如何从内核获取总物理内存

Question

我正在使用linux/mm.h

struct sysinfo mem_info;

然后totalMemory = mem_info.totalram;

这给了我设备多少内存。 现在，如何获取正在使用的内存量？ 我真的很讨厌它必须经历每个运行的过程并计算所使用的ram的总和。

Answer 1

遵循普通Linux实用程序的最基本方法是，将/proc/meminfo文件作为文本打开并进行解析。

这是busybox实施的示例：

/*
 * Revert to manual parsing, which incidentally already has the
 * sizes in kilobytes. This should be safe for both 2.4 and
 * 2.6.
 */
 fscanf(fp, "MemFree: %lu %s\n", &mfree, buf);

/*
 * MemShared: is no longer present in 2.6. Report this as 0,
 * to maintain consistent behavior with normal procps.
 */
if (fscanf(fp, "MemShared: %lu %s\n", &shared, buf) != 2)
    shared = 0;

fscanf(fp, "Buffers: %lu %s\n", &buffers, buf);
fscanf(fp, "Cached: %lu %s\n", &cached, buf);

此处的第535行： http ： //code.metager.de/source/xref/busybox/procps/top.c