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    Annotation of /tags/mkinitrd-6_3_1/busybox/miscutils/taskset.c

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    Revision 1143 - (hide annotations) (download)
    Thu Aug 19 12:44:27 2010 UTC (13 years, 10 months ago) by niro
    File MIME type: text/plain
    File size: 3676 byte(s) 
    tagged 'mkinitrd-6_3_1'
    1 niro 532 /* vi: set sw=4 ts=4: */
    2     /*
    3     * taskset - retrieve or set a processes' CPU affinity
    4 niro 816 * Copyright (c) 2006 Bernhard Reutner-Fischer
    5 niro 532 *
    6     * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
    7     */
    8    
    9     #include <sched.h>
    10 niro 816 #include "libbb.h"
    11 niro 532
    12     #if ENABLE_FEATURE_TASKSET_FANCY
    13     #define TASKSET_PRINTF_MASK "%s"
    14     /* craft a string from the mask */
    15 niro 816 static char *from_cpuset(cpu_set_t *mask)
    16 niro 532 {
    17     int i;
    18 niro 816 char *ret = NULL;
    19     char *str = xzalloc((CPU_SETSIZE / 4) + 1); /* we will leak it */
    20 niro 532
    21     for (i = CPU_SETSIZE - 4; i >= 0; i -= 4) {
    22 niro 816 int val = 0;
    23 niro 532 int off;
    24     for (off = 0; off <= 3; ++off)
    25 niro 816 if (CPU_ISSET(i + off, mask))
    26     val |= 1 << off;
    27 niro 532 if (!ret && val)
    28     ret = str;
    29 niro 816 *str++ = bb_hexdigits_upcase[val] | 0x20;
    30 niro 532 }
    31     return ret;
    32     }
    33     #else
    34 niro 816 #define TASKSET_PRINTF_MASK "%llx"
    35     static unsigned long long from_cpuset(cpu_set_t *mask)
    36     {
    37     struct BUG_CPU_SETSIZE_is_too_small {
    38     char BUG_CPU_SETSIZE_is_too_small[
    39     CPU_SETSIZE < sizeof(int) ? -1 : 1];
    40     };
    41     char *p = (void*)mask;
    42    
    43     /* Take the least significant bits. Careful!
    44     * Consider both CPU_SETSIZE=4 and CPU_SETSIZE=1024 cases
    45     */
    46     #if BB_BIG_ENDIAN
    47     /* For big endian, it means LAST bits */
    48     if (CPU_SETSIZE < sizeof(long))
    49     p += CPU_SETSIZE - sizeof(int);
    50     else if (CPU_SETSIZE < sizeof(long long))
    51     p += CPU_SETSIZE - sizeof(long);
    52     else
    53     p += CPU_SETSIZE - sizeof(long long);
    54 niro 532 #endif
    55 niro 816 if (CPU_SETSIZE < sizeof(long))
    56     return *(unsigned*)p;
    57     if (CPU_SETSIZE < sizeof(long long))
    58     return *(unsigned long*)p;
    59     return *(unsigned long long*)p;
    60     }
    61     #endif
    62 niro 532
    63    
    64 niro 816 int taskset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
    65     int taskset_main(int argc UNUSED_PARAM, char **argv)
    66 niro 532 {
    67 niro 816 cpu_set_t mask;
    68 niro 532 pid_t pid = 0;
    69 niro 816 unsigned opt_p;
    70     const char *current_new;
    71     char *pid_str;
    72     char *aff = aff; /* for compiler */
    73 niro 532
    74 niro 816 /* NB: we mimic util-linux's taskset: -p does not take
    75     * an argument, i.e., "-pN" is NOT valid, only "-p N"!
    76     * Indeed, util-linux-2.13-pre7 uses:
    77     * getopt_long(argc, argv, "+pchV", ...), not "...p:..." */
    78 niro 532
    79 niro 816 opt_complementary = "-1"; /* at least 1 arg */
    80     opt_p = getopt32(argv, "+p");
    81     argv += optind;
    82 niro 532
    83 niro 816 if (opt_p) {
    84     pid_str = *argv++;
    85     if (*argv) { /* "-p <aff> <pid> ...rest.is.ignored..." */
    86     aff = pid_str;
    87     pid_str = *argv; /* NB: *argv != NULL in this case */
    88 niro 532 }
    89 niro 816 /* else it was just "-p <pid>", and *argv == NULL */
    90     pid = xatoul_range(pid_str, 1, ((unsigned)(pid_t)ULONG_MAX) >> 1);
    91     } else {
    92     aff = *argv++; /* <aff> <cmd...> */
    93     if (!*argv)
    94     bb_show_usage();
    95 niro 532 }
    96    
    97 niro 816 current_new = "current\0new";
    98     if (opt_p) {
    99 niro 532 print_aff:
    100     if (sched_getaffinity(pid, sizeof(mask), &mask) < 0)
    101 niro 816 bb_perror_msg_and_die("can't %cet pid %d's affinity", 'g', pid);
    102 niro 532 printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
    103 niro 816 pid, current_new, from_cpuset(&mask));
    104     if (!*argv) {
    105     /* Either it was just "-p <pid>",
    106     * or it was "-p <aff> <pid>" and we came here
    107     * for the second time (see goto below) */
    108 niro 532 return EXIT_SUCCESS;
    109 niro 816 }
    110     *argv = NULL;
    111     current_new += 8; /* "new" */
    112 niro 532 }
    113    
    114 niro 816 { /* Affinity was specified, translate it into cpu_set_t */
    115     unsigned i;
    116     /* Do not allow zero mask: */
    117     unsigned long long m = xstrtoull_range(aff, 0, 1, ULLONG_MAX);
    118     enum { CNT_BIT = CPU_SETSIZE < sizeof(m)*8 ? CPU_SETSIZE : sizeof(m)*8 };
    119    
    120     CPU_ZERO(&mask);
    121     for (i = 0; i < CNT_BIT; i++) {
    122     unsigned long long bit = (1ULL << i);
    123     if (bit & m)
    124     CPU_SET(i, &mask);
    125     }
    126 niro 532 }
    127 niro 816
    128     /* Set pid's or our own (pid==0) affinity */
    129     if (sched_setaffinity(pid, sizeof(mask), &mask))
    130     bb_perror_msg_and_die("can't %cet pid %d's affinity", 's', pid);
    131    
    132 niro 1123 if (!argv[0]) /* "-p <aff> <pid> [...ignored...]" */
    133 niro 816 goto print_aff; /* print new affinity and exit */
    134    
    135 niro 1123 BB_EXECVP_or_die(argv);
    136 niro 532 }