meminfo(2)							   System Calls 							meminfo(2)

NAME

       meminfo - provide information about memory

SYNOPSIS

       #include <sys/types.h>
       #include <sys/mman.h>

       int meminfo(const uint64_t inaddr[], int addr_count, const uint_t info_req[], int info_count, uint64_t outdata[], uint_t validity[]);

PARAMETERS

       inaddr	       array of input addresses; the maximum number of addresses that can be processed for each call is MAX_MEMINFO_CNT

       addr_count      number of addresses

       info_req        array of types of information requested

       info_count      number of pieces of information requested for each address in inaddr

       outdata	       array into which results are placed; array size must be the product of info_count and addr_count

       validity        array  of  size	addr_count containing bitwise result codes; 0th bit evaluates validity of corresponding input address, 1st
		       bit validity of response to first member of info_req, and so on

DESCRIPTION

       The meminfo() function provides information about virtual and physical memory particular to the calling process.  The user or developer	of
       performance  utilities  can  use  this  information  to analyze system memory allocations and develop a better understanding of the factors
       affecting application performance.

       The caller of meminfo() can obtain the following types of information about both virtual and physical memory.

       MEMINFO_VPHYSICAL       physical address corresponding to virtual address

       MEMINFO_VLGRP	       locality group of physical page corresponding to virtual address

       MEMINFO_VPAGESIZE       size of physical page corresponding to virtual address

       MEMINFO_VREPLCNT        number of replicated physical pages corresponding to specified virtual address

       MEMINFO_VREPL | n       nth physical replica of specified virtual address

       MEMINFO_VREPL_LGRP | n  lgrp of nth physical replica of specified virtual address

       MEMINFO_PLGRP	       locality group of specified physical address

RETURN VALUES

       Upon successful completion meminfo() returns 0. Otherwise -1 is returned and errno is set to indicate the error.

ERRORS

       The meminfo() function will fail if:

       EFAULT	       The area pointed to by outdata or validity could not be written, or the data pointed to by info_req or inaddr could not	be
		       read.

       EINVAL	       The value of info_count is greater than 31 or less than 1, or the value of addr_count is less than 1.

EXAMPLES

       Example 1: Print physical pages and page sizes corresponding to a set of virtual addresses.

       The following example prints the physical pages and page sizes corresponding to a set of virtual addresses.

       void
       print_info(void **addrvec, int how_many)
       {
	   static const uint_t info[] = {
	       MEMINFO_VPHYSICAL,
	       MEMINFO_VPAGESIZE
	   };

	   int info_num = sizeof (info) / sizeof (info[0]);
	   int i;

	   uint64_t *inaddr = alloca(sizeof (uint64_t) * how_many);
	   uint64_t *outdata = alloca(sizeof (uint64_t) * how_many * info_num);
	   uint_t *validity = alloca(sizeof (uint_t) * how_many);

	   for (i = 0; i < how_many; i++)
	       inaddr[i] = (uint64_t)addrvec[i];

	   if (meminfo(inaddr, how_many, info, info_num, outdata, validity) < 0) {
	       perror("meminfo");
	       return;
	   }

	   for (i = 0; i < how_many; i++) {
	       if ((validity[i] & 1) == 0)
		   printf("address 0x%llx not part of address space
",
		       inaddr[i]);

	       else if ((validity[i] & 2) == 0)
		   printf("address 0x%llx has no physical page "
		       "associated with it
", inaddr[i]);

	       else {
		   char buff[80];
		   if ((validity[i] & 4) == 0)
		       strcpy(buff, "<Unknown>");
		   else
		       sprintf(buff, "%lld",
			   outdata[i * info_num + 1]);

		   printf("address 0x%llx is backed by physical "
		       "page 0x%llx of size %s
",
		       inaddr[i], outdata[i * info_num], buff);
	       }
	   }
       }

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Stable			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Async-Signal-Safe 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       memcntl(2), mmap(2), gethomelgroup(3C), getpagesize(3C), madvise(3C), sysconf(3C), attributes(5)

SunOS 5.10							    21 Feb 2003 							meminfo(2)