usr/src/sys/h/vmtune.h

/*      vmtune.h        4.1     11/9/80 */

/*
 * Tunable performance parameters
 *
 * These may vary per-cpu due to configuration as well as the flavor of
 * the local job mix.  MAXPGIO in multiplied by the number of swap devices
 * available (nswdev) at boot time.
 */
#define LOOPSIZ         ((maxfree - firstfree) / CLSIZE)
                                        /* loop circumference */
#define LOTSFREE        ((maxfree - firstfree) / 4)
                                        /* very high mark to freeze scans */
#define DESFREE         200             /* minimum desirable free memory */
#define MINFREE         64              /* water mark to run swap daemon */
#define MAXSLP          20              /* max blocked time (in seconds) allowed
                                           before being very swappable */
#define SLOWSCAN        25              /* seconds per loop when memory easy */
#define FASTSCAN        15              /* seconds per loop when memory tight */
#define SAFERSS         32              /* nominal ``small'' resident set size
                                           protected against replacement */
#define MAXPGIO         50              /* max desired paging i/o per second
                                           per paging device, controls max
                                           paging ops per second */
/* WITH MAXPGIO SET TO 50, IT RARELY TAKES OVER */