David Howells 690d137f44 Reduce the number of expensive division instructions done by _parse_integer() ... _parse_integer() does one or two division instructions (which are slow) per digit parsed to perform the overflow check. Furthermore, these are particularly expensive examples of division instruction as the number of clock cycles required to complete them may go up with the position of the most significant set bit in the dividend: if (*res > div_u64(ULLONG_MAX - val, base)) which is as maximal as possible. Worse, on 32-bit arches, more than one of these division instructions may be required per digit. So, assuming we don't support a base of more than 16, skip the check if the top nibble of the result is not set at this point. Signed-off-by: David Howells <dhowells@redhat.com> [ Changed it to not dereference the pointer all the time - even if the compiler can and does optimize it away, the code just looks cleaner. And edited the top nybble test slightly to make the code generated on x86-64 better in the loop - test against a hoisted constant instead of shifting and testing the result ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2012-02-09 10:09:30 -08:00
..
lzo	…
mpi	lib: Fix 32-bit sparc udiv_qrnnd() definition in mpilib's longlong.h	2012-02-02 10:34:25 +11:00
raid6	md: Add in export.h for files using EXPORT_SYMBOL	2011-10-31 19:31:19 -04:00
reed_solomon	…
xz	XZ: Fix incorrect XZ_BUF_ERROR	2011-09-21 13:39:59 -07:00
zlib_deflate	…
zlib_inflate	…
.gitignore	…
Kconfig	arch: fix ioport mapping on mips,sh	2012-02-07 14:32:24 -08:00
Kconfig.debug	kmemleak: Add support for memory hotplug	2011-12-02 16:12:42 +00:00
Kconfig.kgdb	…
Kconfig.kmemcheck	…
Makefile	lib: Fix multiple definitions of clz_tab	2012-02-02 10:34:23 +11:00
argv_split.c	…
atomic64.c	lib: atomic64: Change the type of local lock to raw_spinlock_t	2011-09-14 13:14:11 +02:00
atomic64_test.c	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
audit.c	…
average.c	…
bcd.c	…
bch.c	…
bitmap.c	lib/bitmap.c: quiet sparse noise about address space	2011-10-31 17:30:56 -07:00
bitrev.c	…
bsearch.c	lib: Add generic binary search function to the kernel.	2011-05-19 16:55:27 +09:30
btree.c	btree: export btree_get_prev() so modules can use btree_for_each	2012-01-10 16:30:49 -08:00
bug.c	bugs, x86: Fix printk levels for panic, softlockups and stack dumps	2012-01-26 21:28:45 +01:00
bust_spinlocks.c	…
check_signature.c	…
checksum.c	lib/checksum.c: optimize do_csum a bit	2011-07-07 04:52:24 -07:00
clz_tab.c	lib: Fix multiple definitions of clz_tab	2012-02-02 10:34:23 +11:00
cmdline.c	…
cordic.c	Docs: wording: functions -> algorithm	2011-10-29 21:20:22 +02:00
cpu-notifier-error-inject.c	…
cpu_rmap.c	…
cpumask.c	cpumask: alloc_cpumask_var() use NUMA_NO_NODE	2011-07-26 16:49:44 -07:00
crc-ccitt.c	…
crc-itu-t.c	…
crc-t10dif.c	…
crc7.c	…
crc8.c	lib: crc8: add new library module providing crc8 algorithm	2011-06-03 15:01:06 -04:00
crc16.c	…
crc32.c	crc32: optimize inner loop	2012-01-10 16:30:51 -08:00
crc32defs.h	…
ctype.c	…
debug_locks.c	…
debugobjects.c	debugobjects: Extend to assert that an object is initialized	2011-11-23 18:49:22 +01:00
dec_and_lock.c	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
decompress.c	…
decompress_bunzip2.c	decompress_bunzip2: remove invalid vi modeline	2011-12-06 10:00:05 +01:00
decompress_inflate.c	…
decompress_unlzma.c	treewide: Fix comment and string typo 'bufer'	2011-12-06 09:53:40 +01:00
decompress_unlzo.c	unlzo: fix input buffer free	2012-01-12 20:13:13 -08:00
decompress_unxz.c	…
devres.c	Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci	2012-01-11 18:50:26 -08:00
digsig.c	lib/digsig: checks for NULL return value	2012-02-02 00:24:04 +11:00
div64.c	…
dma-debug.c	Fix comparison using wrong pointer variable in dma debug code	2011-11-21 11:35:37 +01:00
dump_stack.c	…
dynamic_debug.c	Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core	2011-10-25 12:13:59 +02:00
dynamic_queue_limits.c	dql: Dynamic queue limits	2011-11-29 12:46:19 -05:00
extable.c	…
fault-inject.c	switch debugfs to umode_t	2012-01-03 22:54:56 -05:00
find_last_bit.c	bitops: add #ifndef for each of find bitops	2011-05-26 17:12:38 -07:00
find_next_bit.c	arch: remove CONFIG_GENERIC_FIND_{NEXT_BIT,BIT_LE,LAST_BIT}	2011-05-26 17:12:38 -07:00
flex_array.c	flex_array: avoid divisions when accessing elements	2011-05-26 17:12:33 -07:00
gcd.c	…
gen_crc32table.c	…
genalloc.c	lib, Make gen_pool memory allocator lockless	2011-08-03 11:15:57 -04:00
halfmd4.c	…
hexdump.c	lib: add error checking to hex2bin	2011-09-20 23:24:44 -04:00
hweight.c	…
idr.c	ida: make ida_simple_get/put() IRQ safe	2011-11-02 16:07:00 -07:00
inflate.c	…
int_sqrt.c	…
iomap.c	lib: add GENERIC_PCI_IOMAP	2011-11-28 21:12:42 +02:00
iomap_copy.c	…
iommu-helper.c	…
ioremap.c	…
irq_regs.c	…
is_single_threaded.c	…
kasprintf.c	…
klist.c	…
kobject.c	kobject: remove kset_find_obj_hinted()	2011-12-21 15:13:54 -08:00
kobject_uevent.c	driver-core: skip uevent generation when nobody is listening	2011-12-09 16:23:50 -08:00
kstrtox.c	Reduce the number of expensive division instructions done by _parse_integer()	2012-02-09 10:09:30 -08:00
kstrtox.h	lib/kstrtox: common code between kstrto*() and simple_strto*() functions	2011-10-31 17:30:56 -07:00
lcm.c	lib/lcm.c: quiet sparse noise	2011-07-25 20:57:15 -07:00
libcrc32c.c	…
list_debug.c	…
list_sort.c	…
llist.c	llist: Remove cpu_relax() usage in cmpxchg loops	2011-10-04 12:44:03 +02:00
locking-selftest-hardirq.h	…
locking-selftest-mutex.h	…
locking-selftest-rlock-hardirq.h	…
locking-selftest-rlock-softirq.h	…
locking-selftest-rlock.h	…
locking-selftest-rsem.h	…
locking-selftest-softirq.h	…
locking-selftest-spin-hardirq.h	…
locking-selftest-spin-softirq.h	…
locking-selftest-spin.h	…
locking-selftest-wlock-hardirq.h	…
locking-selftest-wlock-softirq.h	…
locking-selftest-wlock.h	…
locking-selftest-wsem.h	…
locking-selftest.c	rcu: Fix unpaired rcu_irq_enter() from locking selftests	2011-05-26 09:42:19 -07:00
lru_cache.c	lru_cache: use correct type in sizeof for allocation	2011-05-25 08:39:52 -07:00
md5.c	crypto: Move md5_transform to lib/md5.c	2011-08-06 18:32:45 -07:00
nlattr.c	netlink: validate NLA_MSECS length	2011-11-04 17:47:34 -04:00
parser.c	…
pci_iomap.c	lib: add NO_GENERIC_PCI_IOPORT_MAP	2012-01-31 23:19:47 +02:00
percpu_counter.c	lib/percpu_counter.c: enclose hotplug only variables in hotplug ifdef	2011-10-31 17:30:56 -07:00
plist.c	plist: Remove the need to supply locks to plist heads	2011-07-08 14:02:53 +02:00
prio_heap.c	…
prio_tree.c	…
proportions.c	locking, lib/proportions: Annotate prop_local_percpu::lock as raw	2011-09-13 11:11:50 +02:00
radix-tree.c	radix_tree: take radix_tree_path off stack	2012-01-12 20:13:12 -08:00
random32.c	…
ratelimit.c	locking, printk: Annotate logbuf_lock as raw	2011-09-13 11:11:54 +02:00
rational.c	…
rbtree.c	…
reciprocal_div.c	sch_red: Adaptative RED AQM	2011-12-08 19:52:43 -05:00
rwsem-spinlock.c	locking, rwsem: Annotate inner lock as raw	2011-09-13 11:11:59 +02:00
rwsem.c	locking, rwsem: Annotate inner lock as raw	2011-09-13 11:11:59 +02:00
scatterlist.c	…
sha1.c	lib/sha1.c: quiet sparse noise about symbol not declared	2011-09-13 16:09:41 -07:00
show_mem.c	arch, mm: filter disallowed nodes from arch specific show_mem functions	2011-05-25 08:39:03 -07:00
smp_processor_id.c	sched: Wrap scheduler p->cpus_allowed access	2011-10-06 12:46:56 +02:00
sort.c	…
spinlock_debug.c	lib/spinlock_debug.c: print owner on spinlock lockup	2011-10-31 17:30:56 -07:00
string.c	lib/string.c: fix strim() semantics for strings that have only blanks	2011-10-31 17:30:56 -07:00
string_helpers.c	…
swiotlb.c	swiotlb: Expose swiotlb_nr_tlb function to modules	2011-12-06 10:38:03 +00:00
syscall.c	…
test-kstrtox.c	…
textsearch.c	…
timerqueue.c	…
ts_bm.c	…
ts_fsm.c	…
ts_kmp.c	…
uuid.c	…
vsprintf.c	net: introduce and use netdev_features_t for device features sets	2011-11-16 17:43:10 -05:00