Comment 1 for bug 1336568

After issuing direct I/O from guest instance, dirty cache of control node increases from 0KB to 202436 KB.
This is same size of I/O from guest instance.

[Guest]
[root@driver-test fio]# dd if=/dev/zero of=/dev/vdd oflag=direct bs=1024k count=200
200+0 records in
200+0 records out

[Control node]
[root@control rpmbuild]# cat /proc/meminfo
MemTotal: 8164312 kB
MemFree: 971492 kB
MemAvailable: 3838688 kB
Buffers: 1509816 kB
Cached: 1413724 kB
SwapCached: 37264 kB
Active: 4148700 kB
Inactive: 2574248 kB
Active(anon): 2796988 kB
Inactive(anon): 1016204 kB
Active(file): 1351712 kB
Inactive(file): 1558044 kB
Unevictable: 26172 kB
Mlocked: 26172 kB
SwapTotal: 4079612 kB
SwapFree: 2563736 kB
Dirty: 202436 kB <**************** Cached I/O
Writeback: 0 kB
AnonPages: 3797040 kB
Mapped: 56800 kB
Shmem: 2240 kB
Slab: 269472 kB
SReclaimable: 210844 kB
SUnreclaim: 58628 kB
KernelStack: 5624 kB
PageTables: 68488 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 8161768 kB
Committed_AS: 10106272 kB
VmallocTotal: 34359738367 kB
VmallocUsed: 300076 kB
VmallocChunk: 34359336928 kB
HardwareCorrupted: 0 kB
AnonHugePages: 237568 kB
HugePages_Total: 0
HugePages_Free: 0
HugePages_Rsvd: 0
HugePages_Surp: 0
Hugepagesize: 2048 kB
DirectMap4k: 148068 kB
DirectMap2M: 8230912 kB