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Yury Norov 2c57a0e233 lib: find_*_bit reimplementation 
This patchset does rework to find_bit function family to achieve better
performance, and decrease size of text.  All rework is done in patch 1.
Patches 2 and 3 are about code moving and renaming.

It was boot-tested on x86_64 and MIPS (big-endian) machines.
Performance tests were ran on userspace with code like this:

	/* addr[] is filled from /dev/urandom */
	start = clock();
	while (ret < nbits)
		ret = find_next_bit(addr, nbits, ret + 1);

	end = clock();
	printf("%ld\t", (unsigned long) end - start);

On Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz measurements are: (for
find_next_bit, nbits is 8M, for find_first_bit - 80K)

	find_next_bit:		find_first_bit:
	new	current		new	current
	26932	43151		14777	14925
	26947	43182		14521	15423
	26507	43824		15053	14705
	27329	43759		14473	14777
	26895	43367		14847	15023
	26990	43693		15103	15163
	26775	43299		15067	15232
	27282	42752		14544	15121
	27504	43088		14644	14858
	26761	43856		14699	15193
	26692	43075		14781	14681
	27137	42969		14451	15061
	...			...

find_next_bit performance gain is 35-40%;
find_first_bit - no measurable difference.

On ARM machine, there is arch-specific implementation for find_bit.

Thanks a lot to George Spelvin and Rasmus Villemoes for hints and
helpful discussions.

This patch (of 3):

New implementations takes less space in source file (see diffstat) and in
object.  For me it's 710 vs 453 bytes of text.  It also shows better
performance.

find_last_bit description fixed due to obvious typo.

[akpm@linux-foundation.org: include linux/bitmap.h, per Rasmus]
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: George Spelvin <linux@horizon.com>
Cc: Alexey Klimov <klimov.linux@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2015-04-17 09:03:53 -04:00
..
fonts fonts: Add 6x10 font 2014-10-09 11:35:48 +03:00
lz4 lib/lz4: Pull out constant tables 2015-03-25 15:04:57 +01:00
lzo lzo: check for length overrun in variable length encoding. 2014-09-28 11:08:01 +02:00
mpi MPILIB: Fix comparison of negative MPIs 2015-01-14 16:10:12 +00:00
raid6 x86/raid6: correctly check for assembler capabilities 2015-02-04 08:35:51 +11:00
reed_solomon
…
xz lib/xz: enable all filters by default in Kconfig 2014-06-04 16:54:18 -07:00
zlib_deflate zlib: clean up some dead code 2014-08-06 18:01:24 -07:00
zlib_inflate zlib: clean up some dead code 2014-08-06 18:01:24 -07:00
.gitignore
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Kconfig Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2015-02-19 10:36:45 -08:00
Kconfig.debug Merge branch 'akpm' (patches from Andrew) 2015-04-14 16:49:17 -07:00
Kconfig.kasan kasan: enable instrumentation of global variables 2015-02-13 21:21:42 -08:00
Kconfig.kgdb kdb: Allow access to sensitive commands to be restricted by default 2014-11-11 09:31:52 -06:00
Kconfig.kmemcheck
…
Makefile move iov_iter.c from mm/ to lib/ 2015-02-17 22:22:17 -05:00
argv_split.c
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asn1_decoder.c lib/asn1_decoder.c: kernel-doc warning fix 2014-06-04 16:54:19 -07:00
assoc_array.c assoc_array: Include rcupdate.h for call_rcu() definition 2015-01-07 16:08:41 +00:00
atomic64.c locking,arch: Rewrite generic atomic support 2014-08-14 12:48:14 +02:00
atomic64_test.c lib/atomic64_test.c: convert printk(KERN_INFO to pr_info 2014-06-04 16:54:19 -07:00
audit.c syscalls: implement execveat() system call 2014-12-13 12:42:51 -08:00
average.c lib: Ensure EWMA does not store wrong intermediate values 2014-01-16 23:46:06 -08:00
bcd.c
…
bch.c
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bitmap.c bitmap, cpumask, nodemask: remove dedicated formatting functions 2015-02-13 21:21:39 -08:00
bitrev.c ARM: 8187/1: add CONFIG_HAVE_ARCH_BITREVERSE to support rbit instruction 2014-12-22 16:43:06 +00:00
bsearch.c
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btree.c lib/btree.c: fix leak of whole btree nodes 2014-06-04 16:54:18 -07:00
bug.c lib/bug: Use RCU list ops for module_bug_list 2014-11-11 17:07:46 +10:30
build_OID_registry
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bust_spinlocks.c
…
check_signature.c
…
checksum.c lib/checksum.c: fix build for generic csum_tcpudp_nofold 2015-01-29 11:57:38 -08:00
clz_ctz.c lib/clz_ctz.c: add prototype declarations in lib/clz_ctz.c 2014-04-03 16:21:12 -07:00
clz_tab.c
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cmdline.c lib: Add a generic cmdline parse function parse_option_str 2014-10-03 18:40:58 +01:00
compat_audit.c audit: Add generic compat syscall support 2014-03-20 10:11:35 -04:00
cordic.c
…
cpu-notifier-error-inject.c
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cpu_rmap.c Remove GENERIC_HARDIRQ config option 2013-09-13 15:09:52 +02:00
cpumask.c lib/cpumask: cpumask_set_cpu_local_first to use all cores when numa node is not defined 2014-07-02 18:29:23 -07:00
crc-ccitt.c
…
crc-itu-t.c
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crc-t10dif.c crypto: crct10dif - Add fallback for broken initrds 2013-09-12 15:31:34 +10:00
crc7.c lib/crc7: Shift crc7() output left 1 bit 2014-05-16 14:26:52 -04:00
crc8.c
…
crc16.c
…
crc32.c lib: crc32: Add some additional __pure annotations 2014-06-25 16:04:00 -07:00
crc32defs.h
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ctype.c
…
debug_locks.c
…
debugobjects.c lib/debugobjects.c: convert printk(KERN_DEBUG to pr_debug 2014-06-04 16:53:53 -07:00
dec_and_lock.c
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decompress.c lib/decompress.c: consistency of compress formats for kernel image 2014-12-13 12:42:52 -08:00
decompress_bunzip2.c decompress_bunzip2: off by one in get_next_block() 2014-12-13 12:42:52 -08:00
decompress_inflate.c initramfs: support initramfs that is bigger than 2GiB 2014-08-08 15:57:26 -07:00
decompress_unlz4.c initramfs: support initramfs that is bigger than 2GiB 2014-08-08 15:57:26 -07:00
decompress_unlzma.c initramfs: support initramfs that is bigger than 2GiB 2014-08-08 15:57:26 -07:00
decompress_unlzo.c initramfs: support initramfs that is bigger than 2GiB 2014-08-08 15:57:26 -07:00
decompress_unxz.c initramfs: support initramfs that is bigger than 2GiB 2014-08-08 15:57:26 -07:00
devres.c devres: support sizes greater than an unsigned long 2014-11-07 10:09:07 -08:00
digsig.c lib/digsig.c: kernel-doc warning fixes 2014-06-04 16:54:19 -07:00
div64.c lib: correct link to the original source for div64_u64 2015-03-06 23:19:27 +01:00
dma-debug.c dma-debug: prevent early callers from crashing 2014-12-10 17:41:02 -08:00
dump_stack.c asmlinkage: Add explicit __visible to drivers/*, lib/*, kernel/* 2014-05-05 16:07:46 -07:00
dynamic_debug.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2015-02-10 18:57:15 -08:00
dynamic_queue_limits.c lib/dynamic_queue_limits.c: simplify includes 2015-02-12 18:54:15 -08:00
earlycpio.c
…
extable.c
…
fault-inject.c fault-inject: add ratelimit option 2014-12-13 12:42:52 -08:00
fdt.c
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fdt_empty_tree.c lib: add fdt_empty_tree.c 2014-04-30 19:49:37 +01:00
fdt_ro.c
…
fdt_rw.c
…
fdt_strerror.c
…
fdt_sw.c
…
fdt_wip.c
…
find_last_bit.c lib: find_*_bit reimplementation 2015-04-17 09:03:53 -04:00
find_next_bit.c lib: find_*_bit reimplementation 2015-04-17 09:03:53 -04:00
flex_array.c reciprocal_divide: update/correction of the algorithm 2014-01-21 23:17:20 -08:00
flex_proportions.c proportions: add @gfp to init functions 2014-09-08 09:51:30 +09:00
gcd.c
…
gen_crc32table.c lib: crc32: constify crc32 lookup table 2015-02-13 21:21:35 -08:00
genalloc.c lib/genalloc.c: check result of devres_alloc() 2015-02-13 21:21:36 -08:00
glob.c lib/glob.c: add CONFIG_GLOB_SELFTEST 2014-08-06 18:01:25 -07:00
halfmd4.c lib/halfmd4.c: simplify includes 2015-02-12 18:54:15 -08:00
hexdump.c hexdump: make it return number of bytes placed in buffer 2015-02-12 18:54:15 -08:00
hweight.c Make ARCH_HAS_FAST_MULTIPLIER a real config variable 2014-09-13 11:14:53 -07:00
idr.c lib/idr.c: remove redundant include 2015-02-12 18:54:15 -08:00
inflate.c
…
int_sqrt.c
…
interval_tree.c lib/interval_tree.c: simplify includes 2015-02-12 18:54:15 -08:00
interval_tree_test.c lib: Export interval_tree 2014-05-05 09:09:14 +02:00
iomap.c Kconfig: rename HAS_IOPORT to HAS_IOPORT_MAP 2014-04-07 16:36:11 -07:00
iomap_copy.c
…
iommu-helper.c
…
ioremap.c x86, mm: support huge KVA mappings on x86 2015-04-14 16:49:04 -07:00
iov_iter.c Merge branch 'iov_iter' into for-next 2015-04-11 22:26:51 -04:00
irq_regs.c
…
is_single_threaded.c
…
jedec_ddr_data.c
…
kasprintf.c
…
kfifo.c kfifo: use BUG_ON 2014-08-08 15:57:25 -07:00
klist.c klist: use same naming scheme as hlist for klist_add_after() 2014-08-06 18:01:24 -07:00
kobject.c kobject: WARN as tip when call kobject_get() to a kobject not initialized 2015-03-25 15:26:49 +01:00
kobject_uevent.c lib/kobject_uevent.c: remove redundant include 2015-02-12 18:54:15 -08:00
kstrtox.c lib/kstrtox.c: remove redundant cleanup 2014-01-23 16:36:57 -08:00
kstrtox.h
…
lcm.c block: fix blk_stack_limits() regression due to lcm() change 2015-03-31 09:45:50 -06:00
libcrc32c.c crypto: LLVMLinux: Remove VLAIS usage from libcrc32c.c 2014-10-14 10:51:23 +02:00
list_debug.c
…
list_sort.c lib/list_sort.c: rearrange includes 2015-02-12 18:54:15 -08:00
llist.c lib/llist.c: remove redundant include 2015-02-12 18:54:15 -08:00
locking-selftest-hardirq.h
…
locking-selftest-mutex.h
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locking-selftest-rlock-hardirq.h
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locking-selftest-rlock-softirq.h
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locking-selftest-rlock.h
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locking-selftest-rsem.h
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locking-selftest-softirq.h
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locking-selftest-spin-hardirq.h
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locking-selftest-spin-softirq.h
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locking-selftest-spin.h
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locking-selftest-wlock-hardirq.h
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locking-selftest-wlock-softirq.h
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locking-selftest-wlock.h
…
locking-selftest-wsem.h
…
locking-selftest.c locking/lockdep: Revert qrwlock recusive stuff 2014-10-03 06:09:30 +02:00
lockref.c locking: Remove ACCESS_ONCE() usage 2015-02-24 08:44:16 +01:00
lru_cache.c lru_cache: remove use of seq_printf return value 2015-04-15 16:35:25 -07:00
md5.c lib/md5.c: simplify include 2015-02-12 18:54:15 -08:00
memory-notifier-error-inject.c
…
memweight.c
…
net_utils.c mac_pton: Use bool not int return 2014-06-25 17:45:43 -07:00
nlattr.c netlink: pad nla_memcpy dest buffer with zeroes 2015-03-31 14:07:24 -04:00
notifier-error-inject.c
…
notifier-error-inject.h
…
of-reconfig-notifier-error-inject.c
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oid_registry.c
…
parser.c lib/parser.c: put EXPORT_SYMBOLs in the conventional place 2014-01-23 16:36:55 -08:00
pci_iomap.c pci: add pci_iomap_range 2015-01-21 16:28:49 +10:30
percpu-refcount.c percpu_ref: make INIT_ATOMIC and switch_to_atomic() sticky 2014-09-24 13:31:50 -04:00
percpu_counter.c percpu_counter: add @gfp to percpu_counter_init() 2014-09-08 09:51:29 +09:00
percpu_ida.c lib/percpu_ida.c: remove redundant includes 2015-02-12 18:54:16 -08:00
percpu_test.c percpu: add test module for various percpu operations 2013-11-13 12:09:11 +09:00
plist.c lib/plist.c: remove redundant include 2015-02-12 18:54:16 -08:00
pm-notifier-error-inject.c
…
proportions.c proportions: add @gfp to init functions 2014-09-08 09:51:30 +09:00
radix-tree.c lib/radix-tree.c: change to simpler include 2015-02-12 18:54:16 -08:00
random32.c random32: improvements to prandom_bytes 2014-08-24 18:36:01 -07:00
ratelimit.c
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rational.c
…
rbtree.c lib/rbtree.c: fix typo in comment of __rb_insert() 2014-08-08 15:57:24 -07:00
rbtree_test.c rbtree/test: test rbtree_postorder_for_each_entry_safe() 2014-01-23 16:37:03 -08:00
reciprocal_div.c reciprocal_divide: update/correction of the algorithm 2014-01-21 23:17:20 -08:00
rhashtable.c rhashtable: provide len to obj_hashfn 2015-03-25 17:18:33 +01:00
scatterlist.c lib/scatterlist: fix memory leak with scsi-mq 2014-10-28 10:27:10 -06:00
seq_buf.c seq_buf: Fix seq_buf_bprintf() truncation 2015-03-04 23:40:19 -05:00
sha1.c lib: EXPORT_SYMBOL sha_init 2015-03-23 22:12:08 -04:00
show_mem.c lib/show_mem.c: remove redundant include 2015-02-12 18:54:16 -08:00
smp_processor_id.c percpu: add preemption checks to __this_cpu ops 2014-04-07 16:36:14 -07:00
sort.c lib/sort.c: move include inside #if 0 2015-02-12 18:54:16 -08:00
stmp_device.c lib/stmp_device.c: replace module.h include 2015-02-12 18:54:16 -08:00
string.c lib: memzero_explicit: use barrier instead of OPTIMIZER_HIDE_VAR 2015-03-20 07:56:12 +11:00
string_helpers.c lib/string_helpers.c: change semantics of string_escape_mem 2015-04-15 16:35:24 -07:00
strncpy_from_user.c lib/strncpy_from_user.c: replace module.h include 2015-02-12 18:54:16 -08:00
strnlen_user.c
…
swiotlb.c swiotlb: don't assume PA 0 is invalid 2014-06-20 16:04:32 -04:00
syscall.c lib/syscall.c: unexport task_current_syscall() 2014-04-03 16:21:06 -07:00
test-hexdump.c lib/test-hexdump.c: fix initconst confusion 2015-04-15 16:35:22 -07:00
test-kstrtox.c lib/test-kstrtox.c: use ARRAY_SIZE instead of sizeof/sizeof[0] 2014-08-06 18:01:25 -07:00
test-string_helpers.c lib/string_helpers.c: change semantics of string_escape_mem 2015-04-15 16:35:24 -07:00
test_bpf.c test: bpf: expand DIV_KX to DIV_MOD_KX 2014-12-08 20:23:22 -05:00
test_firmware.c test: add firmware_class loader test 2014-07-17 18:44:19 -07:00
test_kasan.c lib: add kasan test module 2015-02-13 21:21:41 -08:00
test_module.c test: add minimal module for verification testing 2014-01-23 16:36:57 -08:00
test_rhashtable.c test_rhashtable: Remove bogus max_size setting 2015-04-03 15:09:36 -04:00
test_user_copy.c test: check copy_to/from_user boundary validation 2014-01-23 16:36:57 -08:00
textsearch.c lib/textsearch.c: remove textsearch_put reference from comments 2014-10-14 02:18:14 +02:00
timerqueue.c
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ts_bm.c
…
ts_fsm.c
…
ts_kmp.c
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ucs2_string.c
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usercopy.c
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uuid.c
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vsprintf.c lib/string_helpers.c: change semantics of string_escape_mem 2015-04-15 16:35:24 -07:00