/* * Kernel module for testing static keys. * * Copyright 2015 Akamai Technologies Inc. All Rights Reserved * * Authors: * Jason Baron * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * 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. */ #include #include /* old keys */ struct static_key base_old_true_key = STATIC_KEY_INIT_TRUE; EXPORT_SYMBOL_GPL(base_old_true_key); struct static_key base_inv_old_true_key = STATIC_KEY_INIT_TRUE; EXPORT_SYMBOL_GPL(base_inv_old_true_key); struct static_key base_old_false_key = STATIC_KEY_INIT_FALSE; EXPORT_SYMBOL_GPL(base_old_false_key); struct static_key base_inv_old_false_key = STATIC_KEY_INIT_FALSE; EXPORT_SYMBOL_GPL(base_inv_old_false_key); /* new keys */ DEFINE_STATIC_KEY_TRUE(base_true_key); EXPORT_SYMBOL_GPL(base_true_key); DEFINE_STATIC_KEY_TRUE(base_inv_true_key); EXPORT_SYMBOL_GPL(base_inv_true_key); DEFINE_STATIC_KEY_FALSE(base_false_key); EXPORT_SYMBOL_GPL(base_false_key); DEFINE_STATIC_KEY_FALSE(base_inv_false_key); EXPORT_SYMBOL_GPL(base_inv_false_key); static void invert_key(struct static_key *key) { if (static_key_enabled(key)) static_key_disable(key); else static_key_enable(key); } static int __init test_static_key_base_init(void) { invert_key(&base_inv_old_true_key); invert_key(&base_inv_old_false_key); invert_key(&base_inv_true_key.key); invert_key(&base_inv_false_key.key); return 0; } static void __exit test_static_key_base_exit(void) { } module_init(test_static_key_base_init); module_exit(test_static_key_base_exit); MODULE_AUTHOR("Jason Baron "); MODULE_LICENSE("GPL"); ='active' href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/ftrace?h=nds-private-remove&id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>commitdiff
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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-30 19:27:10 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-31 09:13:49 -0500
commit79c6f448c8b79c321e4a1f31f98194e4f6b6cae7 (patch)
tree370efda701f03cccf21e02bb1fdd3b852547d75c /tools/testing/selftests/ftrace
parent0c744ea4f77d72b3dcebb7a8f2684633ec79be88 (diff)
tracing: Fix hwlat kthread migration
The hwlat tracer creates a kernel thread at start of the tracer. It is pinned to a single CPU and will move to the next CPU after each period of running. If the user modifies the migration thread's affinity, it will not change after that happens. The original code created the thread at the first instance it was called, but later was changed to destroy the thread after the tracer was finished, and would not be created until the next instance of the tracer was established. The code that initialized the affinity was only called on the initial instantiation of the tracer. After that, it was not initialized, and the previous affinity did not match the current newly created one, making it appear that the user modified the thread's affinity when it did not, and the thread failed to migrate again. Cc: stable@vger.kernel.org Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'tools/testing/selftests/ftrace')