From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ... --- Documentation/filesystems/caching/fscache.rst | 348 ++++++++++++++++++++++++++ 1 file changed, 348 insertions(+) create mode 100644 Documentation/filesystems/caching/fscache.rst (limited to 'Documentation/filesystems/caching/fscache.rst') diff --git a/Documentation/filesystems/caching/fscache.rst b/Documentation/filesystems/caching/fscache.rst new file mode 100644 index 000000000..a74d7b052 --- /dev/null +++ b/Documentation/filesystems/caching/fscache.rst @@ -0,0 +1,348 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================== +General Filesystem Caching +========================== + +Overview +======== + +This facility is a general purpose cache for network filesystems, though it +could be used for caching other things such as ISO9660 filesystems too. + +FS-Cache mediates between cache backends (such as CacheFiles) and network +filesystems:: + + +---------+ + | | +--------------+ + | NFS |--+ | | + | | | +-->| CacheFS | + +---------+ | +----------+ | | /dev/hda5 | + | | | | +--------------+ + +---------+ +-------------->| | | + | | +-------+ | |--+ + | AFS |----->| | | FS-Cache | + | | | netfs |-->| |--+ + +---------+ +-->| lib | | | | + | | | | | | +--------------+ + +---------+ | +-------+ +----------+ | | | + | | | +-->| CacheFiles | + | 9P |--+ | /var/cache | + | | +--------------+ + +---------+ + +Or to look at it another way, FS-Cache is a module that provides a caching +facility to a network filesystem such that the cache is transparent to the +user:: + + +---------+ + | | + | Server | + | | + +---------+ + | NETWORK + ~~~~~|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + | + | +----------+ + V | | + +---------+ | | + | | | | + | NFS |----->| FS-Cache | + | | | |--+ + +---------+ | | | +--------------+ +--------------+ + | | | | | | | | + V +----------+ +-->| CacheFiles |-->| Ext3 | + +---------+ | /var/cache | | /dev/sda6 | + | | +--------------+ +--------------+ + | VFS | ^ ^ + | | | | + +---------+ +--------------+ | + | KERNEL SPACE | | + ~~~~~|~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|~~~~~~|~~~~ + | USER SPACE | | + V | | + +---------+ +--------------+ + | | | | + | Process | | cachefilesd | + | | | | + +---------+ +--------------+ + + +FS-Cache does not follow the idea of completely loading every netfs file +opened in its entirety into a cache before permitting it to be accessed and +then serving the pages out of that cache rather than the netfs inode because: + + (1) It must be practical to operate without a cache. + + (2) The size of any accessible file must not be limited to the size of the + cache. + + (3) The combined size of all opened files (this includes mapped libraries) + must not be limited to the size of the cache. + + (4) The user should not be forced to download an entire file just to do a + one-off access of a small portion of it (such as might be done with the + "file" program). + +It instead serves the cache out in chunks as and when requested by the netfs +using it. + + +FS-Cache provides the following facilities: + + * More than one cache can be used at once. Caches can be selected + explicitly by use of tags. + + * Caches can be added / removed at any time, even whilst being accessed. + + * The netfs is provided with an interface that allows either party to + withdraw caching facilities from a file (required for (2)). + + * The interface to the netfs returns as few errors as possible, preferring + rather to let the netfs remain oblivious. + + * There are three types of cookie: cache, volume and data file cookies. + Cache cookies represent the cache as a whole and are not normally visible + to the netfs; the netfs gets a volume cookie to represent a collection of + files (typically something that a netfs would get for a superblock); and + data file cookies are used to cache data (something that would be got for + an inode). + + * Volumes are matched using a key. This is a printable string that is used + to encode all the information that might be needed to distinguish one + superblock, say, from another. This would be a compound of things like + cell name or server address, volume name or share path. It must be a + valid pathname. + + * Cookies are matched using a key. This is a binary blob and is used to + represent the object within a volume (so the volume key need not form + part of the blob). This might include things like an inode number and + uniquifier or a file handle. + + * Cookie resources are set up and pinned by marking the cookie in-use. + This prevents the backing resources from being culled. Timed garbage + collection is employed to eliminate cookies that haven't been used for a + short while, thereby reducing resource overload. This is intended to be + used when a file is opened or closed. + + A cookie can be marked in-use multiple times simultaneously; each mark + must be unused. + + * Begin/end access functions are provided to delay cache withdrawal for the + duration of an operation and prevent structs from being freed whilst + we're looking at them. + + * Data I/O is done by asynchronous DIO to/from a buffer described by the + netfs using an iov_iter. + + * An invalidation facility is available to discard data from the cache and + to deal with I/O that's in progress that is accessing old data. + + * Cookies can be "retired" upon release, thereby causing the object to be + removed from the cache. + + +The netfs API to FS-Cache can be found in: + + Documentation/filesystems/caching/netfs-api.rst + +The cache backend API to FS-Cache can be found in: + + Documentation/filesystems/caching/backend-api.rst + + +Statistical Information +======================= + +If FS-Cache is compiled with the following options enabled:: + + CONFIG_FSCACHE_STATS=y + +then it will gather certain statistics and display them through: + + /proc/fs/fscache/stats + +This shows counts of a number of events that can happen in FS-Cache: + ++--------------+-------+-------------------------------------------------------+ +|CLASS |EVENT |MEANING | ++==============+=======+=======================================================+ +|Cookies |n=N |Number of data storage cookies allocated | ++ +-------+-------------------------------------------------------+ +| |v=N |Number of volume index cookies allocated | ++ +-------+-------------------------------------------------------+ +| |vcol=N |Number of volume index key collisions | ++ +-------+-------------------------------------------------------+ +| |voom=N |Number of OOM events when allocating volume cookies | ++--------------+-------+-------------------------------------------------------+ +|Acquire |n=N |Number of acquire cookie requests seen | ++ +-------+-------------------------------------------------------+ +| |ok=N |Number of acq reqs succeeded | ++ +-------+-------------------------------------------------------+ +| |oom=N |Number of acq reqs failed on ENOMEM | ++--------------+-------+-------------------------------------------------------+ +|LRU |n=N |Number of cookies currently on the LRU | ++ +-------+-------------------------------------------------------+ +| |exp=N |Number of cookies expired off of the LRU | ++ +-------+-------------------------------------------------------+ +| |rmv=N |Number of cookies removed from the LRU | ++ +-------+-------------------------------------------------------+ +| |drp=N |Number of LRU'd cookies relinquished/withdrawn | ++ +-------+-------------------------------------------------------+ +| |at=N |Time till next LRU cull (jiffies) | ++--------------+-------+-------------------------------------------------------+ +|Invals |n=N |Number of invalidations | ++--------------+-------+-------------------------------------------------------+ +|Updates |n=N |Number of update cookie requests seen | ++ +-------+-------------------------------------------------------+ +| |rsz=N |Number of resize requests | ++ +-------+-------------------------------------------------------+ +| |rsn=N |Number of skipped resize requests | ++--------------+-------+-------------------------------------------------------+ +|Relinqs |n=N |Number of relinquish cookie requests seen | ++ +-------+-------------------------------------------------------+ +| |rtr=N |Number of rlq reqs with retire=true | ++ +-------+-------------------------------------------------------+ +| |drop=N |Number of cookies no longer blocking re-acquisition | ++--------------+-------+-------------------------------------------------------+ +|NoSpace |nwr=N |Number of write requests refused due to lack of space | ++ +-------+-------------------------------------------------------+ +| |ncr=N |Number of create requests refused due to lack of space | ++ +-------+-------------------------------------------------------+ +| |cull=N |Number of objects culled to make space | ++--------------+-------+-------------------------------------------------------+ +|IO |rd=N |Number of read operations in the cache | ++ +-------+-------------------------------------------------------+ +| |wr=N |Number of write operations in the cache | ++--------------+-------+-------------------------------------------------------+ + +Netfslib will also add some stats counters of its own. + + +Cache List +========== + +FS-Cache provides a list of cache cookies: + + /proc/fs/fscache/cookies + +This will look something like:: + + # cat /proc/fs/fscache/caches + CACHE REF VOLS OBJS ACCES S NAME + ======== ===== ===== ===== ===== = =============== + 00000001 2 1 2123 1 A default + +where the columns are: + + ======= =============================================================== + COLUMN DESCRIPTION + ======= =============================================================== + CACHE Cache cookie debug ID (also appears in traces) + REF Number of references on the cache cookie + VOLS Number of volumes cookies in this cache + OBJS Number of cache objects in use + ACCES Number of accesses pinning the cache + S State + NAME Name of the cache. + ======= =============================================================== + +The state can be (-) Inactive, (P)reparing, (A)ctive, (E)rror or (W)ithdrawing. + + +Volume List +=========== + +FS-Cache provides a list of volume cookies: + + /proc/fs/fscache/volumes + +This will look something like:: + + VOLUME REF nCOOK ACC FL CACHE KEY + ======== ===== ===== === == =============== ================ + 00000001 55 54 1 00 default afs,example.com,100058 + +where the columns are: + + ======= =============================================================== + COLUMN DESCRIPTION + ======= =============================================================== + VOLUME The volume cookie debug ID (also appears in traces) + REF Number of references on the volume cookie + nCOOK Number of cookies in the volume + ACC Number of accesses pinning the cache + FL Flags on the volume cookie + CACHE Name of the cache or "-" + KEY The indexing key for the volume + ======= =============================================================== + + +Cookie List +=========== + +FS-Cache provides a list of cookies: + + /proc/fs/fscache/cookies + +This will look something like:: + + # head /proc/fs/fscache/cookies + COOKIE VOLUME REF ACT ACC S FL DEF + ======== ======== === === === = == ================ + 00000435 00000001 1 0 -1 - 08 0000000201d080070000000000000000, 0000000000000000 + 00000436 00000001 1 0 -1 - 00 0000005601d080080000000000000000, 0000000000000051 + 00000437 00000001 1 0 -1 - 08 00023b3001d0823f0000000000000000, 0000000000000000 + 00000438 00000001 1 0 -1 - 08 0000005801d0807b0000000000000000, 0000000000000000 + 00000439 00000001 1 0 -1 - 08 00023b3201d080a10000000000000000, 0000000000000000 + 0000043a 00000001 1 0 -1 - 08 00023b3401d080a30000000000000000, 0000000000000000 + 0000043b 00000001 1 0 -1 - 08 00023b3601d080b30000000000000000, 0000000000000000 + 0000043c 00000001 1 0 -1 - 08 00023b3801d080b40000000000000000, 0000000000000000 + +where the columns are: + + ======= =============================================================== + COLUMN DESCRIPTION + ======= =============================================================== + COOKIE The cookie debug ID (also appears in traces) + VOLUME The parent volume cookie debug ID + REF Number of references on the volume cookie + ACT Number of times the cookie is marked for in use + ACC Number of access pins in the cookie + S State of the cookie + FL Flags on the cookie + DEF Key, auxiliary data + ======= =============================================================== + + +Debugging +========= + +If CONFIG_FSCACHE_DEBUG is enabled, the FS-Cache facility can have runtime +debugging enabled by adjusting the value in:: + + /sys/module/fscache/parameters/debug + +This is a bitmask of debugging streams to enable: + + ======= ======= =============================== ======================= + BIT VALUE STREAM POINT + ======= ======= =============================== ======================= + 0 1 Cache management Function entry trace + 1 2 Function exit trace + 2 4 General + 3 8 Cookie management Function entry trace + 4 16 Function exit trace + 5 32 General + 6-8 (Not used) + 9 512 I/O operation management Function entry trace + 10 1024 Function exit trace + 11 2048 General + ======= ======= =============================== ======================= + +The appropriate set of values should be OR'd together and the result written to +the control file. For example:: + + echo $((1|8|512)) >/sys/module/fscache/parameters/debug + +will turn on all function entry debugging. -- cgit v1.2.3