/* cpufreq-bench CPUFreq microbenchmark * * Copyright (C) 2008 Christian Kornacker * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include #include #include #include #include #include #include #include #include "config.h" #include "system.h" /** * returns time since epoch in µs * * @retval time **/ long long int get_time() { struct timeval now; gettimeofday(&now, NULL); return (long long int)(now.tv_sec * 1000000LL + now.tv_usec); } /** * sets the cpufreq governor * * @param governor cpufreq governor name * @param cpu cpu for which the governor should be set * * @retval 0 on success * @retval -1 when failed **/ int set_cpufreq_governor(char *governor, unsigned int cpu) { dprintf("set %s as cpufreq governor\n", governor); if (cpupower_is_cpu_online(cpu) != 0) { perror("cpufreq_cpu_exists"); fprintf(stderr, "error: cpu %u does not exist\n", cpu); return -1; } if (cpufreq_modify_policy_governor(cpu, governor) != 0) { perror("cpufreq_modify_policy_governor"); fprintf(stderr, "error: unable to set %s governor\n", governor); return -1; } return 0; } /** * sets cpu affinity for the process * * @param cpu cpu# to which the affinity should be set * * @retval 0 on success * @retval -1 when setting the affinity failed **/ int set_cpu_affinity(unsigned int cpu) { cpu_set_t cpuset; CPU_ZERO(&cpuset); CPU_SET(cpu, &cpuset); dprintf("set affinity to cpu #%u\n", cpu); if (sched_setaffinity(getpid(), sizeof(cpu_set_t), &cpuset) < 0) { perror("sched_setaffinity"); fprintf(stderr, "warning: unable to set cpu affinity\n"); return -1; } return 0; } /** * sets the process priority parameter * * @param priority priority value * * @retval 0 on success * @retval -1 when setting the priority failed **/ int set_process_priority(int priority) { struct sched_param param; dprintf("set scheduler priority to %i\n", priority); param.sched_priority = priority; if (sched_setscheduler(0, SCHEDULER, ¶m) < 0) { perror("sched_setscheduler"); fprintf(stderr, "warning: unable to set scheduler priority\n"); return -1; } return 0; } /** * notifies the user that the benchmark may run some time * * @param config benchmark config values * **/ void prepare_user(const struct config *config) { unsigned long sleep_time = 0; unsigned long load_time = 0; unsigned int round; for (round = 0; round < config->rounds; round++) { sleep_time += 2 * config->cycles * (config->sleep + config->sleep_step * round); load_time += 2 * config->cycles * (config->load + config->load_step * round) + (config->load + config->load_step * round * 4); } if (config->verbose || config->output != stdout) printf("approx. test duration: %im\n", (int)((sleep_time + load_time) / 60000000)); } /** * sets up the cpu affinity and scheduler priority * * @param config benchmark config values * **/ void prepare_system(const struct config *config) { if (config->verbose) printf("set cpu affinity to cpu #%u\n", config->cpu); set_cpu_affinity(config->cpu); switch (config->prio) { case SCHED_HIGH: if (config->verbose) printf("high priority condition requested\n"); set_process_priority(PRIORITY_HIGH); break; case SCHED_LOW: if (config->verbose) printf("low priority condition requested\n"); set_process_priority(PRIORITY_LOW); break; default: if (config->verbose) printf("default priority condition requested\n"); set_process_priority(PRIORITY_DEFAULT); } } sdiff
authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /include/sound/info.h
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'include/sound/info.h')