https://github.com/torvalds/linux
Revision 88a57667f2990f00b019d46c8426441c9e516d51 authored by Linus Torvalds on 19 December 2014, 21:15:24 UTC, committed by Linus Torvalds on 19 December 2014, 21:15:24 UTC
Pull perf fixes and cleanups from Ingo Molnar:
 "A kernel fix plus mostly tooling fixes, but also some tooling
  restructuring and cleanups"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
  perf: Fix building warning on ARM 32
  perf symbols: Fix use after free in filename__read_build_id
  perf evlist: Use roundup_pow_of_two
  tools: Adopt roundup_pow_of_two
  perf tools: Make the mmap length autotuning more robust
  tools: Adopt rounddown_pow_of_two and deps
  tools: Adopt fls_long and deps
  tools: Move bitops.h from tools/perf/util to tools/
  tools: Introduce asm-generic/bitops.h
  tools lib: Move asm-generic/bitops/find.h code to tools/include and tools/lib
  tools: Whitespace prep patches for moving bitops.h
  tools: Move code originally from asm-generic/atomic.h into tools/include/asm-generic/
  tools: Move code originally from linux/log2.h to tools/include/linux/
  tools: Move __ffs implementation to tools/include/asm-generic/bitops/__ffs.h
  perf evlist: Do not use hard coded value for a mmap_pages default
  perf trace: Let the perf_evlist__mmap autosize the number of pages to use
  perf evlist: Improve the strerror_mmap method
  perf evlist: Clarify sterror_mmap variable names
  perf evlist: Fixup brown paper bag on "hint" for --mmap-pages cmdline arg
  perf trace: Provide a better explanation when mmap fails
  ...
2 parent s 34b85e3 + ac931f8
Raw File
Tip revision: 88a57667f2990f00b019d46c8426441c9e516d51 authored by Linus Torvalds on 19 December 2014, 21:15:24 UTC
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Tip revision: 88a5766
reciprocal_div.c
#include <linux/kernel.h>
#include <asm/div64.h>
#include <linux/reciprocal_div.h>
#include <linux/export.h>

/*
 * For a description of the algorithm please have a look at
 * include/linux/reciprocal_div.h
 */

struct reciprocal_value reciprocal_value(u32 d)
{
	struct reciprocal_value R;
	u64 m;
	int l;

	l = fls(d - 1);
	m = ((1ULL << 32) * ((1ULL << l) - d));
	do_div(m, d);
	++m;
	R.m = (u32)m;
	R.sh1 = min(l, 1);
	R.sh2 = max(l - 1, 0);

	return R;
}
EXPORT_SYMBOL(reciprocal_value);
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