mem.c

来自「linux 操作系统下对系统资源监控程序的编写」· C语言 代码 · 共 92 行

/* $Id: mem.c,v 1.14 2003/10/19 16:55:56 carlos Exp $ */

/* Copyright (C) 1998-99 Martin Baulig
   This file is part of LibGTop 1.0.

   Contributed by Martin Baulig <[e-mail]>, April 1998.

   LibGTop is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License,
   or (at your option) any later version.

   LibGTop is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   for more details.

   You should have received a copy of the GNU General Public License
   along with LibGTop; see the file COPYING. If not, write to the
   Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.
*/

#include <glibtop.h>
#include <glibtop/mem.h>

#include <glibtop_suid.h>

static const unsigned long _glibtop_sysdeps_mem =
(1 << GLIBTOP_MEM_TOTAL) + (1 << GLIBTOP_MEM_USED) +
(1 << GLIBTOP_MEM_FREE) + (1 << GLIBTOP_MEM_LOCKED);

/* define pagetok in terms of pageshift */

#define pagetok(size) ((size) << server->machine.pageshift)

/* Provides information about memory usage. */

void
glibtop_get_mem_p (glibtop *server, glibtop_mem *buf)
{
	glibtop_init_p (server, (1 << GLIBTOP_SYSDEPS_MEM), 0);

	memset (buf, 0, sizeof (glibtop_mem));
	
	/* !!! THE FOLLOWING CODE RUNS SGID KMEM - CHANGE WITH CAUTION !!! */
	
	glibtop_suid_enter (server);
	
	/* get the array of physpage descriptors */
	
	(void) _glibtop_getkval (server, server->machine.pages,
				 (int *) server->machine.physpage,
				 server->machine.bytesize,
				 "array _page");

	glibtop_suid_leave (server);
	
	/* !!! END OF SGID KMEM PART !!! */


	{	/* sum memory statistics */
		register struct page *pp;
		register int cnt;
		register int inuse;
		register int free;
		register int locked;
		
		/* bop thru the array counting page types */

		pp = server->machine.physpage;
		inuse = free = locked = 0;
		for (cnt = server->machine.count; --cnt >= 0; pp++) {
			if (pp->p_free)
				free++;
			else if (pp->p_lock || pp->p_keepcnt > 0)
				locked++;
			else
				inuse++;
		}

		/* convert memory stats to Kbytes */
		
		buf->total  = pagetok (inuse + free);
		buf->used   = pagetok (inuse);
		buf->free   = pagetok (free);
		buf->locked = pagetok (locked);

		buf->flags = _glibtop_sysdeps_mem;
	}
}