From: Hiroki Awata <castaneai@castaneai.net> On Linux, init_cpu_info() uses sysconf(_SC_NPROCESSORS_ONLN) which returns the host machine's total CPU count, ignoring cgroup CPU bandwidth limits. This causes applications that scale thread counts based on GetSystemInfo().dwNumberOfProcessors to over-subscribe CPUs in container environments (Docker, Kubernetes). Read cgroup v2 cpu.max and cgroup v1 cpu.cfs_quota_us/period_us to determine the effective CPU limit, and clamp the reported processor count accordingly. For cgroup v2, walk up the hierarchy to find the most restrictive quota. Fall back to sysconf when no cgroup limit is configured. Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=59556 Signed-off-by: Hiroki Awata <castaneai@castaneai.net> --- dlls/ntdll/unix/system.c | 149 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 149 insertions(+) diff --git a/dlls/ntdll/unix/system.c b/dlls/ntdll/unix/system.c index aa66ec2654c..3b6506a9d90 100644 --- a/dlls/ntdll/unix/system.c +++ b/dlls/ntdll/unix/system.c @@ -1623,6 +1623,145 @@ static void get_random( void *buf, ULONG len ) #endif } +#ifdef linux +static long read_cgroup_cpu_limit(void) +{ + char line[512], path[512], buf[512], data[512]; + FILE *f; + long quota, period; + long result = 0; + char *s, *last_sep; + + /* Try cgroup v2 first: walk up the hierarchy for the lowest quota */ + f = fopen("/proc/self/cgroup", "r"); + if (f) + { + while (fgets(line, sizeof(line), f)) + { + if (!strncmp(line, "0::", 3)) + { + if ((s = strchr(line + 3, '\n'))) *s = 0; + snprintf(path, sizeof(path), "%s", line + 3); + fclose(f); + + while (*path) + { + snprintf(buf, sizeof(buf), "/sys/fs/cgroup%s/cpu.max", path); + f = fopen(buf, "r"); + if (f) + { + if (fgets(data, sizeof(data), f) && strncmp(data, "max", 3) != 0) + { + quota = strtol(data, &s, 10); + if (*s == ' ') + { + period = strtol(s + 1, NULL, 10); + if (period > 0) + { + long ncpus = (long)((double)quota / period + 0.5); + if (ncpus < 1) ncpus = 1; + if (!result || ncpus < result) result = ncpus; + } + } + } + fclose(f); + if (result == 1) return 1; + } + + last_sep = strrchr(path, '/'); + if (!last_sep) break; + if (last_sep == path && *(path + 1)) + *(path + 1) = 0; /* iterate on "/" too */ + else + *last_sep = 0; + } + + return result; + } + } + fclose(f); + } + + /* cgroup v1 fallback */ + f = fopen("/proc/self/cgroup", "r"); + if (!f) return 0; + + path[0] = 0; + while (fgets(line, sizeof(line), f)) + { + /* look for a line containing "cpu" controller, e.g. "4:cpu,cpuacct:/path" or "4:cpu:/path" */ + char *controllers, *cgroup_path; + s = strchr(line, ':'); + if (!s) continue; + controllers = s + 1; + s = strchr(controllers, ':'); + if (!s) continue; + *s = 0; + cgroup_path = s + 1; + if ((s = strchr(cgroup_path, '\n'))) *s = 0; + + /* check if "cpu" is one of the controllers */ + s = controllers; + while (*s) + { + char *end = s; + while (*end && *end != ',') end++; + if (end - s == 3 && !strncmp(s, "cpu", 3)) + { + snprintf(path, sizeof(path), "%s", cgroup_path); + break; + } + s = *end ? end + 1 : end; + } + if (path[0]) break; + } + fclose(f); + + if (!path[0]) return 0; + + /* try cpu,cpuacct mount point first, then cpu */ + snprintf(buf, sizeof(buf), "/sys/fs/cgroup/cpu,cpuacct%s/cpu.cfs_quota_us", path); + f = fopen(buf, "r"); + if (!f) + { + snprintf(buf, sizeof(buf), "/sys/fs/cgroup/cpu%s/cpu.cfs_quota_us", path); + f = fopen(buf, "r"); + } + if (!f) return 0; + + if (!fgets(buf, sizeof(buf), f)) + { + fclose(f); + return 0; + } + fclose(f); + quota = strtol(buf, NULL, 10); + if (quota <= 0) return 0; + + /* read period */ + snprintf(buf, sizeof(buf), "/sys/fs/cgroup/cpu,cpuacct%s/cpu.cfs_period_us", path); + f = fopen(buf, "r"); + if (!f) + { + snprintf(buf, sizeof(buf), "/sys/fs/cgroup/cpu%s/cpu.cfs_period_us", path); + f = fopen(buf, "r"); + } + if (!f) return 0; + + if (!fgets(buf, sizeof(buf), f)) + { + fclose(f); + return 0; + } + fclose(f); + period = strtol(buf, NULL, 10); + if (period <= 0) return 0; + + result = (long)((double)quota / period + 0.5); + return result < 1 ? 1 : result; +} +#endif + /****************************************************************** * init_cpu_info * @@ -1652,6 +1791,16 @@ void init_cpu_info(void) #else num = 1; FIXME("Detecting the number of processors is not supported.\n"); +#endif +#ifdef linux + { + long cgroup_cpus = read_cgroup_cpu_limit(); + if (cgroup_cpus > 0 && cgroup_cpus < num) + { + TRACE( "limiting to %ld CPUs from cgroup\n", cgroup_cpus ); + num = cgroup_cpus; + } + } #endif peb->NumberOfProcessors = num; init_cpu_model(); -- GitLab https://gitlab.winehq.org/wine/wine/-/merge_requests/10466