《内核kernel：获取系统物理内存信息模块编写》

一、模块编写

#include <linux/version.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mm.h>

#define PRT(a, b) pr_info("%-15s=%10d %10ld %8ld\n", \
			 a, b, (PAGE_SIZE*b)/1024, (PAGE_SIZE*b)/1024/1024)

static int __init my_init(void)
{
	struct page *p;
	unsigned long i, pfn, valid = 0;
	int free = 0, locked = 0, reserved = 0, swapcache = 0,
	    referenced = 0, slab = 0, private = 0, uptodate = 0,
	    dirty = 0, active = 0, writeback = 0, mappedtodisk = 0;

	unsigned long num_physpages;

	num_physpages = get_num_physpages();
	for (i = 0; i < num_physpages; i++) {

		/* Most of ARM systems have ARCH_PFN_OFFSET */
		pfn = i + ARCH_PFN_OFFSET;
		/* may be holes due to remapping */
		if (!pfn_valid(pfn))
			continue;

		valid++;
		p = pfn_to_page(pfn);
		if (!p)
			continue;
		/* page_count(page) == 0 is a free page. */
		if (!page_count(p)) {
			free++;
			continue;
		}
		if (PageLocked(p))
			locked++;
		if (PageReserved(p))
			reserved++;
		if (PageSwapCache(p))
			swapcache++;
		if (PageReferenced(p))
			referenced++;
		if (PageSlab(p))
			slab++;
		if (PagePrivate(p))
			private++;
		if (PageUptodate(p))
			uptodate++;
		if (PageDirty(p))
			dirty++;
		if (PageActive(p))
			active++;
		if (PageWriteback(p))
			writeback++;
		if (PageMappedToDisk(p))
			mappedtodisk++;
	}

	pr_info("\nExamining %ld pages (num_phys_pages) = %ld MB\n",
		num_physpages, num_physpages * PAGE_SIZE / 1024 / 1024);
	pr_info("Pages with valid PFN"s=%ld, = %ld MB\n", valid,
		valid * PAGE_SIZE / 1024 / 1024);
	pr_info("\n                     Pages         KB       MB\n\n");

	PRT("free", free);
	PRT("locked", locked);
	PRT("reserved", reserved);
	PRT("swapcache", swapcache);
	PRT("referenced", referenced);
	PRT("slab", slab);
	PRT("private", private);
	PRT("uptodate", uptodate);
	PRT("dirty", dirty);
	PRT("active", active);
	PRT("writeback", writeback);
	PRT("mappedtodisk", mappedtodisk);

	return 0;
}

static void __exit my_exit(void)
{
	pr_info("Module exit\n");
}

module_init(my_init);
module_exit(my_exit);

MODULE_AUTHOR("HarkerYX");
MODULE_LICENSE("GPL v2");
#include <linux/version.h>
#include <linu