91 lines
2.4 KiB
C
91 lines
2.4 KiB
C
/*
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nsjail - CPU affinity
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-----------------------------------------
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Copyright 2017 Google Inc. All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#include "cpu.h"
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#include <inttypes.h>
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#include <sched.h>
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#include <stdint.h>
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#include <string.h>
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#include <unistd.h>
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#include "log.h"
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#include "util.h"
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static void cpuSetRandomCpu(cpu_set_t* mask, size_t mask_size, size_t cpu_num) {
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if ((size_t)CPU_COUNT_S(mask_size, mask) >= cpu_num) {
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LOG_F(
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"Number of CPUs in the mask '%d' is bigger than number of available CPUs '%zu'",
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CPU_COUNT(mask), cpu_num);
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}
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for (;;) {
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uint64_t n = utilRnd64() % cpu_num;
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if (!CPU_ISSET_S(n, mask_size, mask)) {
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LOG_D("Setting allowed CPU#:%" PRIu64 " of [0-%zu]", n, cpu_num - 1);
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CPU_SET_S(n, mask_size, mask);
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break;
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}
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}
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}
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bool cpuInit(struct nsjconf_t* nsjconf) {
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if (nsjconf->num_cpus < 0) {
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PLOG_W("sysconf(_SC_NPROCESSORS_ONLN) returned %ld", nsjconf->num_cpus);
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return false;
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}
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if (nsjconf->max_cpus > (size_t)nsjconf->num_cpus) {
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LOG_W("Requested number of CPUs:%zu is bigger than CPUs online:%ld",
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nsjconf->max_cpus, nsjconf->num_cpus);
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return true;
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}
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if (nsjconf->max_cpus == (size_t)nsjconf->num_cpus) {
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LOG_D("All CPUs requested (%zu of %ld)", nsjconf->max_cpus, nsjconf->num_cpus);
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return true;
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}
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if (nsjconf->max_cpus == 0) {
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LOG_D("No max_cpus limit set");
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return true;
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}
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cpu_set_t* mask = CPU_ALLOC(nsjconf->num_cpus);
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if (mask == NULL) {
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PLOG_W("Failure allocating cpu_set_t for %ld CPUs", nsjconf->num_cpus);
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return false;
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}
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size_t mask_size = CPU_ALLOC_SIZE(nsjconf->num_cpus);
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CPU_ZERO_S(mask_size, mask);
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for (size_t i = 0; i < nsjconf->max_cpus; i++) {
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cpuSetRandomCpu(mask, mask_size, nsjconf->num_cpus);
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}
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if (sched_setaffinity(0, mask_size, mask) == -1) {
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PLOG_W("sched_setaffinity(max_cpus=%zu) failed", nsjconf->max_cpus);
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CPU_FREE(mask);
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return false;
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}
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CPU_FREE(mask);
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return true;
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}
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