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cleanup: expand tab to 4 spaces
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chrox
@@ -2,98 +2,98 @@
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A global LRU cache
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]]--
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local function calcFreeMem()
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local meminfo = io.open("/proc/meminfo", "r")
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local freemem = 0
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if meminfo then
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for line in meminfo:lines() do
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local free, buffer, cached, n
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free, n = line:gsub("^MemFree:%s-(%d+) kB", "%1")
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if n ~= 0 then freemem = freemem + tonumber(free)*1024 end
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buffer, n = line:gsub("^Buffers:%s-(%d+) kB", "%1")
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if n ~= 0 then freemem = freemem + tonumber(buffer)*1024 end
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cached, n = line:gsub("^Cached:%s-(%d+) kB", "%1")
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if n ~= 0 then freemem = freemem + tonumber(cached)*1024 end
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end
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meminfo:close()
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end
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return freemem
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local meminfo = io.open("/proc/meminfo", "r")
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local freemem = 0
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if meminfo then
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for line in meminfo:lines() do
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local free, buffer, cached, n
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free, n = line:gsub("^MemFree:%s-(%d+) kB", "%1")
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if n ~= 0 then freemem = freemem + tonumber(free)*1024 end
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buffer, n = line:gsub("^Buffers:%s-(%d+) kB", "%1")
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if n ~= 0 then freemem = freemem + tonumber(buffer)*1024 end
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cached, n = line:gsub("^Cached:%s-(%d+) kB", "%1")
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if n ~= 0 then freemem = freemem + tonumber(cached)*1024 end
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end
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meminfo:close()
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end
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return freemem
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end
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local function calcCacheMemSize()
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local min = DGLOBAL_CACHE_SIZE_MINIMUM
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local max = DGLOBAL_CACHE_SIZE_MAXIMUM
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local calc = calcFreeMem()*(DGLOBAL_CACHE_FREE_PROPORTION or 0)
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return math.min(max, math.max(min, calc))
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local min = DGLOBAL_CACHE_SIZE_MINIMUM
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local max = DGLOBAL_CACHE_SIZE_MAXIMUM
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local calc = calcFreeMem()*(DGLOBAL_CACHE_FREE_PROPORTION or 0)
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return math.min(max, math.max(min, calc))
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end
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local Cache = {
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-- cache configuration:
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max_memsize = calcCacheMemSize(),
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-- cache state:
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current_memsize = 0,
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-- associative cache
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cache = {},
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-- this will hold the LRU order of the cache
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cache_order = {}
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-- cache configuration:
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max_memsize = calcCacheMemSize(),
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-- cache state:
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current_memsize = 0,
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-- associative cache
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cache = {},
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-- this will hold the LRU order of the cache
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cache_order = {}
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}
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function Cache:new(o)
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o = o or {}
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setmetatable(o, self)
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self.__index = self
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return o
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o = o or {}
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setmetatable(o, self)
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self.__index = self
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return o
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end
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function Cache:insert(key, object)
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-- guarantee that we have enough memory in cache
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if(object.size > self.max_memsize) then
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-- we're not allowed to claim this much at all
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error("too much memory claimed")
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end
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-- delete objects that least recently used
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-- (they are at the end of the cache_order array)
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while self.current_memsize + object.size > self.max_memsize do
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local removed_key = table.remove(self.cache_order)
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self.current_memsize = self.current_memsize - self.cache[removed_key].size
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self.cache[removed_key]:onFree()
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self.cache[removed_key] = nil
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end
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-- insert new object in front of the LRU order
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table.insert(self.cache_order, 1, key)
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self.cache[key] = object
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self.current_memsize = self.current_memsize + object.size
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-- guarantee that we have enough memory in cache
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if(object.size > self.max_memsize) then
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-- we're not allowed to claim this much at all
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error("too much memory claimed")
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end
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-- delete objects that least recently used
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-- (they are at the end of the cache_order array)
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while self.current_memsize + object.size > self.max_memsize do
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local removed_key = table.remove(self.cache_order)
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self.current_memsize = self.current_memsize - self.cache[removed_key].size
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self.cache[removed_key]:onFree()
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self.cache[removed_key] = nil
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end
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-- insert new object in front of the LRU order
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table.insert(self.cache_order, 1, key)
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self.cache[key] = object
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self.current_memsize = self.current_memsize + object.size
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end
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function Cache:check(key)
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if self.cache[key] then
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if self.cache_order[1] ~= key then
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-- put key in front of the LRU list
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for k, v in ipairs(self.cache_order) do
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if v == key then
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table.remove(self.cache_order, k)
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end
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end
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table.insert(self.cache_order, 1, key)
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end
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return self.cache[key]
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end
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if self.cache[key] then
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if self.cache_order[1] ~= key then
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-- put key in front of the LRU list
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for k, v in ipairs(self.cache_order) do
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if v == key then
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table.remove(self.cache_order, k)
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end
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end
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table.insert(self.cache_order, 1, key)
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end
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return self.cache[key]
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end
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end
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function Cache:willAccept(size)
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-- we only allow single objects to fill 75% of the cache
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if size*4 < self.max_memsize*3 then
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return true
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end
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-- we only allow single objects to fill 75% of the cache
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if size*4 < self.max_memsize*3 then
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return true
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end
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end
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-- blank the cache
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function Cache:clear()
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for k, _ in pairs(self.cache) do
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self.cache[k]:onFree()
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end
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self.cache = {}
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self.cache_order = {}
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self.current_memsize = 0
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for k, _ in pairs(self.cache) do
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self.cache[k]:onFree()
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end
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self.cache = {}
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self.cache_order = {}
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self.current_memsize = 0
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end
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return Cache
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