Mwepụta kernel Linux 5.6

Mgbe ọnwa abụọ nke mmepe gasịrị, Linus Torvalds webatara ntọhapụ kernel Linux 5.6. N'ime mgbanwe ndị a ma ama: ntinye nke WireGuard VPN interface, nkwado maka USB4, oghere aha maka oge, ikike ịmepụta ndị na-ahụ maka nkwụsịtụ TCP site na iji BPF, nkwado mbụ maka MultiPath TCP, na-ewepụ kernel nke nsogbu 2038, usoro "bootconfig" , ZoneFS.

Ụdị ọhụrụ a gụnyere ndozi 13702 sitere na ndị nrụpụta 1810,
patch size - 40 MB (mgbanwe metụtara faịlụ 11577, agbakwunyere ahịrị koodu 610012,
294828 ahịrị wepụrụ). Ihe dị ka 45% nke niile gosipụtara na 5.6
mgbanwe metụtara ndị ọkwọ ụgbọala ngwaọrụ, ihe dịka 15% nke mgbanwe bụ
àgwà maka imelite koodu kpọmkwem maka ụlọ ọrụ ngwaike, 12%
jikọtara ya na nchịkọta netwọkụ, 4% na sistemụ faịlụ yana 3% nke ime
kernel subsystems.

Main ihe ọhụrụ:

• Sistemụ netwọkụ
  • agbakwunyere mmejuputa VPN interface WireGuard, nke a na-emejuputa atumatu dabere na usoro ezoro ezo nke oge a (ChaCha20, Poly1305, Curve25519, BLAKE2s), dị mfe iji, enweghị mgbagwoju anya, egosila onwe ya n'ọtụtụ nnukwu mmejuputa ma na-enye nnukwu arụmọrụ (3,9 ngwa ngwa karịa OpenVPN n'usoro). nke throughput). WireGuard na-eji echiche nke ntụgharị igodo nzuzo, nke gụnyere itinye igodo nzuzo na interface netwọk ọ bụla yana iji ya kechie igodo ọha. A na-agbanwe igodo ọha iji guzobe njikọ n'otu aka ahụ na SSH. Ihe izizi nzuzo achọrọ maka WireGuard ka ọ rụọ ọrụ ọ bụ ebufere site n'ọbá akwụkwọ zinc dị ka akụkụ nke ọkọlọtọ Crypto API na gụnyere n'ime isi 5.5.
  • Amalitere Mwekota nke akụrụngwa dị mkpa iji kwado MPTCP (MultiPath TCP), ndọtị nke TCP protocol maka ịhazi ọrụ nke njikọ TCP na nnyefe nke ngwugwu n'otu oge n'ọtụtụ ụzọ site na netwọk netwọk dị iche iche jikọtara ya na adreesị IP dị iche iche. Maka ngwa netwọkụ, njikọ chịkọtara dị otú ahụ dị ka njikọ TCP oge niile, na mgbagha nkewa niile na-arụ site na MPTCP. Enwere ike iji Multipath TCP na-abawanye mmepụta ma nwekwuo ntụkwasị obi. Dịka ọmụmaatụ, enwere ike iji MPTCP hazie nnyefe data na ekwentị site na iji njikọ WiFi na 4G n'otu oge, ma ọ bụ belata ọnụ ahịa site na ijikọ sava site na iji njikọ dị ọnụ ala karịa otu dị ọnụ.
  • agbakwunyere nkwado maka nhazi usoro nhazi netwọkụ sch_ets (Nhọrọ nnyefe emelitere, IEEE 802.1Qaz), nke na-enye ike ikesa bandwit n'etiti klas dị iche iche nke okporo ụzọ. Ọ bụrụ na ibu dị na otu klaasị okporo ụzọ dị n'okpuru bandwidth ekenyela, mgbe ahụ, ETS na-enye ohere klaasị okporo ụzọ ndị ọzọ iji bandwidth dị (ejighi ya). A haziri Qdisc sch_ets ka ọ bụrụ ọzụzụ PRIO ma na-eji klaasị okporo ụzọ kọwaa oke bandwit siri ike yana nkekọrịta. ETS na-arụ ọrụ dị ka ngwakọta nke ọzụzụ PRIO и DRR - Ọ bụrụ na enwere klaasị okporo ụzọ nwere oke, a na-eji PRIO, mana ọ bụrụ na enweghị okporo ụzọ na kwụ n'ahịrị, ọ na-arụ ọrụ dị ka DRR.
  • Agbakwunyere ụdị mmemme BPF ọhụrụ BPF_PROG_TYPE_STRUCT_OPS, nke na-enye gị ohere imejuputa ndị na-ahụ maka ọrụ kernel site na BPF. Ka ọ dị ugbu a, enwere ike iji njirimara a mejuputa algọridim nke njikwa mkpọchi TCP n'ụdị mmemme BPF. Dị ka ihe atụ chọrọ Mmemme BPF nwere mmejuputa algọridim Ụlọ ọrụ DCTCP.
  • Nabata n'ime isi gbanwee, ngwa ntụgharị asụsụ ethtool ya na ioctl () iji netlink interface. Ọhụrụ interface na-eme ka ọ dịkwuo mfe ịgbakwunye ndọtị, na-emezi njikwa njehie, na-enye ohere izipu ọkwa mgbe mgbanwe steeti, na-eme ka mmekọrịta dị n'etiti kernel na ohere onye ọrụ dị mfe, ma na-ebelata ọnụ ọgụgụ nke ndepụta aha nke kwesịrị ịmekọrịta.
  • agbakwunyere mmejuputa iwu nke FQ-PIE (Flow Queue PIE) netwọọdụ njikwa kwụ n'ahịrị algọridim, nke ezubere ibelata mmetụta na-adịghị mma nke ntinye ngwugwu etiti na akụrụngwa netwọkụ (bufferbloat). FQ-PIE na-egosiputa arụmọrụ dị elu mgbe ejiri ya na sistemụ nwere modem USB.
• Sistemụ Disk, I/O na Sistemụ Faịlụ
  • Maka sistemụ faịlụ Btrfs agbakwunyere mmejuputa asynchronous nke ọrụ DISCARD (na-akara ihe mgbochi ndị a tọhapụrụ na-adịkwaghị mkpa ka echekwa ya n'anụ ahụ). Na mbụ, arụrụ ọrụ DISCARD n'otu n'otu, nke nwere ike ibute mmebi arụmọrụ n'ihi draịva na-echere iwu ndị kwekọrọ ka ọ mechaa. Mmejuputa asynchronous na-enye gị ohere ịghara ichere ka draịva ahụ mezue DISCARD wee rụọ ọrụ a n'azụ.
  • Na XFS rụrụ Na-ehichapụ koodu nke jiri oge ochie 32-bit counter (ụdị time_t dochie time64_t), na-eduga na nsogbu 2038. Njehie edobere na nrụrụ ebe nchekwa mere na nyiwe 32-bit. Emegharịrị koodu ahụ ka ọ rụọ ọrụ na njirimara agbatịkwuru.
  • Sistemụ faịlụ ext4 ewebata Nkwalite arụmọrụ metụtara ijikwa mkpọchi inode n'oge arụ ọrụ ọgụgụ na ide. Emelitere arụmọrụ idegharị n'ụdị Direct I/O. Iji mee ka nchọpụta nsogbu dị mfe, a na-echekwa koodu njehie nke mbụ na nke ikpeazụ na nnukwu ngọngọ.
  • Na sistemụ faịlụ F2FS emejuputa atumatu ike ịchekwa data n'ụdị abịakọrọ. Maka faịlụ ma ọ bụ ndekọ aha onye ọ bụla, enwere ike ịme mkpakọ site na iji iwu "chattr +c file" ma ọ bụ "chattr +c dir; pịa dir/file". Iji mpikota onu dum nkebi, ị nwere ike iji "-o compress_extension=ext" nhọrọ na ugwu utility.
  • kernel gụnyere sistemụ faịlụ Mpaghara, nke na-eme ka ọrụ dị ala dị mfe na ngwaọrụ nchekwa zoned. draịva mpaghara pụtara ngwaọrụ na diski magnetik siri ike ma ọ bụ NVMe SSDs, ebe nchekwa nke kewara n'ime mpaghara mejupụtara otu ngọngọ ma ọ bụ ngalaba, nke a na-ahapụ naanị usoro ntinye data, na-emelite otu ngọngọ niile. Western Digital mepụtara FS ZoneFS wee jikọta mpaghara ọ bụla na draịva ahụ nwere faịlụ dị iche iche nke enwere ike iji chekwaa data na ụdị raw na-enweghị njikwa na ngalaba na ọkwa mgbochi, ya bụ. Na-enye ngwa ohere iji API faịlụ kama ịnweta ngwaọrụ ngọngọ ozugbo iji ioctl.
  • Na NFS, a na-enwe nkwarụ site na ndabara ịrịgo nkebi n'elu UDP. Nkwado agbakwunyere maka ike idetu faịlụ ozugbo n'etiti sava, akọwapụtara na nkọwapụta NFS 4.2. Agbakwunyere nhọrọ ugwu ọhụrụ "softreval", nke na-enye ohere iji ụkpụrụ njirimara cache mee ihe ma ọ bụrụ na ọdịda nkesa. Dịka ọmụmaatụ, mgbe ị na-akọwa nhọrọ a, mgbe ihe nkesa na-adịghị, ọ ga-ekwe omume ịkwaga n'okporo ụzọ dị na akụkụ NFS na ịnweta ozi nke edozila na cache.
  • Rụrụ njikarịcha arụmọrụ nke usoro fs-verity, nke a na-eji nyochaa iguzosi ike n'ezi ihe na nyocha nke faịlụ n'otu n'otu. Ọsọ ịgụ ihe n'usoro n'usoro ekele maka iji osisi hash Merkle. Ewelitela arụmọrụ FS_IOC_ENABLE_VERITY mgbe enweghị data dị na cache (a etinyelarị agụ akwụkwọ nke ibe nwere data).
• Virtualization na Nchekwa
  • Ikike iji gbanyụọ modul SELinux ka ọ na-agba ọsọ akwụsịla, na ibutu SELinux arụgoro arụ ọrụ ga-amachibidoro n'ọdịnihu. Iji gbanyụọ SELinux, ị ga-agafe akara "selinux=0" na ahịrị iwu kernel.
  • agbakwunyere nkwado maka oghere aha maka oge (oghere aha oge), na-enye gị ohere ijikọ ọnọdụ elekere sistemụ na akpa (CLOCK_REALTIME,
    CLOCK_MONOTONIC, CLOCK_BOOTTIME), jiri oge nke gị n'ime akpa ahụ ma, mgbe ị na-ebuga akpa ahụ gaa na onye ọbịa ọzọ, hụ na agụghị CLOCK_MONOTONIC na CLOCK_BOOTTIME adịghị agbanwe agbanwe (tụba n'uche oge mgbe ị wụnyechara, yana ma ọ bụ na-echeghị na ịnọ na ọnọdụ ụra. ).

  • Ewepụla ọdọ mmiri mgbochi /dev/random. Omume / dev/random yiri / dev/urandom n'ihe gbasara igbochi entropy igbochi mgbe mmalite ọdọ mmiri gasịrị.
  • Isi kernel gụnyere onye ọkwọ ụgbọ ala nke na-enye ohere sistemụ ndị ọbịa na-agba ọsọ VirtualBox iji bulie akwụkwọ ndekọ aha nke ndị ọbịa na-ebupụ (VirtualBox Shared Folder).
  • Agbakwunyela otu patches na sistemụ BPF (Onye mgbasa ozi BPF), mgbe ị na-eji usoro Retpoline iji chebe megide mwakpo klaasị Specter V2, ọ na-enye gị ohere ịbawanye arụmọrụ nke ịkpọ mmemme BPF mgbe ihe omume metụtara ha mere (dịka ọmụmaatụ, ọ na-eme ka o kwe omume ịkpọ ndị na-ahụ maka XDP ngwa ngwa mgbe a. ngwugwu netwọk bịarutere).
  • Ọkwọ ụgbọala agbakwunyere iji kwado TEE (Trusted Execution Environment) wuru n'ime AMD APUs.
• Ebe nchekwa na ọrụ sistemụ
  • BPF agbakwunyela nkwado maka ọrụ zuru ụwa ọnụ. A na-eme mmepe dịka akụkụ nke atụmatụ itinye nkwado maka ọba akwụkwọ nke ọrụ enwere ike itinye na mmemme BPF. Nzọụkwụ ọzọ ga-abụ ịkwado mgbatị siri ike nke na-enye ohere ka a na-ebugharị ọrụ zuru ụwa ọnụ, gụnyere dochie ọrụ ụwa dị ugbu a mgbe ha na-arụ ọrụ. Usoro nke BPF na-agbakwụnyekwa nkwado maka ụdị ọrụ maapụ (eji echekwa data na-adịgide adịgide), nke na-akwado ogbugbu na ọnọdụ batch.
  • Agbakwunyere Ngwa “cpu_cooling” na-enye gị ohere ime ka CPU ekpo oke ọkụ dị jụụ site n'itinye ya n'ọnọdụ enweghị ọrụ maka obere oge.
  • Oku sistemu agbakwunyere openat2(), nke na-enye usoro ọkọlọtọ ndị ọzọ iji gbochie mkpebi ụzọ faịlụ (mmachibido ịgafe ebe ugwu, njikọ ihe atụ, njikọ anwansi (/proc/PID/fd), "../" components).
  • Maka sistemu dị iche iche dabere na nnukwu ụlọ. LITTLE, ijikọta cores CPU dị ike na nke na-adịghị arụ ọrụ nke ọma na otu mgbawa, a na-edobe oke uclamp_min mgbe ị na-arụ ọrụ oge.pụtara na kernel 5.3 enwere usoro maka ichekwa ibu). Oke a na-achọpụta na onye nhazi oge ga-etinye ọrụ ahụ na isi CPU nke nwere arụmọrụ zuru oke.
  • A tọhapụrụ kernel ahụ nsogbu nke 2038. Dochiri ndị njikwa ikpeazụ fọdụrụnụ, bụ ndị ji ụdị 32-bit (mbinye aka int) ụdị time_t maka oge oge epochal, nke, na-eburu n'uche akụkọ sitere na 1970, kwesịrị ịfefe na 2038.
  • Na-aga n'ihu na nkwalite nke interface I/O asynchronous io_uring, olee enyere nkwado maka ọrụ ọhụrụ: IORING_OP_FALLOCATE (ndokwa ebe efu), IORING_OP_OPENAT,
    IORING_OP_OPENAT2,
    IORING_OP_CLOSE (faịlụ imeghe na mmechi),
    IORING_OP_FILES_UPDATE (na-agbakwụnye ma wepụ faịlụ na ndepụta nnweta ngwa ngwa),
    IORING_OP_STATX (arịrịọ ozi faịlụ),
    IORING_OP_READ,
    IORING_OP_WRITE (analọgụ dị mfe nke IORING_OP_READV na IORING_OP_WRITEV),
    IORING_OP_FADVISE,
    IORING_OP_MADVISE (ụdị oku dị iche iche nke posix_fadvise na madvise), IORING_OP_SEND,
    IORING_OP_RECV (na-eziga na ịnata data netwọk),
    IORING_OP_EPOLL_CTL (rụ ọrụ na nkọwa faịlụ epoll).

  • Oku sistemu agbakwunyere pidfd_getfd(), na-enye ohere ka usoro weghachite nkọwa faịlụ maka faịlụ mepere emepe site na usoro ọzọ.
  • Emere ya usoro "bootconfig", nke na-enye ohere, na mgbakwunye na nhọrọ ahịrị iwu, iji chọpụta paramita nke kernel site na faịlụ ntọala. Ka ịgbakwunye faịlụ ndị dị otú ahụ na initramfs oyiyi, a na-atụpụta ọrụ bootconfig. Enwere ike iji njirimara a, dịka ọmụmaatụ, hazie kprobes n'oge buut.
  • Emegharịrị usoro maka ichere ide na ịgụ data na ọkpọkọ na-akpọghị aha. Mgbanwe ahụ mere ka o kwe omume ịme ngwa ngwa ọrụ dị ka mgbakọ na-ejikọta nnukwu ọrụ. Agbanyeghị, njikarịcha nwere ike ibute ọnọdụ agbụrụ na GNU n'ihi ahụhụ dị na ntọhapụ 4.2.1, nke edobere na ụdị 4.3.
  • Agbakwunyere ọkọlọtọ PR_SET_IO_FLUSHER na prctl(), nke enwere ike iji mee akara usoro enweghị ebe nchekwa nke na-ekwesịghị ịbụ n'okpuru oke mgbe sistemụ dị ala na ebe nchekwa.
  • Dabere na sistemụ nkesa ebe nchekwa ION ejiri na gam akporo, etinyere sistemu obere ala dma-buf ikpo, nke na-enye gị ohere ijikwa oke nke DMA buffers maka ịkekọrịta ebe nchekwa n'etiti ndị ọkwọ ụgbọala, ngwa na usoro dị iche iche.
• Akụrụngwa architectures
  • Nkwado agbakwunyere maka ndọtị E0PD, nke pụtara na ARMv8.5 ma na-enye ohere maka nchebe megide ọgụ metụtara mmezu nke ntuziaka na CPU. Nchedo dabere na E0PD na-ebute oke elu karịa nchekwa KPTI (Kernel Page Table Isolation).
  • Maka sistemụ dabere na ụkpụrụ ụlọ ARMv8.5, agbakwunyela nkwado maka ntuziaka RNG, na-enye ohere ịnweta ọnụọgụ pseudo-random nọmba ngwaike. N'ime kernel, a na-eji ntuziaka RNG na-emepụta entropy mgbe ị na-ebido kernel-ewepụtara pseudo-random generator.
  • Nkwado ewepụrụ maka MPX (Mgbakwunye Nchekwa Nchekwa) agbakwunyere na kernel 3.19 ma na-enye gị ohere ịhazi nlele nke ihe nrịbama iji hụ na a na-akwanyere ókèala nke ebe nchekwa ugwu. Ejighi teknụzụ a eme ihe n'ọtụtụ ebe na ndị na-achịkọta ma wepụrụ ya na GCC.
  • Maka ihe owuwu RISC-V, nkwado maka KASan (Kernel address sanitizer) emejuputala ngwa nbibi, nke na-enyere aka ịchọpụta njehie mgbe ị na-arụ ọrụ na ebe nchekwa.
• Ngwa
  • Emebere nkwado nkọwapụta USB 4.0, nke dabere na protocol Thunderbolt 3 ma na-enye ntinye aka ruo 40 Gbps, ebe ị na-ejigide ndakọrịta azụ na USB 2.0 na USB 3.2. Site ntụnyere na thunderbolt USB 4.0 interface na-enye gị ohere ịmegharị usoro iwu dị iche iche n'otu eriri nwere njikọ Ụdị-C, gụnyere PCIe, Ngosipụta Port na USB 3.x, yana mmemme ngwanrọ nke ụkpụrụ, dịka ọmụmaatụ, maka ịhazi njikọ netwọk n'etiti ndị ọbịa. Mmejuputa a na-ewuli na onye ọkwọ ụgbọ ala Thunderbolt etinyelarị na kernel Linux wee mee ka ọ rụọ ọrụ na ndị ọbịa na ngwaọrụ USB4 dakọtara. Mgbanwe ndị ahụ na-agbakwụnyekwa nkwado maka Thunderbolt 3 ngwaọrụ na ngwanrọ software nke Njikọ Njikọ, nke na-ahụ maka ịmepụta ọwara maka ijikọ ọtụtụ ngwaọrụ site na otu njikọ.
  • Na amdgpu ọkwọ ụgbọ ala agbakwunyere nkwado mbụ maka HDCP 2.x (Nchedo Ọdịnaya Ọdịnaya Dijitalụ dị elu) teknụzụ nchedo nnomi. Nkwado agbakwunyere maka mgbawa AMD Pollock ASIC dabere na Raven 2. Tinyere ikike ịtọgharịa GPU maka ezinụlọ Renoir na Navi.
  • Onye ọkwọ ụgbọ ala DRM maka kaadị vidiyo Intel agbakwunyere Nkwado DSI VDSC maka ibe nke dabere na Ice Lake na Tiger Lake microarchitecture, LMEM mmap (ebe nchekwa ngwaọrụ mpaghara) emejuputala, emeziwanye VBT (Video BIOS Table) nyocha, nkwado HDCP 2.2 emejuputala maka ibe kọfị kọfị.
  • Ọrụ gara n'ihu na ijikọ koodu ọkwọ ụgbọ ala amdkfd (maka GPU ndị nwere uche, dị ka Fiji, Tonga, Polaris) na onye ọkwọ ụgbọ ala amdgpu.
  • A rụgharịrị onye ọkwọ ụgbọ ala k10temp, na-agbakwunye nkwado maka igosipụta voltaji na paramita ugbu a maka AMD Zen CPUs, yana gbasaa ozi sitere na ihe mmetụta okpomọkụ ejiri na Zen na Zen 2 CPUs.
  • Na onye ọkwọ ụgbọ ala Nouveau agbakwunyere nkwado maka ọnọdụ ntinye ngwa ngwa akwadoro maka NVIDIA GPUs dabere na Turing microarchitecture (GeForce RTX 2000), nke mere ka o kwe omume ịkwado nkwado maka ngwangwa 3D maka kaadị ndị a (nbudata ngwa ngwa gọọmentị nwere mbinye aka dijitalụ NVIDIA chọrọ). Nkwado agbakwunyere maka injin eserese TU10x. E doziela nsogbu dị na HD Audio.
  • Nkwado agbakwunyere maka mkpakọ data mgbe ebufere ya site na DisplayPort MST (Multi-Stream Transport).
  • agbakwunyere ọkwọ ụgbọ ala ọhụrụ"nke 11k»maka ibe ikuku Qualcomm na-akwado 802.11ax.
    Onye ọkwọ ụgbọ ala ahụ dabere na nchịkọta mac80211 ma na-akwado ebe ị ga-enweta, ebe a na-arụ ọrụ na ụdị netwọkụ ntupu.

  • Site na sysfs, a na-enye ohere ịgụ ihe mmetụta okpomọkụ ejiri na draịvụ ike ọgbara ọhụrụ yana SSD.
  • Enyere ya mgbanwe dị ịrịba ama na usoro ụda ALSA, iji wepụ koodu nke nsogbu nke 2038 (na-ezere iji ụdị 32-bit time_t na snd_pcm_mmap_status na snd_pcm_mmap_control interfaces). Nkwado agbakwunyere maka codec ọdịyo ọhụrụ
    Qualcomm WCD9340/WCD9341, Realtek RT700, RT711, RT715, RT1308, Ingenic JZ4770.

  • agbakwunyere Ndị ọkwọ ụgbọ ala maka akụkụ LCD Logic PD 28, Jimax8729d MIPI-DSI, igenic JZ4770, Sony acx424AKP, Leadtek LTK500HD1829, Xinpeng XPP055C272, AUO B116XAK01, GiantPlus940 GPM0
    BOE NV140FHM-N49,
    Satoz SAT050AT40H12R2,
    Nkọ LS020B1DD01D.

  • agbakwunyere nkwado maka bọọdụ ARM na nyiwe Gen1 Amazon Echo (OMAP3630 dabere), Samsung Galaxy S III mini (GT-I8190), Allwinner Emlid Neutis, Libre Computer ALL-H3-IT, PineH64 Model B, Aibretech Amlogic GX PC,
    Armada SolidRun Clearfog GTR, NXPGateworks GW59xx,
    Tolino Shine 3 onye na-agụ ebook,
    Embedded Artists COM (i.MX7ULP), SolidRun Clearfog CX/ITX na HoneyComb (LX2160A), Google Coral Edge TPU (i.MX8MQ),
    Rockchip Radxa Dalang Carrier, Radxa Rock Pi N10, VMRC RK3399Pro SOM
    ST Ericsson HREF520, Inforce 6640, SC7180 IDP, Atmel/Microchip AM9X60 (ARM926 SoC, Kizboxmini), ST stm32mp15, AM3703/AM3715/DM3725, ST Ericsson ab8505, Unisoc SC,9863 Nkwado agbakwunyere maka njikwa PCIe ejiri na Raspberry Pi 7180.

N'otu oge ahụ, Latin American Free Software Foundation kpụrụ
nhọrọ kernel n'efu kpamkpam 5.6 - Linux-liber 5.6-gnu, kpochapụrụ nke ngwa ngwa na ihe ọkwọ ụgbọ ala nwere ihe ndị na-abụghị nke efu ma ọ bụ ngalaba koodu, nke ndị nrụpụta na-ejedebere oke ya. Ntọhapụ ọhụrụ a na-egbochi ịbuba blob na ndị ọkwọ ụgbọala maka AMD TEE, ATH11K na Mediatek SCP. Koodu nhicha blob emelitere na AMD PSP, amdgpu na nouveau ọkwọ ụgbọ ala na sistemụ subsystem.

isi: opennet.ru