The “Resident set size” (“Working set size” on Windows) is the amount of physical memory (RAM) used by a process’s code and data. Monitoring size changes is an important way to find memory leaks and improve performance, but methods to get this data differ between Windows, Linux, OSX, BSD, Solaris, and others. This article provides cross-platform functions to get the peak (maximum) and current resident set size of a process, and explains what works on what OS.
源码：
/*
* Author: David Robert Nadeau
* Site: http://NadeauSoftware.com/
* License: Creative Commons Attribution 3.0 Unported License
* http://creativecommons.org/licenses/by/3.0/deed.en_US
*/
#if defined(_WIN32)
#include <windows.h>
#include <psapi.h>
#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
#include <unistd.h>
#include <sys/resource.h>
#if defined(__APPLE__) && defined(__MACH__)
#include <mach/mach.h>
#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
#include <fcntl.h>
#include <procfs.h>
#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
#include <stdio.h>
#endif
#else
#error "Cannot define getPeakRSS( ) or getCurrentRSS( ) for an unknown OS."
#endif
/**
* Returns the peak (maximum so far) resident set size (physical
* memory use) measured in bytes, or zero if the value cannot be
* determined on this OS.
*/
size_t getPeakRSS( )
{
#if defined(_WIN32)
/* Windows -------------------------------------------------- */
PROCESS_MEMORY_COUNTERS info;
GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
return (size_t)info.PeakWorkingSetSize;
#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
/* AIX and Solaris ------------------------------------------ */
struct psinfo psinfo;
int fd = -1;
if ( (fd = open( "/proc/self/psinfo", O_RDONLY )) == -1 )
return (size_t)0L; /* Can't open? */
if ( read( fd, &psinfo, sizeof(psinfo) ) != sizeof(psinfo) )
{
close( fd );
return (size_t)0L; /* Can't read? */
}
close( fd );
return (size_t)(psinfo.pr_rssize * 1024L);
#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
/* BSD, Linux, and OSX -------------------------------------- */
struct rusage rusage;
getrusage( RUSAGE_SELF, &rusage );
#if defined(__APPLE__) && defined(__MACH__)
return (size_t)rusage.ru_maxrss;
#else
return (size_t)(rusage.ru_maxrss * 1024L);
#endif
#else
/* Unknown OS ----------------------------------------------- */
return (size_t)0L; /* Unsupported. */
#endif
}
/**
* Returns the current resident set size (physical memory use) measured
* in bytes, or zero if the value cannot be determined on this OS.
*/
size_t getCurrentRSS( )
{
#if defined(_WIN32)
/* Windows -------------------------------------------------- */
PROCESS_MEMORY_COUNTERS info;
GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
return (size_t)info.WorkingSetSize;
#elif defined(__APPLE__) && defined(__MACH__)
/* OSX ------------------------------------------------------ */
struct mach_task_basic_info info;
mach_msg_type_number_t infoCount = MACH_TASK_BASIC_INFO_COUNT;
if ( task_info( mach_task_self( ), MACH_TASK_BASIC_INFO,
(task_info_t)&info, &infoCount ) != KERN_SUCCESS )
return (size_t)0L; /* Can't access? */
return (size_t)info.resident_size;
#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
/* Linux ---------------------------------------------------- */
long rss = 0L;
FILE* fp = NULL;
if ( (fp = fopen( "/proc/self/statm", "r" )) == NULL )
return (size_t)0L; /* Can't open? */
if ( fscanf( fp, "%*s%ld", &rss ) != 1 )
{
fclose( fp );
return (size_t)0L; /* Can't read? */
}
fclose( fp );
return (size_t)rss * (size_t)sysconf( _SC_PAGESIZE);
#else
/* AIX, BSD, Solaris, and Unknown OS ------------------------ */
return (size_t)0L; /* Unsupported. */
#endif
}