Question

v8是否对单个对象的堆分配有限制？

a = new Array(1024*1024*102)

在节点命令行上失败

FATAL ERROR: JS Allocation failed - process out of memory

此外，当作为脚本

运行时，这会失败并出现相同的错误

node --expose-gc --nouse-idle-notification --max-old-space-size=8192

FATAL ERROR: CALL_AND_RETRY_0 Allocation failed - process out of memory

var util = require('util');
o = {};

while(1) {
    o["hahahahahaha" + String(ctr)] = ctr;
    ctr++;

    if (ctr % 100000 === 0) {
        console.log(util.inspect(process.memoryUsage()));
        if (ctr % 10000000 === 0) gc();
    }
}

最后输出：

{ rss: 1009557504, heapTotal: 993408824, heapUsed: 964980592 }

然而，

var a = [];
while(1) {
    var o = {};
    o["hahahahahaha" + String(ctr)] = ctr;
    a.push(o);
    ctr++;

    if (ctr % 100000 === 0) {
        console.log(ctr);
        console.log(util.inspect(process.memoryUsage()));
        console.log();
        if (ctr % 10000000 === 0) gc();
    }
}

很好

{ rss: 5466140672, heapTotal: 1091224368, heapUsed: 1070460592 }

编辑：

node -v

v0.10.25

uname -a

Linux 3.13.0-24-generic #47-Ubuntu SMP Fri May 2 23:30:00 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

编辑2：即便如此！似乎v8的限制适用于对象可以拥有的属性数量？

while(1) {

    if (!o["hahahahahaha" + String(Math.floor(ctr/1000000))]) {
        o["hahahahahaha" + String(Math.floor(ctr/1000000))] = {};
        console.log(Object.keys(o))
    }
    o["hahahahahaha" + String(Math.floor(ctr/1000000))][String(ctr)] = ctr;
    ctr++;

    if (ctr % 100000 === 0) {
        console.log(ctr);
        console.log(util.inspect(process.memoryUsage()));
        console.log();
        if (ctr % 10000000 === 0) gc();
    }
}

{ rss: 2474512384, heapTotal: 2466405768, heapUsed: 2431583008 }

另外，我发现了这个： https://github.com/v8/v8/blob/master/src/objects.h#L2928

我想知道它是否相关。

Answer 1

事实证明，字符串，对象和数组的最大大小存在硬限制。限制是旧垃圾收集器的残余物。这是相关的票：

https://code.google.com/p/v8/issues/detail?id=3505

Node.js单个对象的堆内存限制

1 个答案: