[Devel] review last vz7 patches to port them to vz9

[Vasily Averin]

Kirill, Kostja, Nikita, Pavel,

Please take look at attached vz7 patches to clarify:
should them ported to vz9 or not?

To Pavel:
a0cdc1cf72c4 cgroup/ve: at container start only check virtualizable cgroups
 "proc/mounts: add cursor" related patches, especially  
0aee0dc817d1 proc/mounts: fix skipping mount after cursor
9f4f95d6878e sync: sync_collect_filesystems: fix possible infinite loop

To Nikita:
db80e99e2409 mm: high order allocation detector
0147918f0ec3 ve/posix_timers: adjust CLOCK_BOOTTIME for CT

To Kirill: (FITRIM, ext4, ploop, pfcache?)
27a92eebdab4 ve: Add option allowing ioctl(FITRIM) from inside CT
c76d350fcaf4 fixup for "ve: Add option allowing ioctl(FITRIM) from inside CT"

f198023f31c6 fs/ext4: Make "lazytime" mount option by default
ddc33f38cc64 ext4: Use initial count in ext4_ind_direct_IO()

c15a5ba1b836 ploop: Use preallocation for ext4
dfb578614c41 ploop: Fix leak of discard kreq
004f568630f7 ploop: Track if we have delta with disable_merge
54b4ddbd65f8 ploop: Check disable_merge only if there is a delta with such method
2b8d9cf32c04 ploop: Fix partition refcounter leak
c65cfe6f83d9 ploop: Sanity in kaio_open()

6dc84e083c94 pfcache: Fix unitialized s_csum_partial

To Kostja: (configs, ub, fuse???)

affab14d5490 configs: change the default cpufreq governor to "performance"

2db0f3333215 ub: ub_ratelimit does not initialize ub_ratelimit->lock
cd015897ebd4 ub: correct _ub_get_css() retvalue for dying/stopped containers
    (VvS: it fixes /proc/bc/xxx output, is it still actual for vz9?)

fs/fuse kio: share stucked requests count for prometheus stats
fs/fuse kio: don't use kio with uninitialized statistic
fs/fuse: a typo resulting in corruption of page cache and kernel crash
fs/fuse: released handle could be used in fiemap
fs/fuse: avoid triggering BUG_ON at file close
fuse: illegal access to file in vstorage
fuse/pcs: missing initialization of client role