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authorDenys Vlasenko <vda.linux@googlemail.com>2017-01-29 18:19:29 +0100
committerDenys Vlasenko <vda.linux@googlemail.com>2017-01-29 18:19:29 +0100
commitef0e76cc2783e83c6cbf90bf264b36b6bb60605b (patch)
treeaa4b9f1f75e430ed3de5782fd405bcf6e15f722e
parent205d48e9480e3a60f2bf1094f67d837f1b44aea5 (diff)
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taskset: rewrite to be task size-agnostic
function old new delta packed_usage 31130 31190 +60 taskset_main 623 525 -98 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 1/1 up/down: 60/-98) Total: -38 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat
-rw-r--r--miscutils/taskset.c205
1 files changed, 103 insertions, 102 deletions
diff --git a/miscutils/taskset.c b/miscutils/taskset.c
index fb352ab8d..a87b9bd43 100644
--- a/miscutils/taskset.c
+++ b/miscutils/taskset.c
@@ -8,7 +8,7 @@
8 8
9//config:config TASKSET 9//config:config TASKSET
10//config: bool "taskset" 10//config: bool "taskset"
11//config: default n # doesn't build on some non-x86 targets (m68k) 11//config: default y
12//config: help 12//config: help
13//config: Retrieve or set a processes's CPU affinity. 13//config: Retrieve or set a processes's CPU affinity.
14//config: This requires sched_{g,s}etaffinity support in your libc. 14//config: This requires sched_{g,s}etaffinity support in your libc.
@@ -18,15 +18,15 @@
18//config: default y 18//config: default y
19//config: depends on TASKSET 19//config: depends on TASKSET
20//config: help 20//config: help
21//config: Add code for fancy output. This merely silences a compiler-warning 21//config: Needed for machines with more than 32-64 CPUs:
22//config: and adds about 135 Bytes. May be needed for machines with alot 22//config: affinity parameter 0xHHHHHHHHHHHHHHHHHHHH can be arbitrarily long
23//config: of CPUs. 23//config: in this case. Otherwise, it is limited to sizeof(long).
24 24
25//applet:IF_TASKSET(APPLET(taskset, BB_DIR_USR_BIN, BB_SUID_DROP)) 25//applet:IF_TASKSET(APPLET(taskset, BB_DIR_USR_BIN, BB_SUID_DROP))
26//kbuild:lib-$(CONFIG_TASKSET) += taskset.o 26//kbuild:lib-$(CONFIG_TASKSET) += taskset.o
27 27
28//usage:#define taskset_trivial_usage 28//usage:#define taskset_trivial_usage
29//usage: "[-p] [MASK] [PID | PROG ARGS]" 29//usage: "[-p] [HEXMASK] [PID | PROG ARGS]"
30//usage:#define taskset_full_usage "\n\n" 30//usage:#define taskset_full_usage "\n\n"
31//usage: "Set or get CPU affinity\n" 31//usage: "Set or get CPU affinity\n"
32//usage: "\n -p Operate on an existing PID" 32//usage: "\n -p Operate on an existing PID"
@@ -42,71 +42,80 @@
42//usage: "$ taskset -p 1\n" 42//usage: "$ taskset -p 1\n"
43//usage: "pid 1's current affinity mask: 3\n" 43//usage: "pid 1's current affinity mask: 3\n"
44/* 44/*
45 Not yet implemented: 45 * Not yet implemented:
46 * -a/--all-tasks (affect all threads) 46 * -a/--all-tasks (affect all threads)
47 * needs to get TIDs from /proc/PID/task/ and use _them_ as "pid" in sched_setaffinity(pid)
47 * -c/--cpu-list (specify CPUs via "1,3,5-7") 48 * -c/--cpu-list (specify CPUs via "1,3,5-7")
48 */ 49 */
49 50
50#include <sched.h> 51#include <sched.h>
51#include "libbb.h" 52#include "libbb.h"
52 53
54typedef unsigned long ul;
55#define SZOF_UL (unsigned)(sizeof(ul))
56#define BITS_UL (unsigned)(sizeof(ul)*8)
57#define MASK_UL (unsigned)(sizeof(ul)*8 - 1)
58
53#if ENABLE_FEATURE_TASKSET_FANCY 59#if ENABLE_FEATURE_TASKSET_FANCY
54#define TASKSET_PRINTF_MASK "%s" 60#define TASKSET_PRINTF_MASK "%s"
55/* craft a string from the mask */ 61/* craft a string from the mask */
56static char *from_cpuset(cpu_set_t *mask) 62static char *from_mask(const ul *mask, unsigned sz_in_bytes)
57{ 63{
58 int i; 64 char *str = xzalloc((sz_in_bytes+1) * 2); /* we will leak it */
59 char *ret = NULL; 65 char *p = str;
60 char *str = xzalloc((CPU_SETSIZE / 4) + 1); /* we will leak it */ 66 for (;;) {
61 67 ul v = *mask++;
62 for (i = CPU_SETSIZE - 4; i >= 0; i -= 4) { 68 if (SZOF_UL == 4)
63 int val = 0; 69 p += sprintf(p, "%08lx", v);
64 int off; 70 if (SZOF_UL == 8)
65 for (off = 0; off <= 3; ++off) 71 p += sprintf(p, "%016lx", v);
66 if (CPU_ISSET(i + off, mask)) 72 if (SZOF_UL == 16)
67 val |= 1 << off; 73 p += sprintf(p, "%032lx", v); /* :) */
68 if (!ret && val) 74 sz_in_bytes -= SZOF_UL;
69 ret = str; 75 if ((int)sz_in_bytes <= 0)
70 *str++ = bb_hexdigits_upcase[val] | 0x20; 76 break;
71 } 77 }
72 return ret; 78 while (str[0] == '0' && str[1])
79 str++;
80 return str;
73} 81}
74#else 82#else
75#define TASKSET_PRINTF_MASK "%llx" 83#define TASKSET_PRINTF_MASK "%lx"
76static unsigned long long from_cpuset(cpu_set_t *mask) 84static unsigned long long from_mask(ul *mask, unsigned sz_in_bytes UNUSED_PARAM)
77{ 85{
78 BUILD_BUG_ON(CPU_SETSIZE < 8*sizeof(int)); 86 return *mask;
79
80 /* Take the least significant bits. Assume cpu_set_t is
81 * implemented as an array of unsigned long or unsigned
82 * int.
83 */
84 if (CPU_SETSIZE < 8*sizeof(long))
85 return *(unsigned*)mask;
86 if (CPU_SETSIZE < 8*sizeof(long long))
87 return *(unsigned long*)mask;
88# if BB_BIG_ENDIAN
89 if (sizeof(long long) > sizeof(long)) {
90 /* We can put two long in the long long, but they have to
91 * be swapped: the least significant word comes first in the
92 * array */
93 unsigned long *p = (void*)mask;
94 return p[0] + ((unsigned long long)p[1] << (8*sizeof(long)));
95 }
96# endif
97 return *(unsigned long long*)mask;
98} 87}
99#endif 88#endif
100 89
90static unsigned long *get_aff(int pid, unsigned *sz)
91{
92 int r;
93 unsigned long *mask = NULL;
94 unsigned sz_in_bytes = *sz;
95
96 for (;;) {
97 mask = xrealloc(mask, sz_in_bytes);
98 r = sched_getaffinity(pid, sz_in_bytes, (void*)mask);
99 if (r == 0)
100 break;
101 sz_in_bytes *= 2;
102 if (errno == EINVAL && (int)sz_in_bytes > 0)
103 continue;
104 bb_perror_msg_and_die("can't %cet pid %d's affinity", 'g', pid);
105 }
106 //bb_error_msg("get mask[0]:%lx sz_in_bytes:%d", mask[0], sz_in_bytes);
107 *sz = sz_in_bytes;
108 return mask;
109}
101 110
102int taskset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 111int taskset_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
103int taskset_main(int argc UNUSED_PARAM, char **argv) 112int taskset_main(int argc UNUSED_PARAM, char **argv)
104{ 113{
105 cpu_set_t mask; 114 ul *mask;
115 unsigned mask_size_in_bytes;
106 pid_t pid = 0; 116 pid_t pid = 0;
107 unsigned opt_p; 117 unsigned opt_p;
108 const char *current_new; 118 const char *current_new;
109 char *pid_str;
110 char *aff = aff; /* for compiler */ 119 char *aff = aff; /* for compiler */
111 120
112 /* NB: we mimic util-linux's taskset: -p does not take 121 /* NB: we mimic util-linux's taskset: -p does not take
@@ -119,7 +128,7 @@ int taskset_main(int argc UNUSED_PARAM, char **argv)
119 argv += optind; 128 argv += optind;
120 129
121 if (opt_p) { 130 if (opt_p) {
122 pid_str = *argv++; 131 char *pid_str = *argv++;
123 if (*argv) { /* "-p <aff> <pid> ...rest.is.ignored..." */ 132 if (*argv) { /* "-p <aff> <pid> ...rest.is.ignored..." */
124 aff = pid_str; 133 aff = pid_str;
125 pid_str = *argv; /* NB: *argv != NULL in this case */ 134 pid_str = *argv; /* NB: *argv != NULL in this case */
@@ -132,13 +141,14 @@ int taskset_main(int argc UNUSED_PARAM, char **argv)
132 bb_show_usage(); 141 bb_show_usage();
133 } 142 }
134 143
144 mask_size_in_bytes = SZOF_UL;
145 mask = NULL;
135 current_new = "current\0new"; 146 current_new = "current\0new";
136 if (opt_p) {
137 print_aff: 147 print_aff:
138 if (sched_getaffinity(pid, sizeof(mask), &mask) < 0) 148 mask = get_aff(pid, &mask_size_in_bytes);
139 bb_perror_msg_and_die("can't %cet pid %d's affinity", 'g', pid); 149 if (opt_p) {
140 printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n", 150 printf("pid %d's %s affinity mask: "TASKSET_PRINTF_MASK"\n",
141 pid, current_new, from_cpuset(&mask)); 151 pid, current_new, from_mask(mask, mask_size_in_bytes));
142 if (!*argv) { 152 if (!*argv) {
143 /* Either it was just "-p <pid>", 153 /* Either it was just "-p <pid>",
144 * or it was "-p <aff> <pid>" and we came here 154 * or it was "-p <aff> <pid>" and we came here
@@ -148,72 +158,63 @@ int taskset_main(int argc UNUSED_PARAM, char **argv)
148 *argv = NULL; 158 *argv = NULL;
149 current_new += 8; /* "new" */ 159 current_new += 8; /* "new" */
150 } 160 }
161 memset(mask, 0, mask_size_in_bytes);
151 162
152 /* Affinity was specified, translate it into cpu_set_t */ 163 /* Affinity was specified, translate it into mask */
153 CPU_ZERO(&mask); 164 /* it is always in hex, skip "0x" if it exists */
154 if (!ENABLE_FEATURE_TASKSET_FANCY) { 165 if (aff[0] == '0' && (aff[1]|0x20) == 'x')
155 unsigned i; 166 aff += 2;
156 unsigned long long m;
157 167
168 if (!ENABLE_FEATURE_TASKSET_FANCY) {
158 /* Do not allow zero mask: */ 169 /* Do not allow zero mask: */
159 m = xstrtoull_range(aff, 0, 1, ULLONG_MAX); 170 mask[0] = xstrtoul_range(aff, 16, 1, ULONG_MAX);
160 i = 0;
161 do {
162 if (m & 1)
163 CPU_SET(i, &mask);
164 i++;
165 m >>= 1;
166 } while (m != 0);
167 } else { 171 } else {
168 unsigned i; 172 unsigned i;
169 char *last_byte; 173 char *last_char;
170 char *bin; 174
171 uint8_t bit_in_byte; 175 i = 0; /* bit pos in mask[] */
172 176
173 /* Cheap way to get "long enough" buffer */ 177 /* aff is ASCII hex string, accept very long masks in this form.
174 bin = xstrdup(aff); 178 * Process hex string AABBCCDD... to ulong mask[]
175 179 * from the rightmost nibble, which is least-significant.
176 if (aff[0] != '0' || (aff[1]|0x20) != 'x') { 180 * Bits not fitting into mask[] are ignored: (example: 1234
177/* TODO: decimal/octal masks are still limited to 2^64 */ 181 * in 12340000000000000000000000000000000000000ff)
178 unsigned long long m = xstrtoull_range(aff, 0, 1, ULLONG_MAX); 182 */
179 bin += strlen(bin); 183 last_char = strchrnul(aff, '\0');
180 last_byte = bin - 1; 184 while (last_char > aff) {
181 while (m) { 185 char c;
182 *--bin = m & 0xff; 186 ul val;
183 m >>= 8; 187
184 } 188 last_char--;
185 } else { 189 c = *last_char;
186 /* aff is "0x.....", we accept very long masks in this form */ 190 if (isdigit(c))
187 last_byte = hex2bin(bin, aff + 2, INT_MAX); 191 val = c - '0';
188 if (!last_byte) { 192 else if ((c|0x20) >= 'a' && (c|0x20) <= 'f')
189 bad_aff: 193 val = (c|0x20) - ('a' - 10);
194 else
190 bb_error_msg_and_die("bad affinity '%s'", aff); 195 bb_error_msg_and_die("bad affinity '%s'", aff);
191 }
192 last_byte--; /* now points to the last byte */
193 }
194 196
195 i = 0; 197 if (i < mask_size_in_bytes * 8) {
196 bit_in_byte = 1; 198 mask[i / BITS_UL] |= val << (i & MASK_UL);
197 while (last_byte >= bin) {
198 if (bit_in_byte & *last_byte) {
199 if (i >= CPU_SETSIZE)
200 goto bad_aff;
201 CPU_SET(i, &mask);
202 //bb_error_msg("bit %d set", i); 199 //bb_error_msg("bit %d set", i);
203 } 200 }
204 i++; 201 /* else:
205 /* bit_in_byte is uint8_t! & 0xff is implied */ 202 * We can error out here, but we don't.
206 bit_in_byte = (bit_in_byte << 1); 203 * For one, kernel itself ignores bits in mask[]
207 if (!bit_in_byte) { 204 * which do not map to any CPUs.
208 bit_in_byte = 1; 205 * If mask has one 32-bit long,
209 last_byte--; 206 * but you have only 8 CPUs, all bits beyond first 8
210 } 207 * are ignored, silently.
208 * No point in making bits past 31th to be errors.
209 */
210 i += 4;
211 } 211 }
212 } 212 }
213 213
214 /* Set pid's or our own (pid==0) affinity */ 214 /* Set pid's or our own (pid==0) affinity */
215 if (sched_setaffinity(pid, sizeof(mask), &mask)) 215 if (sched_setaffinity(pid, mask_size_in_bytes, (void*)mask))
216 bb_perror_msg_and_die("can't %cet pid %d's affinity", 's', pid); 216 bb_perror_msg_and_die("can't %cet pid %d's affinity", 's', pid);
217 //bb_error_msg("set mask[0]:%lx", mask[0]);
217 218
218 if (!argv[0]) /* "-p <aff> <pid> [...ignored...]" */ 219 if (!argv[0]) /* "-p <aff> <pid> [...ignored...]" */
219 goto print_aff; /* print new affinity and exit */ 220 goto print_aff; /* print new affinity and exit */
generated by cgit v1.2.3-55-g6feb (git 2.39.1) at 2025-03-23 07:09:36 +0000