140 lines
3.9 KiB
C++
140 lines
3.9 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 <memory>
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#include "logs.h"
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#include "util.h"
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namespace cpu {
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static const std::string listCpusInSet(cpu_set_t* mask) {
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std::string ret;
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for (size_t i = 0; i < CPU_SETSIZE; i++) {
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if (CPU_ISSET(i, mask)) {
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if (!ret.empty()) {
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ret.append(",");
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}
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ret.append(std::to_string(i));
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}
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}
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return ret;
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}
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static size_t getNthOnlineCpu(cpu_set_t* mask, size_t n) {
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for (size_t i = 0, j = 0; i < CPU_SETSIZE; i++) {
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if (CPU_ISSET(i, mask)) {
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if (j == n) {
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return i;
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}
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j++;
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}
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}
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LOG_F("No CPU #%zu found, yet there should be %zu left in the mask [%s]", n,
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(size_t)CPU_COUNT(mask), listCpusInSet(mask).c_str());
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return 0;
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}
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static void setRandomCpu(cpu_set_t* orig_mask, cpu_set_t* new_mask, size_t available_cpus) {
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if (available_cpus == 0) {
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LOG_F("There are no more CPUs left to use, and there should be at least 1 left");
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}
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size_t n = util::rnd64() % available_cpus;
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n = getNthOnlineCpu(orig_mask, n);
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CPU_SET(n, new_mask);
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LOG_D("Add CPU #%zu from the original mask=[%s] (size=%zu, available_cpus=%zu), new "
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"mask=[%s] (size=%zu)",
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n, listCpusInSet(orig_mask).c_str(), (size_t)CPU_COUNT(orig_mask), available_cpus,
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listCpusInSet(new_mask).c_str(), (size_t)CPU_COUNT(new_mask));
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CPU_CLR(n, orig_mask);
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}
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bool initCpu(nsjconf_t* nsjconf) {
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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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std::unique_ptr<cpu_set_t> orig_mask(new cpu_set_t);
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if (!orig_mask) {
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PLOG_W("Failure allocating cpu_set_t");
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return false;
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}
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if (sched_getaffinity(0, CPU_ALLOC_SIZE(CPU_SETSIZE), orig_mask.get()) == -1) {
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PLOG_W("sched_getaffinity(0, mask_size=%zu)", (size_t)CPU_ALLOC_SIZE(CPU_SETSIZE));
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return false;
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}
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size_t available_cpus = CPU_COUNT(orig_mask.get());
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LOG_D("Original CPU set: [%s], with %zu allowed CPUs",
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listCpusInSet(orig_mask.get()).c_str(), available_cpus);
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if (nsjconf->max_cpus > available_cpus) {
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LOG_W(
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"Number of requested CPUs is bigger than number of available CPUs (%zu > %zu)",
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nsjconf->max_cpus, available_cpus);
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return true;
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}
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if (nsjconf->max_cpus == available_cpus) {
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LOG_D("All CPUs requested (%zu of %zu)", nsjconf->max_cpus, available_cpus);
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return true;
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}
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std::unique_ptr<cpu_set_t> new_mask(new cpu_set_t);
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if (!new_mask) {
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PLOG_W("Failure allocating cpu_set_t");
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return false;
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}
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CPU_ZERO(new_mask.get());
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for (size_t i = 0; i < nsjconf->max_cpus; i++) {
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setRandomCpu(orig_mask.get(), new_mask.get(), available_cpus);
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available_cpus--;
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}
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LOG_D("Setting new CPU mask=[%s] with %zu allowed CPUs (max_cpus=%zu), %zu CPUs "
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"(CPU_COUNT=%zu) left mask=[%s]",
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listCpusInSet(new_mask.get()).c_str(), nsjconf->max_cpus,
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(size_t)CPU_COUNT(new_mask.get()), available_cpus, (size_t)CPU_COUNT(orig_mask.get()),
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listCpusInSet(orig_mask.get()).c_str());
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if (sched_setaffinity(0, CPU_ALLOC_SIZE(CPU_SETSIZE), new_mask.get()) == -1) {
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PLOG_W("sched_setaffinity(mask=%s size=%zu max_cpus=%zu (CPU_COUNT=%zu)) failed",
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listCpusInSet(new_mask.get()).c_str(), (size_t)CPU_ALLOC_SIZE(CPU_SETSIZE),
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nsjconf->max_cpus, (size_t)CPU_COUNT(new_mask.get()));
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return false;
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}
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return true;
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}
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} // namespace cpu
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