非阻塞mlock（） [英] Non-blocking mlock()

问题描述

有没有阻塞的mlock（）这样的东西？在流量较大的情况下，我不希望我的线程阻塞等待I / O。我宁愿只告诉Linux内核使用mlock（）从一个mmap（）的d文件需要什么区域，然后当页面被获取时得到通知。 （据我所知，标准mlock（）调用是阻塞的。）

解决方案

我相信你想要一个组合 madvise（）或 posix_madvise（）和 mincore（） 。

您将使用 madvise 调用来询问内核 MADV_WILLNEED 。然后，您必须使用 mincore 轮询，以检查页面是否已读入内存。

如果系统在负载很重的情况下，页面可能不会被 madvise 调用读取，因此您需要超时和回退到阻塞读取模式。 / p>

Is there such a thing as non-blocking mlock()? Under heavy traffic, I don't want my threads block waiting for I/O. I'd rather just tell the Linux kernel what region I need from a mmap()'d file using mlock() and then get notified when the pages has been fetched. (As far as I know, the standard mlock() call is blocking.)

解决方案

I believe that you want a combination of madvise() or posix_madvise() and mincore().

You would use a madvise call to ask the kernel for MADV_WILLNEED. Then you would have to poll using mincore to check if the pages had been read into memory.

If the system is under heavy memory load it is possible for the pages to never be read in by the madvise call, so you would need a timeout and a fallback to a blocking read mode.

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