/****************************************************************************** * * Copyright © International Business Machines Corp., 2009 * * 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. * * DESCRIPTION * GCC atomic builtin wrappers * http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html * * AUTHOR * Darren Hart * * HISTORY * 2009-Nov-17: Initial version by Darren Hart * *****************************************************************************/ #ifndef _ATOMIC_H #define _ATOMIC_H typedef struct { volatile int val; } atomic_t; #define ATOMIC_INITIALIZER { 0 } /** * atomic_cmpxchg() - Atomic compare and exchange * @uaddr: The address of the futex to be modified * @oldval: The expected value of the futex * @newval: The new value to try and assign the futex * * Return the old value of addr->val. */ static inline int atomic_cmpxchg(atomic_t *addr, int oldval, int newval) { return __sync_val_compare_and_swap(&addr->val, oldval, newval); } /** * atomic_inc() - Atomic incrememnt * @addr: Address of the variable to increment * * Return the new value of addr->val. */ static inline int atomic_inc(atomic_t *addr) { return __sync_add_and_fetch(&addr->val, 1); } /** * atomic_dec() - Atomic decrement * @addr: Address of the variable to decrement * * Return the new value of addr-val. */ static inline int atomic_dec(atomic_t *addr) { return __sync_sub_and_fetch(&addr->val, 1); } /** * atomic_set() - Atomic set * @addr: Address of the variable to set * @newval: New value for the atomic_t * * Return the new value of addr->val. */ static inline int atomic_set(atomic_t *addr, int newval) { addr->val = newval; return newval; } #endif inux/net-next.git/commit/tools/perf/ui/stdio?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/perf/ui/stdio
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/perf/ui/stdio')