Messages in this thread Patch in this message | | | From | Valentin Schneider <> | Subject | [RFC PATCH v3 3/3] DEBUG-DO-NOT-MERGE: workqueue: kworker spawner | Date | Tue, 2 Aug 2022 09:41:46 +0100 |
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--- kernel/Makefile | 2 +- kernel/workqueue.c | 9 +++++- kernel/wqstress.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 78 insertions(+), 2 deletions(-) create mode 100644 kernel/wqstress.c
diff --git a/kernel/Makefile b/kernel/Makefile index a7e1f49ab2b3..860133f7bca5 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -10,7 +10,7 @@ obj-y = fork.o exec_domain.o panic.o \ extable.o params.o platform-feature.o \ kthread.o sys_ni.o nsproxy.o \ notifier.o ksysfs.o cred.o reboot.o \ - async.o range.o smpboot.o ucount.o regset.o + async.o range.o smpboot.o ucount.o regset.o wqstress.o obj-$(CONFIG_USERMODE_DRIVER) += usermode_driver.o obj-$(CONFIG_MODULES) += kmod.o diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 28cd58c684ee..4ffd50a3db46 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -91,7 +91,7 @@ enum { BUSY_WORKER_HASH_ORDER = 6, /* 64 pointers */ MAX_IDLE_WORKERS_RATIO = 4, /* 1/4 of busy can be idle */ - IDLE_WORKER_TIMEOUT = 300 * HZ, /* keep idle ones for 5 mins */ + IDLE_WORKER_TIMEOUT = 3 * HZ, /* keep idle ones for 5 mins */ MAYDAY_INITIAL_TIMEOUT = HZ / 100 >= 2 ? HZ / 100 : 2, /* call for help after 10ms @@ -1996,6 +1996,10 @@ static void reap_workers(struct list_head *reaplist) struct worker *worker, *tmp; list_for_each_entry_safe(worker, tmp, reaplist, entry) { + pr_info("WORKER_REAP: task=%s cpu=%d this_task=%s this_cpu=%d\n", + worker->task->comm, task_cpu(worker->task), + current->comm, raw_smp_processor_id()); + list_del_init(&worker->entry); unbind_worker(worker); @@ -2489,6 +2493,9 @@ static int worker_thread(void *__worker) WARN_ON_ONCE(!list_empty(&worker->entry)); set_pf_worker(false); + pr_info("WORKER_DIE: task=%s this_cpu=%d\n", + current->comm, raw_smp_processor_id()); + set_task_comm(worker->task, "kworker/dying"); ida_free(&pool->worker_ida, worker->id); worker_detach_from_pool(worker); diff --git a/kernel/wqstress.c b/kernel/wqstress.c new file mode 100644 index 000000000000..16a3771027cd --- /dev/null +++ b/kernel/wqstress.c @@ -0,0 +1,69 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> + +MODULE_AUTHOR("Valentin Schneider <vschneid@redhat.com>"); +MODULE_LICENSE("GPL"); + +#define TARGET_CPU 3 + +static void wqstress_workfn(struct work_struct *work) +{ + schedule_timeout_interruptible(10 * HZ); +} + +#define DECL_WORK(n) static DECLARE_WORK(wqstress_work_##n, wqstress_workfn) +#define KICK_WORK(n) do { \ + schedule_work_on(TARGET_CPU, &wqstress_work_##n); \ + } while (0); +#define FLUSH_WORK(n) do { \ + flush_work(&wqstress_work_##n); \ + } while (0); + +DECL_WORK(0); +DECL_WORK(1); +DECL_WORK(2); +DECL_WORK(3); +DECL_WORK(4); +DECL_WORK(5); +DECL_WORK(6); +DECL_WORK(7); +DECL_WORK(8); +DECL_WORK(9); + +/* + * This should create ≈(N-1) extra kworkers for N kicked work + */ +static int __init wqstress_init(void) +{ + pr_info("WQSTRESS START\n"); + + sched_set_fifo_low(current); + + KICK_WORK(0); + KICK_WORK(1); + KICK_WORK(2); + KICK_WORK(3); + KICK_WORK(4); + KICK_WORK(5); + KICK_WORK(6); + KICK_WORK(7); + KICK_WORK(8); + KICK_WORK(9); + + FLUSH_WORK(0); + FLUSH_WORK(1); + FLUSH_WORK(2); + FLUSH_WORK(3); + FLUSH_WORK(4); + FLUSH_WORK(5); + FLUSH_WORK(6); + FLUSH_WORK(7); + FLUSH_WORK(8); + FLUSH_WORK(9); + + return 0; +} + +late_initcall_sync(wqstress_init); -- 2.31.1
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