103 lines
2.3 KiB
C
103 lines
2.3 KiB
C
/*
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* Copyright (c) 2002-2004 Roland McGrath <roland@redhat.com>
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* Copyright (c) 2009-2018 Dmitry V. Levin <ldv@altlinux.org>
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* All rights reserved.
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*
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* SPDX-License-Identifier: LGPL-2.1-or-later
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*/
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#include "defs.h"
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#include <sched.h>
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static unsigned int
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get_cpuset_size(void)
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{
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static unsigned int cpuset_size;
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if (!cpuset_size) {
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/*
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* If the cpuset size passed to sched_getaffinity is less
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* than necessary to store the bitmask, the kernel does not
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* look at the mask pointer and fails with EINVAL.
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*
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* If the cpuset size is large enough, the kernel fails with
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* EFAULT on inaccessible mask pointers.
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*
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* This undocumented kernel feature can be used to probe
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* the kernel and find out the minimal valid cpuset size
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* without allocating any memory for the CPU affinity mask.
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*/
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cpuset_size = 128;
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while (cpuset_size &&
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sched_getaffinity(0, cpuset_size, NULL) == -1 &&
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EINVAL == errno) {
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cpuset_size <<= 1;
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}
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if (!cpuset_size)
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cpuset_size = 128;
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}
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return cpuset_size;
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}
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static void
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print_affinitylist(struct tcb *const tcp, const kernel_ulong_t addr,
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const unsigned int len)
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{
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const unsigned int max_size = get_cpuset_size();
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const unsigned int umove_size = len < max_size ? len : max_size;
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const unsigned int size =
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(umove_size + current_wordsize - 1) & -current_wordsize;
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const unsigned int ncpu = size * 8;
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void *cpu;
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if (!verbose(tcp) || (exiting(tcp) && syserror(tcp)) ||
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!addr || !len || !(cpu = calloc(size, 1))) {
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printaddr(addr);
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return;
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}
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if (!umoven_or_printaddr(tcp, addr, umove_size, cpu)) {
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int i = 0;
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const char *sep = "";
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tprints("[");
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for (;; i++) {
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i = next_set_bit(cpu, i, ncpu);
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if (i < 0)
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break;
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tprintf("%s%d", sep, i);
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sep = ", ";
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}
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if (size < len)
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tprintf("%s...", sep);
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tprints("]");
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}
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free(cpu);
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}
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SYS_FUNC(sched_setaffinity)
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{
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const int pid = tcp->u_arg[0];
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const unsigned int len = tcp->u_arg[1];
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tprintf("%d, %u, ", pid, len);
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print_affinitylist(tcp, tcp->u_arg[2], len);
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return RVAL_DECODED;
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}
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SYS_FUNC(sched_getaffinity)
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{
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const int pid = tcp->u_arg[0];
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const unsigned int len = tcp->u_arg[1];
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if (entering(tcp)) {
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tprintf("%d, %u, ", pid, len);
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} else {
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print_affinitylist(tcp, tcp->u_arg[2], tcp->u_rval);
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}
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return 0;
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}
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