Ada anekdot sejarah yang dikenal luas bahwa Tsarina Catherine II menulis sebuah kata Rusia sederhana yang terdiri dari 3 huruf dengan 4 kesalahan. Jauh lebih sedikit diketahui bahwa kesalahan ini sama sekali tidak unik. Anak-anak ekspatriat Eropa yang mempelajari bahasa Rusia dapat dengan mudah menulis kata "landak" dengan dikte sebagai Y-O-Sh-E-G.
, . , “” . , , , . , . , , , , , . Linux .
OpenVz linux kernel maintenance. OpenVz RHEL7 RHEL8. Red Hat 5 , , : , .
memcg accounting. OpenVZ kernel objects — v2.2.x 2001 . , , .
accounting, user beancounters. , . upstream , namespaces cgroups, — , .
memcg accounting Virtuozzo Hybrid Server 7.5, Virtuozzo Hybrid Server 8, , upstream . , , : https://lkml.org/lkml/2021/4/28/70
upstream . , VM Fedora Rawhide - .
memcg per-memcg sysfs memory.kmem.slabinfo. SLAB , memory cgroup, /proc/slabinfo. upstream , . , Fedora — : , .
. , memcg , memory.kmem.slabinfo . , , , drgn tools/cgroup/memcg_slabinfo.py.
crash — . rash , , production node — OOM-killer. ftrace, perf systemtap — .
drgn — . , . , -- - . , -, , , . : https://github.com/osandov/drgn.
, . , out-ouf-tree . drgn .
accounting — . , , . . , upstream — Fedora Rawhide aka fc35. , , — . : drgn .
[root@localhost test]# rpm -q drgn
drgn-0.0.11-2.fc35.x86_64
[root@localhost test]# drgn -s /usr/lib/debug/lib/modules/5.12.0-0.rc8.191.fc35.x86_64/vmlinux
Traceback (most recent call last):
File "/usr/bin/drgn", line 33, in
sys.exit(load_entry_point('drgn==0.0.11', 'console_scripts', 'drgn')())
File "/usr/lib64/python3.9/site-packages/drgn/internal/cli.py", line 119, in main
prog.load_debug_info(args.symbols, **args.default_symbols)
Exception: /usr/lib/debug/usr/lib/modules/5.12.0-0.rc8.191.fc35.x86_64/vmlinux: .debug_info+0x7704ab: unknown DWARF CU version 5
fc34, — .
, , drgn, crash.
!
[root@localhost ~]# crash -d 1 ( dwarf error )
...
Dwarf Error: wrong version in compilation unit header (is 5, should be 2, 3, or 4) [in module /usr/lib/debug/usr/lib/modules/5.11.12-300.fc34.x86_64/vmlinux]
crash: /usr/lib/debug/lib/modules/5.11.12-300.fc34.x86_64/vmlinux: no debugging data available
, :
Fedora 34 gcc 11, debuginfo DWARF version 5. userspace , gdb .
, :
crash gdb, DWARF 5
drgn DWARF 5 ,
systemtap, , .
, Fedor 34 .
-! kernel crashes bug reports? , ?
crash drgn - , DWARF 5 . , - . , . , , , . , Fedora Red Hat CentOS. . , . , .
, Fedora, , - . . :
-, DWARF 4, CONFIG_DEBUG_INFO_DWARF4. , Fedora .
-, , Fedora production , , .
, , , , Open Source.