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linux/lib
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Jesse Gross 704f15ddb5 flex_array: avoid divisions when accessing elements 
On most architectures division is an expensive operation and accessing an
element currently requires four of them.  This performance penalty
effectively precludes flex arrays from being used on any kind of fast
path.  However, two of these divisions can be handled at creation time and
the others can be replaced by a reciprocal divide, completely avoiding
real divisions on access.

[eparis@redhat.com: rebase on top of changes to support 0 len elements]
[eparis@redhat.com: initialize part_nr when array fits entirely in base]
Signed-off-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-26 17:12:33 -07:00
..
lzo lib: add support for LZO-compressed kernels 2010-01-11 09:34:04 -08:00
raid6 Move .gitignore from drivers/md to lib/raid6 2010-08-30 17:35:52 +10:00
reed_solomon
xz XZ decompressor: Fix decoding of empty LZMA2 streams 2011-05-02 08:46:12 -07:00
zlib_deflate zlib: slim down zlib_deflate() workspace when possible 2011-03-22 17:44:17 -07:00
zlib_inflate inflate_fast: sout is already a short so ptr arith was off by one. 2010-03-12 15:52:44 -08:00
.gitignore
argv_split.c tree-wide: convert open calls to remove spaces to skip_spaces() lib function 2009-12-15 08:53:32 -08:00
atomic64_test.c ARM: 6213/1: atomic64_test: add ARM as supported architecture 2010-07-27 10:43:46 +01:00
atomic64.c lib: Fix atomic64_add_unless return value convention 2010-03-01 11:38:46 -08:00
audit.c audit: support the "standard" <asm-generic/unistd.h> 2011-05-04 14:41:28 -04:00
average.c lib: Improve EWMA efficiency by using bitshifts 2010-12-06 15:58:43 -05:00
bcd.c
bch.c lib: add shared BCH ECC library 2011-03-11 14:25:50 +00:00
bitmap.c bitmap, irq: add smp_affinity_list interface to /proc/irq 2011-05-25 08:39:45 -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 Fix common misspellings 2011-03-31 11:26:23 -03:00
bug.c modules: Fix module_bug_list list corruption race 2010-10-05 11:29:27 -07:00
bust_spinlocks.c
check_signature.c
checksum.c lib/checksum: fix one more thinko 2009-11-03 16:06:53 +01:00
cmdline.c
cpu_rmap.c lib: cpu_rmap: CPU affinity reverse-mapping 2011-01-24 14:51:56 -08:00
cpu-notifier-error-inject.c fault-injection: add CPU notifier error injection module 2010-05-27 09:12:48 -07:00
cpumask.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
crc7.c
crc16.c
crc32.c revert "crc32: use __BYTE_ORDER macro for endian detection" 2010-05-26 08:19:23 -07:00
crc32defs.h
crc-ccitt.c
crc-itu-t.c
crc-t10dif.c
ctype.c ctype: constify read-only _ctype string 2009-12-15 08:53:32 -08:00
debug_locks.c Revert "debug_locks: set oops_in_progress if we will log messages." 2010-11-29 15:18:28 -08:00
debugobjects.c debugobjects: Add hint for better object identification 2011-03-08 16:10:38 +01:00
dec_and_lock.c atomic: only take lock when the counter drops to zero on UP as well 2009-06-16 19:47:47 -07:00
decompress_bunzip2.c Decompressors: include <linux/slab.h> in <linux/decompress/mm.h> 2011-01-13 08:03:23 -08:00
decompress_inflate.c decompressors: check input size in decompress_inflate.c 2011-01-13 08:03:25 -08:00
decompress_unlzma.c Decompressors: validate match distance in decompress_unlzma.c 2011-01-13 08:03:24 -08:00
decompress_unlzo.c Decompressors: fix callback-to-callback mode in decompress_unlzo.c 2011-01-13 08:03:24 -08:00
decompress_unxz.c Fix common misspellings 2011-03-31 11:26:23 -03:00
decompress.c decompressors: add boot-time XZ support 2011-01-13 08:03:25 -08:00
devres.c lib/devres.c: fix comment typo 2010-07-11 22:16:32 +02:00
div64.c div64_u64(): improve precision on 32bit platforms 2010-10-26 16:52:19 -07:00
dma-debug.c dma-debug: print information about leaked entry 2011-04-07 16:31:19 +02:00
dump_stack.c
dynamic_debug.c dynamic_debug: add #include <linux/sched.h> 2011-02-03 15:59:58 -08:00
extable.c module: trim exception table on init free. 2009-06-12 21:47:04 +09:30
fault-inject.c headers: remove sched.h from interrupt.h 2009-10-11 11:20:58 -07:00
find_last_bit.c
find_next_bit.c bitops: introduce CONFIG_GENERIC_FIND_BIT_LE 2011-03-23 19:46:14 -07:00
flex_array.c flex_array: avoid divisions when accessing elements 2011-05-26 17:12:33 -07:00
gcd.c lib: add lib/gcd.c 2009-06-18 13:04:05 -07:00
gen_crc32table.c crc32: major optimization 2010-05-25 08:07:06 -07:00
genalloc.c lib/genalloc.c: add support for specifying the physical address 2011-05-25 08:39:54 -07:00
halfmd4.c
hexdump.c include/linux/printk.h lib/hexdump.c: neatening and add CONFIG_PRINTK guard 2011-01-13 08:03:10 -08:00
hweight.c x86: Add optimized popcnt variants 2010-04-06 15:52:11 -07:00
idr.c docbook: add idr/ida to kernel-api docbook 2010-10-26 17:40:56 -07:00
inflate.c MN10300: Don't try and #include <linux/slab.h> in lib/inflate.c from bootloader 2010-08-12 09:51:35 -07:00
int_sqrt.c
iomap_copy.c
iomap.c
iommu-helper.c iommu: inline iommu_num_pages 2010-08-09 20:45:05 -07:00
ioremap.c ACPI, APEI, Generic Hardware Error Source POLL/IRQ/NMI notification type support 2011-01-12 03:06:19 -05:00
irq_regs.c
is_single_threaded.c kernel: is_current_single_threaded: don't use ->mmap_sem 2009-07-17 09:11:31 +10:00
kasprintf.c include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
Kconfig Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into for-linus-1 2011-03-25 17:41:20 +02:00
Kconfig.debug lib: consolidate DEBUG_STACK_USAGE option 2011-05-25 08:39:54 -07:00
Kconfig.kgdb mips,kgdb: kdb low level trap catch and stack trace 2010-05-20 21:04:26 -05:00
Kconfig.kmemcheck kmemcheck: depend on HAVE_ARCH_KMEMCHECK 2009-07-01 22:28:44 +02:00
klist.c
kobject_uevent.c kobject_uevent: fix typo in comments 2010-08-23 18:12:46 -07:00
kobject.c kobject: Introduce kset_find_obj_hinted. 2010-10-22 10:16:44 -07:00
kref.c kref: Add a kref_sub function 2010-11-22 13:25:13 +10:00
kstrtox.c lib: add kstrto*_from_user() 2011-05-25 08:39:52 -07:00
lcm.c block: Fix overrun in lcm() and move it to lib 2010-03-15 12:47:59 +01:00
libcrc32c.c
list_debug.c Expand CONFIG_DEBUG_LIST to several other list operations 2011-02-18 11:32:28 -08:00
list_sort.c lib/list_sort: test: check element addresses 2010-10-26 16:52:19 -07:00
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
lru_cache.c lru_cache: use correct type in sizeof for allocation 2011-05-25 08:39:52 -07:00
Makefile lib: Add generic binary search function to the kernel. 2011-05-19 16:55:27 +09:30
nlattr.c net: fix nla_policy_len to actually _iterate_ over the policy 2011-02-28 12:38:25 -08:00
parser.c Fix common misspellings 2011-03-31 11:26:23 -03:00
percpu_counter.c percpucounter: Optimize __percpu_counter_add a bit through the use of this_cpu() options. 2010-12-17 15:07:18 +01:00
plist.c plist: Add priority list test 2011-03-11 15:14:48 -05:00
prio_heap.c
prio_tree.c
proportions.c
radix-tree.c radix_tree: radix_tree_gang_lookup_tag_slot() may never return 2011-01-26 10:50:04 +10:00
random32.c Merge branch 'master' into for-next 2010-06-16 18:08:13 +02:00
ratelimit.c ratelimit: fix the return value when __ratelimit() fails to acquire the lock 2010-04-07 08:38:04 -07:00
rational.c lib/rational.c needs module.h 2010-01-11 09:34:05 -08:00
rbtree.c Export the augmented rbtree helper functions 2011-01-28 12:16:59 +10:00
reciprocal_div.c
rwsem-spinlock.c rwsem generic spinlock: use IRQ save/restore spinlocks 2010-04-07 16:15:05 -07:00
rwsem.c rwsem: Remove redundant asmregparm annotation 2011-01-27 12:30:40 +01:00
scatterlist.c scatterlist: prevent invalid free when alloc fails 2010-08-30 19:55:09 +02:00
sha1.c
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
sort.c
spinlock_debug.c locking: Further name space cleanups 2009-12-14 23:55:33 +01:00
string_helpers.c
string.c Add a strtobool function matching semantics of existing in kernel equivalents 2011-05-19 16:55:28 +09:30
swiotlb.c swiotlb: fix wrong panic 2011-02-25 15:07:36 -08:00
syscall.c
test-kstrtox.c kstrtox: fix compile warnings in test 2011-04-14 16:06:54 -07:00
textsearch.c textsearch: doc - fix spelling in lib/textsearch.c. 2011-01-24 23:33:30 -08:00
timerqueue.c Fix common misspellings 2011-03-31 11:26:23 -03:00
ts_bm.c
ts_fsm.c
ts_kmp.c
uuid.c Unified UUID/GUID definition 2010-05-19 22:40:47 -04:00
vsprintf.c lib/vsprintf.c: fix interaction of kasprintf() and vsnprintf() when using %pV 2011-05-25 08:39:47 -07:00