From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=BUG6152_INVALID_DATE_TZ_ABSURD,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,INVALID_DATE_TZ_ABSURD,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08C0BC2BCA1 for ; Fri, 7 Jun 2019 16:24:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7C6920840 for ; Fri, 7 Jun 2019 16:24:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730540AbfFGQY2 (ORCPT ); Fri, 7 Jun 2019 12:24:28 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:50581 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730446AbfFGQY0 (ORCPT ); Fri, 7 Jun 2019 12:24:26 -0400 Received: from [5.158.153.52] (helo=noscherz.tec.linutronix.de.) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.80) (envelope-from ) id 1hZHes-0000ei-BJ; Fri, 07 Jun 2019 18:24:02 +0200 From: John Ogness To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Petr Mladek , Sergey Senozhatsky , Steven Rostedt , Linus Torvalds , Greg Kroah-Hartman , Andrea Parri , Thomas Gleixner , Sergey Senozhatsky Subject: [RFC PATCH v2 2/2] printk-rb: add test module Date: Fri, 7 Jun 2019 18:29:49 +0206 Message-Id: <20190607162349.18199-3-john.ogness@linutronix.de> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190607162349.18199-1-john.ogness@linutronix.de> References: <20190607162349.18199-1-john.ogness@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This module does some heavy write stress testing on the ringbuffer with a reader that is checking for integrity. Signed-off-by: John Ogness --- lib/Makefile | 2 + lib/test_prb.c | 237 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 239 insertions(+) create mode 100644 lib/test_prb.c diff --git a/lib/Makefile b/lib/Makefile index fb7697031a79..9a485274b6ba 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -292,3 +292,5 @@ obj-$(CONFIG_GENERIC_LIB_MULDI3) += muldi3.o obj-$(CONFIG_GENERIC_LIB_CMPDI2) += cmpdi2.o obj-$(CONFIG_GENERIC_LIB_UCMPDI2) += ucmpdi2.o obj-$(CONFIG_OBJAGG) += objagg.o + +obj-m += test_prb.o diff --git a/lib/test_prb.c b/lib/test_prb.c new file mode 100644 index 000000000000..2c365028f4e4 --- /dev/null +++ b/lib/test_prb.c @@ -0,0 +1,237 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include + +/* + * This is a test module that starts "num_online_cpus() - 1" writer threads + * and 1 reader thread. The writer threads each write strings of varying + * length. They do this as fast as they can. + * + * The reader thread reads as fast as it can and performs sanity checks on + * the data. + * + * Because the threads are running in such tight loops, they will call + * schedule() from time to time so the system stays alive. + * + * If either the writers or the reader encounter an error, the test is + * aborted. Test results are recorded to the ftrace buffers. The test can + * be aborted manually by removing the module. (Ideally the test should + * never abort on its own.) + */ + +struct rbdata { + int len; + char text[0]; +}; + +static char *test_running; +static int halt_test; + +static void dump_rb(struct printk_ringbuffer *rb) +{ + DECLARE_PRINTKRB_ENTRY(entry, 140); + DECLARE_PRINTKRB_ITER(iter, rb, &entry); + struct rbdata *dat; + u64 last_seq = 0; + int len; + + trace_printk("BEGIN full dump\n"); + + prb_for_each_entry(&iter, len) { + if (entry.seq - last_seq != 1) { + trace_printk("LOST %llu\n", + entry.seq - (last_seq + 1)); + } + last_seq = entry.seq; + + dat = (struct rbdata *)&entry.buffer[0]; + + trace_printk("seq=%llu len=%d textlen=%d dataval=%s\n", + entry.seq, len, dat->len, dat->text); + } + + trace_printk("END full dump\n"); +} + +DECLARE_PRINTKRB(test_rb, 7, 5); + +static int prbtest_writer(void *data) +{ + unsigned long num = (unsigned long)data; + struct prb_reserved_entry e; + char id = 'A' + num; + struct rbdata *dat; + int count = 0; + int len; + + pr_err("prbtest: start thread %lu (writer)\n", num); + + for (;;) { + len = sizeof(struct rbdata) + (prandom_u32() & 0x7f) + 1; + + dat = (struct rbdata *)prb_reserve(&e, &test_rb, len); + if (dat) { + len -= sizeof(struct rbdata) + 1; + memset(&dat->text[0], id, len); + dat->text[len] = 0; + dat->len = len; + prb_commit(&e); + } else { + WRITE_ONCE(halt_test, 1); + trace_printk("writer%lu (%c) failed to reserve\n", + num, id); + } + + if ((count++ & 0x3fff) == 0) + schedule(); + + if (READ_ONCE(halt_test) == 1) + break; + } + + pr_err("prbtest: end thread %lu (writer)\n", num); + + test_running[num] = 0; + + return 0; +} + +static int prbtest_reader(void *data) +{ + unsigned long num = (unsigned long)data; + DECLARE_PRINTKRB_ENTRY(entry, 140); + DECLARE_PRINTKRB_ITER(iter, &test_rb, &entry); + unsigned long total_lost = 0; + unsigned long max_lost = 0; + struct rbdata *dat; + int did_sched = 1; + u64 last_seq = 0; + int count = 0; + int len; + + pr_err("prbtest: start thread %lu (reader)\n", num); + + for (;;) { + prb_for_each_entry(&iter, len) { + if (entry.seq - last_seq != 1 && !did_sched) { + total_lost += entry.seq - (last_seq + 1); + if (max_lost < entry.seq - (last_seq + 1)) + max_lost = entry.seq - (last_seq + 1); + } + last_seq = entry.seq; + did_sched = 0; + + dat = (struct rbdata *)&entry.buffer[0]; + + len = strlen(dat->text); + if (len != dat->len) { + WRITE_ONCE(halt_test, 1); + trace_printk("reader%lu invalid length\n", + num); + } + while (len) { + len--; + if (dat->text[len] != dat->text[0]) { + WRITE_ONCE(halt_test, 1); + trace_printk("reader%lu invalid data\n", + num); + } + } + + if ((count++ & 0x3fff) == 0) { + did_sched = 1; + schedule(); + } + + if (READ_ONCE(halt_test) == 1) + goto out; + } + } +out: + pr_err("reader%lu: total_lost=%lu max_lost=%lu seq=%llu\n", + num, total_lost, max_lost, entry.seq); + pr_err("prbtest: end thread %lu (reader)\n", num); + + test_running[num] = 0; + + return 0; +} + +static int module_test_running; + +static int start_test(void *arg) +{ + struct task_struct *thread; + unsigned long i; + int num_cpus; + + num_cpus = num_online_cpus(); + test_running = kzalloc(num_cpus, GFP_KERNEL); + if (!test_running) + return -ENOMEM; + + module_test_running = 1; + + pr_err("prbtest: starting test\n"); + + for (i = 0; i < num_cpus; i++) { + test_running[i] = 1; + if (i < num_cpus - 1) { + thread = kthread_run(prbtest_writer, (void *)i, + "prbtest writer"); + } else { + thread = kthread_run(prbtest_reader, (void *)i, + "prbtest reader"); + } + if (IS_ERR(thread)) { + pr_err("prbtest: unable to create thread %lu\n", i); + test_running[i] = 0; + } + } + + for (;;) { + for (i = 0; i < num_cpus; i++) { + if (test_running[i] == 1) + break; + } + if (i == num_cpus) + break; + msleep(1000); + } + + pr_err("prbtest: completed test\n"); + + dump_rb(&test_rb); + + module_test_running = 0; + + kfree(test_running); + + return 0; +} + +static int prbtest_init(void) +{ + kthread_run(start_test, NULL, "prbtest"); + return 0; +} + +static void prbtest_exit(void) +{ + WRITE_ONCE(halt_test, 1); + + while (module_test_running) + msleep(1000); +} + +module_init(prbtest_init); +module_exit(prbtest_exit); + +MODULE_AUTHOR("John Ogness "); +MODULE_DESCRIPTION("printk ringbuffer test"); +MODULE_LICENSE("GPL v2"); -- 2.11.0