linux-stable-rt/include
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
..
acpi
asm-generic Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 2011-05-25 17:00:17 -07:00
crypto
drm
keys
linux flex_array: avoid divisions when accessing elements 2011-05-26 17:12:33 -07:00
math-emu
media
mtd
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/linux-2.6-nsfd 2011-05-25 18:10:16 -07:00
pcmcia
rdma Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband 2011-05-26 12:13:57 -07:00
rxrpc
scsi
sound
staging
target
trace Merge branch 'gpio/next' of git://git.secretlab.ca/git/linux-2.6 2011-05-26 12:14:41 -07:00
video
xen Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem 2011-05-26 10:50:56 -07:00
Kbuild