#define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include "cgroup_helpers.h" /* * To avoid relying on the system setup, when setup_cgroup_env is called * we create a new mount namespace, and cgroup namespace. The cgroup2 * root is mounted at CGROUP_MOUNT_PATH * * Unfortunately, most people don't have cgroupv2 enabled at this point in time. * It's easier to create our own mount namespace and manage it ourselves. * * We assume /mnt exists. */ #define WALK_FD_LIMIT 16 #define CGROUP_MOUNT_PATH "/mnt" #define CGROUP_WORK_DIR "/cgroup-test-work-dir" #define format_cgroup_path(buf, path) \ snprintf(buf, sizeof(buf), "%s%s%s", CGROUP_MOUNT_PATH, \ CGROUP_WORK_DIR, path) /** * setup_cgroup_environment() - Setup the cgroup environment * * After calling this function, cleanup_cgroup_environment should be called * once testing is complete. * * This function will print an error to stderr and return 1 if it is unable * to setup the cgroup environment. If setup is successful, 0 is returned. */ int setup_cgroup_environment(void) { char cgroup_workdir[PATH_MAX + 1]; format_cgroup_path(cgroup_workdir, ""); if (unshare(CLONE_NEWNS)) { log_err("unshare"); return 1; } if (mount("none", "/", NULL, MS_REC | MS_PRIVATE, NULL)) { log_err("mount fakeroot"); return 1; } if (mount("none", CGROUP_MOUNT_PATH, "cgroup2", 0, NULL)) { log_err("mount cgroup2"); return 1; } /* Cleanup existing failed runs, now that the environment is setup */ cleanup_cgroup_environment(); if (mkdir(cgroup_workdir, 0777) && errno != EEXIST) { log_err("mkdir cgroup work dir"); return 1; } return 0; } static int nftwfunc(const char *filename, const struct stat *statptr, int fileflags, struct FTW *pfwt) { if ((fileflags & FTW_D) && rmdir(filename)) log_err("Removing cgroup: %s", filename); return 0; } static int join_cgroup_from_top(char *cgroup_path) { char cgroup_procs_path[PATH_MAX + 1]; pid_t pid = getpid(); int fd, rc = 0; snprintf(cgroup_procs_path, sizeof(cgroup_procs_path), "%s/cgroup.procs", cgroup_path); fd = open(cgroup_procs_path, O_WRONLY); if (fd < 0) { log_err("Opening Cgroup Procs: %s", cgroup_procs_path); return 1; } if (dprintf(fd, "%d\n", pid) < 0) { log_err("Joining Cgroup"); rc = 1; } close(fd); return rc; } /** * join_cgroup() - Join a cgroup * @path: The cgroup path, relative to the workdir, to join * * This function expects a cgroup to already be created, relative to the cgroup * work dir, and it joins it. For example, passing "/my-cgroup" as the path * would actually put the calling process into the cgroup * "/cgroup-test-work-dir/my-cgroup" * * On success, it returns 0, otherwise on failure it returns 1. */ int join_cgroup(char *path) { char cgroup_path[PATH_MAX + 1]; format_cgroup_path(cgroup_path, path); return join_cgroup_from_top(cgroup_path); } /** * cleanup_cgroup_environment() - Cleanup Cgroup Testing Environment * * This is an idempotent function to delete all temporary cgroups that * have been created during the test, including the cgroup testing work * directory. * * At call time, it moves the calling process to the root cgroup, and then * runs the deletion process. It is idempotent, and should not fail, unless * a process is lingering. * * On failure, it will print an error to stderr, and try to continue. */ void cleanup_cgroup_environment(void) { char cgroup_workdir[PATH_MAX + 1]; format_cgroup_path(cgroup_workdir, ""); join_cgroup_from_top(CGROUP_MOUNT_PATH); nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH | FTW_MOUNT); } /** * create_and_get_cgroup() - Create a cgroup, relative to workdir, and get the FD * @path: The cgroup path, relative to the workdir, to join * * This function creates a cgroup under the top level workdir and returns the * file descriptor. It is idempotent. * * On success, it returns the file descriptor. On failure it returns 0. * If there is a failure, it prints the error to stderr. */ int create_and_get_cgroup(char *path) { char cgroup_path[PATH_MAX + 1]; int fd; format_cgroup_path(cgroup_path, path); if (mkdir(cgroup_path, 0777) && errno != EEXIST) { log_err("mkdiring cgroup"); return 0; } fd = open(cgroup_path, O_RDONLY); if (fd < 0) { log_err("Opening Cgroup"); return 0; } return fd; } t;2017-01-31 23:58:38 +0100 committerIngo Molnar <mingo@kernel.org>2017-02-01 08:37:27 +0100 commitdd86e373e09fb16b83e8adf5c48c421a4ca76468 (patch) tree55703c2ea8584e303e342090614e0aab3509ab21 /net/core/dev.c parent0b3589be9b98994ce3d5aeca52445d1f5627c4ba (diff)
perf/x86/intel/rapl: Make package handling more robust
The package management code in RAPL relies on package mapping being available before a CPU is started. This changed with: 9d85eb9119f4 ("x86/smpboot: Make logical package management more robust") because the ACPI/BIOS information turned out to be unreliable, but that left RAPL in broken state. This was not noticed because on a regular boot all CPUs are online before RAPL is initialized. A possible fix would be to reintroduce the mess which allocates a package data structure in CPU prepare and when it turns out to already exist in starting throw it away later in the CPU online callback. But that's a horrible hack and not required at all because RAPL becomes functional for perf only in the CPU online callback. That's correct because user space is not yet informed about the CPU being onlined, so nothing caan rely on RAPL being available on that particular CPU. Move the allocation to the CPU online callback and simplify the hotplug handling. At this point the package mapping is established and correct. This also adds a missing check for available package data in the event_init() function. Reported-by: Yasuaki Ishimatsu <yasu.isimatu@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Stephane Eranian <eranian@google.com> Cc: Vince Weaver <vincent.weaver@maine.edu> Fixes: 9d85eb9119f4 ("x86/smpboot: Make logical package management more robust") Link: http://lkml.kernel.org/r/20170131230141.212593966@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'net/core/dev.c')