block: recursive merge requests

In a workload, thread 1 accesses a, a+2, ..., thread 2 accesses a+1, a+3,....
When the requests are flushed to queue, a and a+1 are merged to (a, a+1), a+2
and a+3 too to (a+2, a+3), but (a, a+1) and (a+2, a+3) aren't merged.

If we do recursive merge for such interleave access, some workloads throughput
get improvement. A recent worload I'm checking on is swap, below change
boostes the throughput around 5% ~ 10%.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
fs/dyn_sync_cntrl: dynamic sync control

The dynamic sync control interface uses Android kernel's unique early
suspend / lat resume interface.

While screen is on, file sync is disabled
when screen is off, a file sync is called to flush all outstanding writes
and restore file sync operation as normal.

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	fs/sync.c

Conflicts:
	fs/Kconfig
	fs/sync.c
fs/dyn_fsync: check dyn fsync control's active prior to performing fsync ops

Signed-off-by: Andrew Bartholomew <andrewb03@gmail.com>

Conflicts:
	fs/sync.c

Conflicts:
	fs/sync.c
dynamic filesync: add some cache optimizations

and clean up file format and typos

bump version to 1.1

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	fs/sync.c

Conflicts:
	fs/sync.c
dynamic fsync: add reboot notifier to force flush outstanding data

this should further prevent data corruption from kernel panics and
forced reboots

bump version to 1.2

Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	fs/dyn_sync_cntrl.c
dynamic fsync: add kernel panic notifier to force flush outstanding data

more paranoia safety checks

Signed-off-by: Paul Reioux <reioux@gmail.com>
Update defconfig
fs/dcache.c: Fix the too small buffer for dname

temp[64] is used for internal temporary buffer in dynamic_dname().
This is for dname. But It's too small. dname's size may be > 64.
In that case, it returns as -ENAMETOOLONG. So Increase the buffer size
to 256 for avoiding this issue.

The following was caused by the small buffer.
WARNING: at /kernel/mm/page_alloc.c:2470 __alloc_pages_nodemask+0x24c/0x938()
CPU: 2 PID: 505 Comm: android.bg Not tainted 3.10.0-g2f73780-00003-g2ff41d9-dirty #13
[<c010ba3c>] (unwind_backtrace+0x0/0x11c) from [<c0109cac>] (show_stack+0x10/0x14)
[<c0109cac>] (show_stack+0x10/0x14) from [<c01939a0>] (warn_slowpath_common+0x48/0x68)
[<c01939a0>] (warn_slowpath_common+0x48/0x68) from [<c0193a7c>] (warn_slowpath_null+0x18/0x20)
[<c0193a7c>] (warn_slowpath_null+0x18/0x20) from [<c0222454>] (__alloc_pages_nodemask+0x24c/0x938)
[<c0222454>] (__alloc_pages_nodemask+0x24c/0x938) from [<c0222b50>] (__get_free_pages+0x10/0x24)
[<c0222b50>] (__get_free_pages+0x10/0x24) from [<c024faf8>] (kmalloc_order_trace+0x24/0xf0)
[<c024faf8>] (kmalloc_order_trace+0x24/0xf0) from [<c024fe20>] (__kmalloc+0x30/0x244)
[<c024fe20>] (__kmalloc+0x30/0x244) from [<c02723c8>] (seq_read+0x270/0x464)
[<c02723c8>] (seq_read+0x270/0x464) from [<c0256a18>] (vfs_read+0xa4/0x134)
[<c0256a18>] (vfs_read+0xa4/0x134) from [<c0256de8>] (SyS_read+0x38/0x68)
[<c0256de8>] (SyS_read+0x38/0x68) from [<c0106140>] (ret_fast_syscall+0x0/0x30)

Change-Id: I74f5217ba3c4be73e91f33f900f1f0c26810cc05
Signed-off-by: Devin Kim <dojip.kim@lge.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
dynamic fsync: fix build