/* Count leading and trailing zeros functions
 *
 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#ifndef _LINUX_BITOPS_COUNT_ZEROS_H_
#define _LINUX_BITOPS_COUNT_ZEROS_H_

#include <asm/bitops.h>

/**
 * count_leading_zeros - Count the number of zeros from the MSB back
 * @x: The value
 *
 * Count the number of leading zeros from the MSB going towards the LSB in @x.
 *
 * If the MSB of @x is set, the result is 0.
 * If only the LSB of @x is set, then the result is BITS_PER_LONG-1.
 * If @x is 0 then the result is COUNT_LEADING_ZEROS_0.
 */
static inline int count_leading_zeros(unsigned long x)
{
	if (sizeof(x) == 4)
		return BITS_PER_LONG - fls(x);
	else
		return BITS_PER_LONG - fls64(x);
}

#define COUNT_LEADING_ZEROS_0 BITS_PER_LONG

/**
 * count_trailing_zeros - Count the number of zeros from the LSB forwards
 * @x: The value
 *
 * Count the number of trailing zeros from the LSB going towards the MSB in @x.
 *
 * If the LSB of @x is set, the result is 0.
 * If only the MSB of @x is set, then the result is BITS_PER_LONG-1.
 * If @x is 0 then the result is COUNT_TRAILING_ZEROS_0.
 */
static inline int count_trailing_zeros(unsigned long x)
{
#define COUNT_TRAILING_ZEROS_0 (-1)

	if (sizeof(x) == 4)
		return ffs(x);
	else
		return (x != 0) ? __ffs(x) : COUNT_TRAILING_ZEROS_0;
}

#endif /* _LINUX_BITOPS_COUNT_ZEROS_H_ */
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>tools</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>testing</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>selftests</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/rcutorture?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>rcutorture</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/rcutorture/configs?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>configs</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/rcutorture/configs/rcu?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>rcu</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/rcutorture/configs/rcu/TASKS03?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>TASKS03</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;</td><td class='right'>2017-01-30 19:27:10 -0500</td></tr>
<tr><th>committer</th><td>Steven Rostedt (VMware) &lt;rostedt@goodmis.org&gt;</td><td class='right'>2017-01-31 09:13:49 -0500</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/rcutorture/configs/rcu/TASKS03?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>79c6f448c8b79c321e4a1f31f98194e4f6b6cae7</a> (<a href='/cgit.cgi/linux/net-next.git/patch/tools/testing/selftests/rcutorture/configs/rcu/TASKS03?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>patch</a>)</td></tr>
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<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests/rcutorture/configs/rcu/TASKS03?id=0c744ea4f77d72b3dcebb7a8f2684633ec79be88'>0c744ea4f77d72b3dcebb7a8f2684633ec79be88</a> (<a href='/cgit.cgi/linux/net-next.git/diff/tools/testing/selftests/rcutorture/configs/rcu/TASKS03?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7&amp;id2=0c744ea4f77d72b3dcebb7a8f2684633ec79be88'>diff</a>)</td></tr></table>
<div class='commit-subject'>tracing: Fix hwlat kthread migration</div><div class='commit-msg'>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) &lt;rostedt@goodmis.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=79c6f448c8b79c321e4a1f31f98194e4f6b6cae7'>Diffstat</a> (limited to 'tools/testing/selftests/rcutorture/configs/rcu/TASKS03')</div><table summary='diffstat' class='diffstat'>