CodeFast

linux内核源码解析：linux源码下载及top命令中的RES是如何计算的

https://blog.csdn.net/whbing1471/article/details/108427689

linux源码 -> linux/fs/proc/task_mmu.c -> task_statm()
-->> *resident = *shared + get_mm_counter(mm, MM_ANONPAGES);
     *shared = get_mm_counter(mm, MM_FILEPAGES);
static inline unsigned long get_mm_counter(struct mm_struct *mm, int member)
{
	long val = atomic_long_read(&mm->rss_stat.count[member]);

#ifdef SPLIT_RSS_COUNTING
	/*
	 * counter is updated in asynchronous manner and may go to minus.
	 * But it's never be expected number for users.
	 */
	if (val < 0)
		val = 0;
#endif
	return (unsigned long)val;
}

https://blog.csdn.net/crazycoder8848/article/details/38958075?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522160274880919725222459016%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fall.%2522%257D&request_id=160274880919725222459016&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~all~first_rank_v2~rank_v28-2-38958075.first_rank_ecpm_v3_pc_rank_v2&utm_term=pagemap+%E7%89%A9%E7%90%86%E5%9C%B0%E5%9D%80&spm=1018.2118.3001.4187

#include <stdio.h>
#include <stdint.h>
//#include <sys/types.h>
//#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#define    page_map_file     "/proc/self/pagemap"
#define    PFN_MASK          ((((uint64_t)1)<<55)-1)
#define    PFN_PRESENT_FLAG  (((uint64_t)1)<<63)


int mem_addr_vir2phy(unsigned long vir, unsigned long *phy)
{
	static int fd_init = 0;
	static int fd;
	unsigned long page_size=getpagesize();
	unsigned long vir_page_idx = vir/page_size;
	unsigned long pfn_item_offset = vir_page_idx*sizeof(uint64_t);
	uint64_t pfn_item;

	if(fd_init == 0)
	{
		fd = open(page_map_file, O_RDONLY);
		fd_init = 1;
	}
	if (fd<0)
	{
		close(fd);
		fd_init = 0;
		//printf("open %s failed\n", page_map_file);
		return -1;
	}


	if ((off_t)-1 == lseek(fd, pfn_item_offset, SEEK_SET))
	{
		close(fd);
		fd_init = 0;
		//printf("lseek %s failed", page_map_file);
		return -1;
	}


	if (sizeof(uint64_t) != read(fd, &pfn_item, sizeof(uint64_t)))
	{
		close(fd);
		fd_init = 0;
		//printf("read %s failed", page_map_file);
		return -1;
	}


	if (0==(pfn_item & PFN_PRESENT_FLAG))
	{
		//printf("page is not present");
		return -1;
	}

	*phy = (pfn_item & PFN_MASK)*page_size + vir % page_size;
	return 0;
}


void mem_addr_vir2phy_test(void)
{
	int mem_addr_vir2phy(unsigned long vir, unsigned long *phy);
	unsigned long phy_address;


	int size0 = 1024*1024*32;
	char *pMem0 = (char*)malloc(size0);


	for(int Index = 0; Index < size0; Index+=MB(1)/16)
	{
		int ret = mem_addr_vir2phy((unsigned long)pMem0 + Index, &phy_address);
		if(ret == 0)
			printf("Mem0.malloc %016llX + %2d.%04d MB -> %016llX (%d)\n", pMem0, Index/MB(1), (Index%MB(1))/1024, phy_address, ret);
	}
	for(int Index = 0; Index < 8; Index++)printf("--------- ");printf("\n");
	for(int Index = MB(1); Index < MB(1)+1024; Index++)
	{
		pMem0[Index] = 1;
	}
	for(int Index = 0; Index < size0; Index+=MB(1)/16)
	{
		int ret = mem_addr_vir2phy((unsigned long)pMem0 + Index, &phy_address);
		if(ret == 0)
			printf("Mem1.malloc %016llX + %2d.%04d MB -> %016llX (%d)\n", pMem0, Index/MB(1), (Index%MB(1))/1024, phy_address, ret);
	}
	for(int Index = 0; Index < 8; Index++)printf("--------- ");printf("\n");
	system("top -n 1 -p `pidof test01`|grep test01");
	for(int Index = 0; Index < 8; Index++)printf("--------- ");printf("\n");
	for(int Index = 0; Index < size0; Index++)
	{
		pMem0[Index] = Index;
	}
	system("top -n 1 -p `pidof test01`|grep test01");
	for(int Index = 0; Index < 8; Index++)printf("--------- ");printf("\n");

	return ;
}