| | 1 | /*- |
| | 2 | * Copyright (c) 1990, 1993 |
| | 3 | * The Regents of the University of California. All rights reserved. |
| | 4 | * |
| | 5 | * Redistribution and use in source and binary forms, with or without |
| | 6 | * modification, are permitted provided that the following conditions |
| | 7 | * are met: |
| | 8 | * 1. Redistributions of source code must retain the above copyright |
| | 9 | * notice, this list of conditions and the following disclaimer. |
| | 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| | 11 | * notice, this list of conditions and the following disclaimer in the |
| | 12 | * documentation and/or other materials provided with the distribution. |
| | 13 | * 3. All advertising materials mentioning features or use of this software |
| | 14 | * must display the following acknowledgement: |
| | 15 | * This product includes software developed by the University of |
| | 16 | * California, Berkeley and its contributors. |
| | 17 | * 4. Neither the name of the University nor the names of its contributors |
| | 18 | * may be used to endorse or promote products derived from this software |
| | 19 | * without specific prior written permission. |
| | 20 | * |
| | 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| | 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| | 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| | 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| | 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| | 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| | 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| | 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| | 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| | 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| | 31 | * SUCH DAMAGE. |
| | 32 | * |
| | 33 | * @(#)proc_compare.c 8.2 (Berkeley) 9/23/93 |
| | 34 | * |
| | 35 | * $DragonFly: src/usr.bin/w/proc_compare.c,v 1.5 2005/06/27 18:38:03 dillon Exp $ |
| | 36 | */ |
| | 37 | |
| | 38 | #include <sys/param.h> |
| | 39 | #include <sys/time.h> |
| | 40 | #include <sys/user.h> |
| | 41 | |
| | 42 | #include "extern.h" |
| | 43 | |
| | 44 | /* |
| | 45 | * Returns 1 if p2 is "better" than p1 |
| | 46 | * |
| | 47 | * The algorithm for picking the "interesting" process is thus: |
| | 48 | * |
| | 49 | * 1) Only foreground processes are eligible - implied. |
| | 50 | * 2) Runnable processes are favored over anything else. The runner |
| | 51 | * with the highest cpu utilization is picked (p_estcpu). Ties are |
| | 52 | * broken by picking the highest pid. |
| | 53 | * 3) The sleeper with the shortest sleep time is next. With ties, |
| | 54 | * we pick out just "short-term" sleepers (P_SINTR == 0). |
| | 55 | * 4) Further ties are broken by picking the highest pid. |
| | 56 | * |
| | 57 | * If you change this, be sure to consider making the change in the kernel |
| | 58 | * too (^T in kern/tty.c). |
| | 59 | * |
| | 60 | * TODO - consider whether pctcpu should be used. |
| | 61 | */ |
| | 62 | |
| | 63 | #define ISRUN(p) (((p)->p_stat == SRUN) || ((p)->p_stat == SIDL)) |
| | 64 | #define TESTAB(a, b) ((a)<<1 | (b)) |
| | 65 | #define ONLYA 2 |
| | 66 | #define ONLYB 1 |
| | 67 | #define BOTH 3 |
| | 68 | |
| | 69 | int |
| | 70 | proc_compare(register struct proc *p1, register struct proc *p2) |
| | 71 | { |
| | 72 | |
| | 73 | if (p1 == NULL) |
| | 74 | return (1); |
| | 75 | /* |
| | 76 | * see if at least one of them is runnable |
| | 77 | */ |
| | 78 | switch (TESTAB(ISRUN(p1), ISRUN(p2))) { |
| | 79 | case ONLYA: |
| | 80 | return (0); |
| | 81 | case ONLYB: |
| | 82 | return (1); |
| | 83 | case BOTH: |
| | 84 | /* |
| | 85 | * tie - favor one with highest recent cpu utilization |
| | 86 | */ |
| | 87 | if (p2->p_usdata.bsd4.estcpu > p1->p_usdata.bsd4.estcpu) |
| | 88 | return (1); |
| | 89 | if (p1->p_usdata.bsd4.estcpu > p2->p_usdata.bsd4.estcpu) |
| | 90 | return (0); |
| | 91 | return (p2->p_pid > p1->p_pid); /* tie - return highest pid */ |
| | 92 | } |
| | 93 | /* |
| | 94 | * weed out zombies |
| | 95 | */ |
| | 96 | switch (TESTAB(p1->p_stat == SZOMB, p2->p_stat == SZOMB)) { |
| | 97 | case ONLYA: |
| | 98 | return (1); |
| | 99 | case ONLYB: |
| | 100 | return (0); |
| | 101 | case BOTH: |
| | 102 | return (p2->p_pid > p1->p_pid); /* tie - return highest pid */ |
| | 103 | } |
| | 104 | /* |
| | 105 | * pick the one with the smallest sleep time |
| | 106 | */ |
| | 107 | if (p2->p_slptime > p1->p_slptime) |
| | 108 | return (0); |
| | 109 | if (p1->p_slptime > p2->p_slptime) |
| | 110 | return (1); |
| | 111 | /* |
| | 112 | * favor one sleeping in a non-interruptible sleep |
| | 113 | */ |
| | 114 | if (p1->p_flag & P_SINTR && (p2->p_flag & P_SINTR) == 0) |
| | 115 | return (1); |
| | 116 | if (p2->p_flag & P_SINTR && (p1->p_flag & P_SINTR) == 0) |
| | 117 | return (0); |
| | 118 | return (p2->p_pid > p1->p_pid); /* tie - return highest pid */ |
| | 119 | } |
projects / dragonfly.git / blame_incremental