/
mem_pool.go
134 lines (113 loc) · 2.44 KB
/
mem_pool.go
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package exec
import (
"math"
"sync"
)
var (
EmptyPage = make([]byte, DefaultPageSize)
)
func init() {
for i := 0; i < len(EmptyPage); i++ {
EmptyPage[i] = 0
}
}
type MemBlock struct {
FreeMem [][]byte
memPool *sync.Pool
size int
pages int
}
type MemPool struct {
sync.Mutex
memBlock []*MemBlock
largeMem map[int]*sync.Pool
}
func NewMemBlock(size, pages int) *MemBlock {
block := &MemBlock{size: size, pages: pages}
block.FreeMem = make([][]byte, 0, size)
for i := 0; i < size; i++ {
block.FreeMem = append(block.FreeMem, make([]byte, DefaultPageSize*pages))
}
block.memPool = &sync.Pool{
New: func() interface{} {
return make([]byte, DefaultPageSize*pages)
},
}
return block
}
func (mb *MemBlock) Get() []byte {
length := len(mb.FreeMem)
if length == 0 {
return mb.memPool.Get().([]byte)
}
m := mb.FreeMem[length-1]
mb.FreeMem = mb.FreeMem[0 : length-1]
return m
}
func (mb *MemBlock) Put(mem []byte) {
if len(mem) != mb.pages*DefaultPageSize {
panic("add wrong mem")
}
if len(mb.FreeMem) == mb.size {
mb.memPool.Put(mem)
return
}
mb.FreeMem = append(mb.FreeMem, mem)
}
func NewMemPool(count int, size int) *MemPool {
pool := &MemPool{}
pool.memBlock = make([]*MemBlock, 0, count)
for i := 0; i < count; i++ {
pool.memBlock = append(pool.memBlock, NewMemBlock(size, DefaultMemoryPages+int(math.Pow(2, float64(i)))))
}
pool.largeMem = make(map[int]*sync.Pool)
return pool
}
func (mp *MemPool) Get(pages int) []byte {
mp.Lock()
defer mp.Unlock()
if pages <= 0 {
return nil
}
var mem []byte
pages = fixSize(pages - DefaultMemoryPages)
pos := int(math.Log2(float64(pages)))
if pos >= len(mp.memBlock) {
pool, ok := mp.largeMem[pages]
if !ok {
pool = &sync.Pool{
New: func() interface{} {
return make([]byte, DefaultPageSize*(pages+DefaultMemoryPages))
},
}
mp.largeMem[pages] = pool
}
mem = pool.Get().([]byte)
} else {
mem = mp.memBlock[pos].Get()
}
memset(mem)
return mem
}
func memset(mem []byte) {
pages := len(mem) / DefaultPageSize
for i := 0; i < pages; i++ {
copy(mem[i*DefaultPageSize:(i+1)*DefaultPageSize], EmptyPage)
}
}
func (mp *MemPool) Put(mem []byte) {
mp.Lock()
defer mp.Unlock()
pages := len(mem) / DefaultPageSize
pages = fixSize(pages - DefaultMemoryPages)
pos := int(math.Log2(float64(pages)))
if pos >= len(mp.memBlock) {
pool, ok := mp.largeMem[pages]
if !ok {
return
}
pool.Put(mem)
} else {
mp.memBlock[pos].Put(mem)
}
}