Revert "lib/memcopy: use glibc version"

This reverts commit 50f83728ad99dd244405613ee7fc779df77a35d6.
Revert "lib/string: use glibc version"

This reverts commit 5b56a14902fb19591b5b85fd094c38e841060ab1.
Reduce vfs_cache_pressure to 20
ashmem: Fix deadlock when System is low on memory
sched/rt: code cleanup, remove a redundant function call
The second time call to sched_rt_period is redundant, because the value of the
rt_runtime was already read and it was protected by the rurt_runtime_lock.

Signed-off-by: Shan Hai <haishan.bai@gmail.com>
sched: don't call task_group() many times in set_task_rq()
It improves perfomance, especially if autogroup enabled.

The size of set_task_rq() was 0x180 and now it is 0xa0.

Signed-off-by: Andrew Vagin <avagin@openvz.org>
 kernel/timer: Optimise apply_slack() for size and speed.

To apply proper slack, the original algorithm used to prepare a mask and
then apply the mask to obtain the appropriately rounded-off absolute
time the timer expires.

This patch modifies the masking logic to a bit-shift logic, therby
reducing the complexity and number of operations. Thus obtaining a minor
speed-up.
update defconfig again