n); +extern int32 runtime_checking; +void runtime_markspan(void *v, uintptr size, uintptr n, bool leftover); +void runtime_unmarkspan(void *v, uintptr size); +bool runtime_blockspecial(void*); +void runtime_setblockspecial(void*, bool); +void runtime_purgecachedstats(MCache*); +void* runtime_new(const Type *); +#define runtime_cnew(T) runtime_new(T) + +void runtime_settype(void*, uintptr); +void runtime_settype_flush(M*, bool); +void runtime_settype_sysfree(MSpan*); +uintptr runtime_gettype(void*); + +enum +{ + // flags to malloc + FlagNoPointers = 1<<0, // no pointers here + FlagNoProfiling = 1<<1, // must not profile + FlagNoGC = 1<<2, // must not free or scan for pointers +}; + +typedef struct Obj Obj; +struct Obj +{ + byte *p; // data pointer + uintptr n; // size of data in bytes + uintptr ti; // type info +}; + +void runtime_MProf_Malloc(void*, uintptr); +void runtime_MProf_Free(void*, uintptr); +void runtime_MProf_GC(void); +void runtime_MProf_Mark(void (*addroot)(Obj)); +int32 runtime_gcprocs(void); +void runtime_helpgc(int32 nproc); +void runtime_gchelper(void); + +struct __go_func_type; +bool runtime_getfinalizer(void *p, bool del, void (**fn)(void*), const struct __go_func_type **ft); +void runtime_walkfintab(void (*fn)(void*), void (*scan)(Obj)); + +enum +{ + TypeInfo_SingleObject = 0, + TypeInfo_Array = 1, + TypeInfo_Map = 2, + + // Enables type information at the end of blocks allocated from heap + DebugTypeAtBlockEnd = 0, +}; + +// defined in mgc0.go +void runtime_gc_m_ptr(Eface*); +void runtime_gc_itab_ptr(Eface*); + +void runtime_memorydump(void); + +void runtime_time_scan(void (*)(Obj)); +void runtime_trampoline_scan(void (*)(Obj)); |