diff options
Diffstat (limited to 'Documentation/admin-guide')
29 files changed, 1053 insertions, 256 deletions
diff --git a/Documentation/admin-guide/blockdev/index.rst b/Documentation/admin-guide/blockdev/index.rst index b903cf152091..957ccf617797 100644 --- a/Documentation/admin-guide/blockdev/index.rst +++ b/Documentation/admin-guide/blockdev/index.rst @@ -1,8 +1,8 @@ .. SPDX-License-Identifier: GPL-2.0 -=========================== -The Linux RapidIO Subsystem -=========================== +============= +Block Devices +============= .. toctree:: :maxdepth: 1 diff --git a/Documentation/admin-guide/blockdev/zram.rst b/Documentation/admin-guide/blockdev/zram.rst index 54fe63745ed8..c73b16930449 100644 --- a/Documentation/admin-guide/blockdev/zram.rst +++ b/Documentation/admin-guide/blockdev/zram.rst @@ -343,6 +343,11 @@ Admin can request writeback of those idle pages at right timing via:: With the command, zram will writeback idle pages from memory to the storage. +Additionally, if a user choose to writeback only huge and idle pages +this can be accomplished with:: + + echo huge_idle > /sys/block/zramX/writeback + If an admin wants to write a specific page in zram device to the backing device, they could write a page index into the interface. diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst index a1860fc0ca88..d99994345d41 100644 --- a/Documentation/admin-guide/bootconfig.rst +++ b/Documentation/admin-guide/bootconfig.rst @@ -158,9 +158,15 @@ Each key-value pair is shown in each line with following style:: Boot Kernel With a Boot Config ============================== -Since the boot configuration file is loaded with initrd, it will be added -to the end of the initrd (initramfs) image file with padding, size, -checksum and 12-byte magic word as below. +There are two options to boot the kernel with bootconfig: attaching the +bootconfig to the initrd image or embedding it in the kernel itself. + +Attaching a Boot Config to Initrd +--------------------------------- + +Since the boot configuration file is loaded with initrd by default, +it will be added to the end of the initrd (initramfs) image file with +padding, size, checksum and 12-byte magic word as below. [initrd][bootconfig][padding][size(le32)][checksum(le32)][#BOOTCONFIG\n] @@ -196,6 +202,25 @@ To remove the config from the image, you can use -d option as below:: Then add "bootconfig" on the normal kernel command line to tell the kernel to look for the bootconfig at the end of the initrd file. +Embedding a Boot Config into Kernel +----------------------------------- + +If you can not use initrd, you can also embed the bootconfig file in the +kernel by Kconfig options. In this case, you need to recompile the kernel +with the following configs:: + + CONFIG_BOOT_CONFIG_EMBED=y + CONFIG_BOOT_CONFIG_EMBED_FILE="/PATH/TO/BOOTCONFIG/FILE" + +``CONFIG_BOOT_CONFIG_EMBED_FILE`` requires an absolute path or a relative +path to the bootconfig file from source tree or object tree. +The kernel will embed it as the default bootconfig. + +Just as when attaching the bootconfig to the initrd, you need ``bootconfig`` +option on the kernel command line to enable the embedded bootconfig. + +Note that even if you set this option, you can override the embedded +bootconfig by another bootconfig which attached to the initrd. Kernel parameters via Boot Config ================================= diff --git a/Documentation/admin-guide/cgroup-v1/memcg_test.rst b/Documentation/admin-guide/cgroup-v1/memcg_test.rst index 45b94f7b3beb..a402359abb99 100644 --- a/Documentation/admin-guide/cgroup-v1/memcg_test.rst +++ b/Documentation/admin-guide/cgroup-v1/memcg_test.rst @@ -97,7 +97,7 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y. ============= Page Cache is charged at - - add_to_page_cache_locked(). + - filemap_add_folio(). The logic is very clear. (About migration, see below) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 69d7a6983f78..bf842b80bde9 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -184,6 +184,14 @@ cgroup v2 currently supports the following mount options. ignored on non-init namespace mounts. Please refer to the Delegation section for details. + favordynmods + Reduce the latencies of dynamic cgroup modifications such as + task migrations and controller on/offs at the cost of making + hot path operations such as forks and exits more expensive. + The static usage pattern of creating a cgroup, enabling + controllers, and then seeding it with CLONE_INTO_CGROUP is + not affected by this option. + memory_localevents Only populate memory.events with data for the current cgroup, and not any subtrees. This is legacy behaviour, the default @@ -1208,6 +1216,34 @@ PAGE_SIZE multiple when read back. high limit is used and monitored properly, this limit's utility is limited to providing the final safety net. + memory.reclaim + A write-only nested-keyed file which exists for all cgroups. + + This is a simple interface to trigger memory reclaim in the + target cgroup. + + This file accepts a single key, the number of bytes to reclaim. + No nested keys are currently supported. + + Example:: + + echo "1G" > memory.reclaim + + The interface can be later extended with nested keys to + configure the reclaim behavior. For example, specify the + type of memory to reclaim from (anon, file, ..). + + Please note that the kernel can over or under reclaim from + the target cgroup. If less bytes are reclaimed than the + specified amount, -EAGAIN is returned. + + memory.peak + A read-only single value file which exists on non-root + cgroups. + + The max memory usage recorded for the cgroup and its + descendants since the creation of the cgroup. + memory.oom.group A read-write single value file which exists on non-root cgroups. The default value is "0". @@ -1326,6 +1362,12 @@ PAGE_SIZE multiple when read back. Amount of cached filesystem data that is swap-backed, such as tmpfs, shm segments, shared anonymous mmap()s + zswap + Amount of memory consumed by the zswap compression backend. + + zswapped + Amount of application memory swapped out to zswap. + file_mapped Amount of cached filesystem data mapped with mmap() @@ -1516,6 +1558,21 @@ PAGE_SIZE multiple when read back. higher than the limit for an extended period of time. This reduces the impact on the workload and memory management. + memory.zswap.current + A read-only single value file which exists on non-root + cgroups. + + The total amount of memory consumed by the zswap compression + backend. + + memory.zswap.max + A read-write single value file which exists on non-root + cgroups. The default is "max". + + Zswap usage hard limit. If a cgroup's zswap pool reaches this + limit, it will refuse to take any more stores before existing + entries fault back in or are written out to disk. + memory.pressure A read-only nested-keyed file. @@ -1881,7 +1938,7 @@ IO Latency Interface Files io.latency This takes a similar format as the other controllers. - "MAJOR:MINOR target=<target time in microseconds" + "MAJOR:MINOR target=<target time in microseconds>" io.stat If the controller is enabled you will see extra stats in io.stat in diff --git a/Documentation/admin-guide/device-mapper/writecache.rst b/Documentation/admin-guide/device-mapper/writecache.rst index 10429779a91a..60c16b7fd5ac 100644 --- a/Documentation/admin-guide/device-mapper/writecache.rst +++ b/Documentation/admin-guide/device-mapper/writecache.rst @@ -20,6 +20,7 @@ Constructor parameters: size) 5. the number of optional parameters (the parameters with an argument count as two) + start_sector n (default: 0) offset from the start of cache device in 512-byte sectors high_watermark n (default: 50) @@ -74,20 +75,21 @@ Constructor parameters: the origin volume in the last n milliseconds Status: + 1. error indicator - 0 if there was no error, otherwise error number 2. the number of blocks 3. the number of free blocks 4. the number of blocks under writeback -5. the number of read requests -6. the number of read requests that hit the cache -7. the number of write requests -8. the number of write requests that hit uncommitted block -9. the number of write requests that hit committed block -10. the number of write requests that bypass the cache -11. the number of write requests that are allocated in the cache +5. the number of read blocks +6. the number of read blocks that hit the cache +7. the number of write blocks +8. the number of write blocks that hit uncommitted block +9. the number of write blocks that hit committed block +10. the number of write blocks that bypass the cache +11. the number of write blocks that are allocated in the cache 12. the number of write requests that are blocked on the freelist 13. the number of flush requests -14. the number of discard requests +14. the number of discarded blocks Messages: flush diff --git a/Documentation/admin-guide/devices.rst b/Documentation/admin-guide/devices.rst index 035275fedbdd..e3776d77374b 100644 --- a/Documentation/admin-guide/devices.rst +++ b/Documentation/admin-guide/devices.rst @@ -7,10 +7,9 @@ This list is the Linux Device List, the official registry of allocated device numbers and ``/dev`` directory nodes for the Linux operating system. -The LaTeX version of this document is no longer maintained, nor is -the document that used to reside at lanana.org. This version in the -mainline Linux kernel is the master document. Updates shall be sent -as patches to the kernel maintainers (see the +The version of this document at lanana.org is no longer maintained. This +version in the mainline Linux kernel is the master document. Updates +shall be sent as patches to the kernel maintainers (see the :ref:`Documentation/process/submitting-patches.rst <submittingpatches>` document). Specifically explore the sections titled "CHAR and MISC DRIVERS", and "BLOCK LAYER" in the MAINTAINERS file to find the right maintainers diff --git a/Documentation/admin-guide/devices.txt b/Documentation/admin-guide/devices.txt index c07dc0ee860e..9764d6edb189 100644 --- a/Documentation/admin-guide/devices.txt +++ b/Documentation/admin-guide/devices.txt @@ -1933,7 +1933,7 @@ ... 255= /dev/umem/d15p15 15th partition of 16th board. - 117 char COSA/SRP synchronous serial card + 117 char [REMOVED] COSA/SRP synchronous serial card 0 = /dev/cosa0c0 1st board, 1st channel 1 = /dev/cosa0c1 1st board, 2nd channel ... diff --git a/Documentation/admin-guide/efi-stub.rst b/Documentation/admin-guide/efi-stub.rst index 833edb0d0bc4..b24e7c40d832 100644 --- a/Documentation/admin-guide/efi-stub.rst +++ b/Documentation/admin-guide/efi-stub.rst @@ -7,10 +7,10 @@ as a PE/COFF image, thereby convincing EFI firmware loaders to load it as an EFI executable. The code that modifies the bzImage header, along with the EFI-specific entry point that the firmware loader jumps to are collectively known as the "EFI boot stub", and live in -arch/x86/boot/header.S and arch/x86/boot/compressed/eboot.c, +arch/x86/boot/header.S and drivers/firmware/efi/libstub/x86-stub.c, respectively. For ARM the EFI stub is implemented in arch/arm/boot/compressed/efi-header.S and -arch/arm/boot/compressed/efi-stub.c. EFI stub code that is shared +drivers/firmware/efi/libstub/arm32-stub.c. EFI stub code that is shared between architectures is in drivers/firmware/efi/libstub. For arm64, there is no compressed kernel support, so the Image itself diff --git a/Documentation/admin-guide/hw-vuln/index.rst b/Documentation/admin-guide/hw-vuln/index.rst index 8cbc711cda93..4df436e7c417 100644 --- a/Documentation/admin-guide/hw-vuln/index.rst +++ b/Documentation/admin-guide/hw-vuln/index.rst @@ -17,3 +17,4 @@ are configurable at compile, boot or run time. special-register-buffer-data-sampling.rst core-scheduling.rst l1d_flush.rst + processor_mmio_stale_data.rst diff --git a/Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst b/Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst new file mode 100644 index 000000000000..9393c50b5afc --- /dev/null +++ b/Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst @@ -0,0 +1,246 @@ +========================================= +Processor MMIO Stale Data Vulnerabilities +========================================= + +Processor MMIO Stale Data Vulnerabilities are a class of memory-mapped I/O +(MMIO) vulnerabilities that can expose data. The sequences of operations for +exposing data range from simple to very complex. Because most of the +vulnerabilities require the attacker to have access to MMIO, many environments +are not affected. System environments using virtualization where MMIO access is +provided to untrusted guests may need mitigation. These vulnerabilities are +not transient execution attacks. However, these vulnerabilities may propagate +stale data into core fill buffers where the data can subsequently be inferred +by an unmitigated transient execution attack. Mitigation for these +vulnerabilities includes a combination of microcode update and software +changes, depending on the platform and usage model. Some of these mitigations +are similar to those used to mitigate Microarchitectural Data Sampling (MDS) or +those used to mitigate Special Register Buffer Data Sampling (SRBDS). + +Data Propagators +================ +Propagators are operations that result in stale data being copied or moved from +one microarchitectural buffer or register to another. Processor MMIO Stale Data +Vulnerabilities are operations that may result in stale data being directly +read into an architectural, software-visible state or sampled from a buffer or +register. + +Fill Buffer Stale Data Propagator (FBSDP) +----------------------------------------- +Stale data may propagate from fill buffers (FB) into the non-coherent portion +of the uncore on some non-coherent writes. Fill buffer propagation by itself +does not make stale data architecturally visible. Stale data must be propagated +to a location where it is subject to reading or sampling. + +Sideband Stale Data Propagator (SSDP) +------------------------------------- +The sideband stale data propagator (SSDP) is limited to the client (including +Intel Xeon server E3) uncore implementation. The sideband response buffer is +shared by all client cores. For non-coherent reads that go to sideband +destinations, the uncore logic returns 64 bytes of data to the core, including +both requested data and unrequested stale data, from a transaction buffer and +the sideband response buffer. As a result, stale data from the sideband +response and transaction buffers may now reside in a core fill buffer. + +Primary Stale Data Propagator (PSDP) +------------------------------------ +The primary stale data propagator (PSDP) is limited to the client (including +Intel Xeon server E3) uncore implementation. Similar to the sideband response +buffer, the primary response buffer is shared by all client cores. For some +processors, MMIO primary reads will return 64 bytes of data to the core fill +buffer including both requested data and unrequested stale data. This is +similar to the sideband stale data propagator. + +Vulnerabilities +=============== +Device Register Partial Write (DRPW) (CVE-2022-21166) +----------------------------------------------------- +Some endpoint MMIO registers incorrectly handle writes that are smaller than +the register size. Instead of aborting the write or only copying the correct +subset of bytes (for example, 2 bytes for a 2-byte write), more bytes than +specified by the write transaction may be written to the register. On +processors affected by FBSDP, this may expose stale data from the fill buffers +of the core that created the write transaction. + +Shared Buffers Data Sampling (SBDS) (CVE-2022-21125) +---------------------------------------------------- +After propagators may have moved data around the uncore and copied stale data +into client core fill buffers, processors affected by MFBDS can leak data from +the fill buffer. It is limited to the client (including Intel Xeon server E3) +uncore implementation. + +Shared Buffers Data Read (SBDR) (CVE-2022-21123) +------------------------------------------------ +It is similar to Shared Buffer Data Sampling (SBDS) except that the data is +directly read into the architectural software-visible state. It is limited to +the client (including Intel Xeon server E3) uncore implementation. + +Affected Processors +=================== +Not all the CPUs are affected by all the variants. For instance, most +processors for the server market (excluding Intel Xeon E3 processors) are +impacted by only Device Register Partial Write (DRPW). + +Below is the list of affected Intel processors [#f1]_: + + =================== ============ ========= + Common name Family_Model Steppings + =================== ============ ========= + HASWELL_X 06_3FH 2,4 + SKYLAKE_L 06_4EH 3 + BROADWELL_X 06_4FH All + SKYLAKE_X 06_55H 3,4,6,7,11 + BROADWELL_D 06_56H 3,4,5 + SKYLAKE 06_5EH 3 + ICELAKE_X 06_6AH 4,5,6 + ICELAKE_D 06_6CH 1 + ICELAKE_L 06_7EH 5 + ATOM_TREMONT_D 06_86H All + LAKEFIELD 06_8AH 1 + KABYLAKE_L 06_8EH 9 to 12 + ATOM_TREMONT 06_96H 1 + ATOM_TREMONT_L 06_9CH 0 + KABYLAKE 06_9EH 9 to 13 + COMETLAKE 06_A5H 2,3,5 + COMETLAKE_L 06_A6H 0,1 + ROCKETLAKE 06_A7H 1 + =================== ============ ========= + +If a CPU is in the affected processor list, but not affected by a variant, it +is indicated by new bits in MSR IA32_ARCH_CAPABILITIES. As described in a later +section, mitigation largely remains the same for all the variants, i.e. to +clear the CPU fill buffers via VERW instruction. + +New bits in MSRs +================ +Newer processors and microcode update on existing affected processors added new +bits to IA32_ARCH_CAPABILITIES MSR. These bits can be used to enumerate +specific variants of Processor MMIO Stale Data vulnerabilities and mitigation +capability. + +MSR IA32_ARCH_CAPABILITIES +-------------------------- +Bit 13 - SBDR_SSDP_NO - When set, processor is not affected by either the + Shared Buffers Data Read (SBDR) vulnerability or the sideband stale + data propagator (SSDP). +Bit 14 - FBSDP_NO - When set, processor is not affected by the Fill Buffer + Stale Data Propagator (FBSDP). +Bit 15 - PSDP_NO - When set, processor is not affected by Primary Stale Data + Propagator (PSDP). +Bit 17 - FB_CLEAR - When set, VERW instruction will overwrite CPU fill buffer + values as part of MD_CLEAR operations. Processors that do not + enumerate MDS_NO (meaning they are affected by MDS) but that do + enumerate support for both L1D_FLUSH and MD_CLEAR implicitly enumerate + FB_CLEAR as part of their MD_CLEAR support. +Bit 18 - FB_CLEAR_CTRL - Processor supports read and write to MSR + IA32_MCU_OPT_CTRL[FB_CLEAR_DIS]. On such processors, the FB_CLEAR_DIS + bit can be set to cause the VERW instruction to not perform the + FB_CLEAR action. Not all processors that support FB_CLEAR will support + FB_CLEAR_CTRL. + +MSR IA32_MCU_OPT_CTRL +--------------------- +Bit 3 - FB_CLEAR_DIS - When set, VERW instruction does not perform the FB_CLEAR +action. This may be useful to reduce the performance impact of FB_CLEAR in +cases where system software deems it warranted (for example, when performance +is more critical, or the untrusted software has no MMIO access). Note that +FB_CLEAR_DIS has no impact on enumeration (for example, it does not change +FB_CLEAR or MD_CLEAR enumeration) and it may not be supported on all processors +that enumerate FB_CLEAR. + +Mitigation +========== +Like MDS, all variants of Processor MMIO Stale Data vulnerabilities have the +same mitigation strategy to force the CPU to clear the affected buffers before +an attacker can extract the secrets. + +This is achieved by using the otherwise unused and obsolete VERW instruction in +combination with a microcode update. The microcode clears the affected CPU +buffers when the VERW instruction is executed. + +Kernel reuses the MDS function to invoke the buffer clearing: + + mds_clear_cpu_buffers() + +On MDS affected CPUs, the kernel already invokes CPU buffer clear on +kernel/userspace, hypervisor/guest and C-state (idle) transitions. No +additional mitigation is needed on such CPUs. + +For CPUs not affected by MDS or TAA, mitigation is needed only for the attacker +with MMIO capability. Therefore, VERW is not required for kernel/userspace. For +virtualization case, VERW is only needed at VMENTER for a guest with MMIO +capability. + +Mitigation points +----------------- +Return to user space +^^^^^^^^^^^^^^^^^^^^ +Same mitigation as MDS when affected by MDS/TAA, otherwise no mitigation +needed. + +C-State transition +^^^^^^^^^^^^^^^^^^ +Control register writes by CPU during C-state transition can propagate data +from fill buffer to uncore buffers. Execute VERW before C-state transition to +clear CPU fill buffers. + +Guest entry point +^^^^^^^^^^^^^^^^^ +Same mitigation as MDS when processor is also affected by MDS/TAA, otherwise +execute VERW at VMENTER only for MMIO capable guests. On CPUs not affected by +MDS/TAA, guest without MMIO access cannot extract secrets using Processor MMIO +Stale Data vulnerabilities, so there is no need to execute VERW for such guests. + +Mitigation control on the kernel command line +--------------------------------------------- +The kernel command line allows to control the Processor MMIO Stale Data +mitigations at boot time with the option "mmio_stale_data=". The valid +arguments for this option are: + + ========== ================================================================= + full If the CPU is vulnerable, enable mitigation; CPU buffer clearing + on exit to userspace and when entering a VM. Idle transitions are + protected as well. It does not automatically disable SMT. + full,nosmt Same as full, with SMT disabled on vulnerable CPUs. This is the + complete mitigation. + off Disables mitigation completely. + ========== ================================================================= + +If the CPU is affected and mmio_stale_data=off is not supplied on the kernel +command line, then the kernel selects the appropriate mitigation. + +Mitigation status information +----------------------------- +The Linux kernel provides a sysfs interface to enumerate the current +vulnerability status of the system: whether the system is vulnerable, and +which mitigations are active. The relevant sysfs file is: + + /sys/devices/system/cpu/vulnerabilities/mmio_stale_data + +The possible values in this file are: + + .. list-table:: + + * - 'Not affected' + - The processor is not vulnerable + * - 'Vulnerable' + - The processor is vulnerable, but no mitigation enabled + * - 'Vulnerable: Clear CPU buffers attempted, no microcode' + - The processor is vulnerable, but microcode is not updated. The + mitigation is enabled on a best effort basis. + * - 'Mitigation: Clear CPU buffers' + - The processor is vulnerable and the CPU buffer clearing mitigation is + enabled. + +If the processor is vulnerable then the following information is appended to +the above information: + + ======================== =========================================== + 'SMT vulnerable' SMT is enabled + 'SMT disabled' SMT is disabled + 'SMT Host state unknown' Kernel runs in a VM, Host SMT state unknown + ======================== =========================================== + +References +---------- +.. [#f1] Affected Processors + https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html diff --git a/Documentation/admin-guide/kernel-parameters.rst b/Documentation/admin-guide/kernel-parameters.rst index 01ba293a2d70..959f73a32712 100644 --- a/Documentation/admin-guide/kernel-parameters.rst +++ b/Documentation/admin-guide/kernel-parameters.rst @@ -99,6 +99,7 @@ parameter is applicable:: ALSA ALSA sound support is enabled. APIC APIC support is enabled. APM Advanced Power Management support is enabled. + APPARMOR AppArmor support is enabled. ARM ARM architecture is enabled. ARM64 ARM64 architecture is enabled. AX25 Appropriate AX.25 support is enabled. @@ -108,15 +109,15 @@ parameter is applicable:: DYNAMIC_DEBUG Build in debug messages and enable them at runtime EDD BIOS Enhanced Disk Drive Services (EDD) is enabled EFI EFI Partitioning (GPT) is enabled - EIDE EIDE/ATAPI support is enabled. EVM Extended Verification Module FB The frame buffer device is enabled. FTRACE Function tracing enabled. GCOV GCOV profiling is enabled. + HIBERNATION HIBERNATION is enabled. HW Appropriate hardware is enabled. + HYPER_V HYPERV support is enabled. IA-64 IA-64 architecture is enabled. IMA Integrity measurement architecture is enabled. - IOSCHED More than one I/O scheduler is enabled. IP_PNP IP DHCP, BOOTP, or RARP is enabled. IPV6 IPv6 support is enabled. ISAPNP ISA PnP code is enabled. @@ -140,7 +141,6 @@ parameter is applicable:: NUMA NUMA support is enabled. NFS Appropriate NFS support is enabled. OF Devicetree is enabled. - OSS OSS sound support is enabled. PV_OPS A paravirtualized kernel is enabled. PARIDE The ParIDE (parallel port IDE) subsystem is enabled. PARISC The PA-RISC architecture is enabled. @@ -160,7 +160,6 @@ parameter is applicable:: the Documentation/scsi/ sub-directory. SECURITY Different security models are enabled. SELINUX SELinux support is enabled. - APPARMOR AppArmor support is enabled. SERIAL Serial support is enabled. SH SuperH architecture is enabled. SMP The kernel is an SMP kernel. @@ -168,7 +167,6 @@ parameter is applicable:: SWSUSP Software suspend (hibernation) is enabled. SUSPEND System suspend states are enabled. TPM TPM drivers are enabled. - TS Appropriate touchscreen support is enabled. UMS USB Mass Storage support is enabled. USB USB support is enabled. USBHID USB Human Interface Device support is enabled. @@ -177,7 +175,6 @@ parameter is applicable:: VGA The VGA console has been enabled. VT Virtual terminal support is enabled. WDT Watchdog support is enabled. - XT IBM PC/XT MFM hard disk support is enabled. X86-32 X86-32, aka i386 architecture is enabled. X86-64 X86-64 architecture is enabled. More X86-64 boot options can be found in @@ -211,7 +208,7 @@ The number of kernel parameters is not limited, but the length of the complete command line (parameters including spaces etc.) is limited to a fixed number of characters. This limit depends on the architecture and is between 256 and 4096 characters. It is defined in the file -./include/asm/setup.h as COMMAND_LINE_SIZE. +./include/uapi/asm-generic/setup.h as COMMAND_LINE_SIZE. Finally, the [KMG] suffix is commonly described after a number of kernel parameter values. These 'K', 'M', and 'G' letters represent the _binary_ diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 2d67cdfbf9c9..ef9f80b1ddde 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -400,6 +400,12 @@ arm64.nomte [ARM64] Unconditionally disable Memory Tagging Extension support + arm64.nosve [ARM64] Unconditionally disable Scalable Vector + Extension support + + arm64.nosme [ARM64] Unconditionally disable Scalable Matrix + Extension support + ataflop= [HW,M68k] atarimouse= [HW,MOUSE] Atari Mouse @@ -461,6 +467,12 @@ Format: <io>,<irq>,<mode> See header of drivers/net/hamradio/baycom_ser_hdx.c. + bert_disable [ACPI] + Disable BERT OS support on buggy BIOSes. + + bgrt_disable [ACPI][X86] + Disable BGRT to avoid flickering OEM logo. + blkdevparts= Manual partition parsing of block device(s) for embedded devices based on command line input. See Documentation/block/cmdline-partition.rst @@ -476,12 +488,6 @@ See Documentation/admin-guide/bootconfig.rst - bert_disable [ACPI] - Disable BERT OS support on buggy BIOSes. - - bgrt_disable [ACPI][X86] - Disable BGRT to avoid flickering OEM logo. - bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) bttv.radio= Most important insmod options are available as kernel args too. @@ -550,7 +556,7 @@ nosocket -- Disable socket memory accounting. nokmem -- Disable kernel memory accounting. - checkreqprot [SELINUX] Set initial checkreqprot flag value. + checkreqprot= [SELINUX] Set initial checkreqprot flag value. Format: { "0" | "1" } See security/selinux/Kconfig help text. 0 -- check protection applied by kernel (includes @@ -563,6 +569,25 @@ cio_ignore= [S390] See Documentation/s390/common_io.rst for details. + + clearcpuid=X[,X...] [X86] + Disable CPUID feature X for the kernel. See + arch/x86/include/asm/cpufeatures.h for the valid bit + numbers X. Note the Linux-specific bits are not necessarily + stable over kernel options, but the vendor-specific + ones should be. + X can also be a string as appearing in the flags: line + in /proc/cpuinfo which does not have the above + instability issue. However, not all features have names + in /proc/cpuinfo. + Note that using this option will taint your kernel. + Also note that user programs calling CPUID directly + or using the feature without checking anything + will still see it. This just prevents it from + being used by the kernel or shown in /proc/cpuinfo. + Also note the kernel might malfunction if you disable + some critical bits. + clk_ignore_unused [CLK] Prevents the clock framework from automatically gating @@ -631,24 +656,6 @@ Defaults to zero when built as a module and to 10 seconds when built into the kernel. - clearcpuid=X[,X...] [X86] - Disable CPUID feature X for the kernel. See - arch/x86/include/asm/cpufeatures.h for the valid bit - numbers X. Note the Linux-specific bits are not necessarily - stable over kernel options, but the vendor-specific - ones should be. - X can also be a string as appearing in the flags: line - in /proc/cpuinfo which does not have the above - instability issue. However, not all features have names - in /proc/cpuinfo. - Note that using this option will taint your kernel. - Also note that user programs calling CPUID directly - or using the feature without checking anything - will still see it. This just prevents it from - being used by the kernel or shown in /proc/cpuinfo. - Also note the kernel might malfunction if you disable - some critical bits. - cma=nn[MG]@[start[MG][-end[MG]]] [KNL,CMA] Sets the size of kernel global memory area for @@ -770,6 +777,24 @@ 0: default value, disable debugging 1: enable debugging at boot time + cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver + Format: + <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] + + cpu0_hotplug [X86] Turn on CPU0 hotplug feature when + CONFIG_BOOTPARAM_HOTPLUG_CPU0 is off. + Some features depend on CPU0. Known dependencies are: + 1. Resume from suspend/hibernate depends on CPU0. + Suspend/hibernate will fail if CPU0 is offline and you + need to online CPU0 before suspend/hibernate. + 2. PIC interrupts also depend on CPU0. CPU0 can't be + removed if a PIC interrupt is detected. + It's said poweroff/reboot may depend on CPU0 on some + machines although I haven't seen such issues so far + after CPU0 is offline on a few tested machines. + If the dependencies are under your control, you can + turn on cpu0_hotplug. + cpuidle.off=1 [CPU_IDLE] disable the cpuidle sub-system @@ -790,9 +815,13 @@ on every CPU online, such as boot, and resume from suspend. Default: 10000 - cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver - Format: - <first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>] + crash_kexec_post_notifiers + Run kdump after running panic-notifiers and dumping + kmsg. This only for the users who doubt kdump always + succeeds in any situation. + Note that this also increases risks of kdump failure, + because some panic notifiers can make the crashed + kernel more unstable. crashkernel=size[KMG][@offset[KMG]] [KNL] Using kexec, Linux can switch to a 'crash kernel' @@ -956,11 +985,15 @@ [KNL] Debugging option to set a timeout in seconds for deferred probe to give up waiting on dependencies to probe. Only specific dependencies (subsystems or - drivers) that have opted in will be ignored. A timeout of 0 - will timeout at the end of initcalls. This option will also + drivers) that have opted in will be ignored. A timeout + of 0 will timeout at the end of initcalls. If the time + out hasn't expired, it'll be restarted by each + successful driver registration. This option will also dump out devices still on the deferred probe list after retrying. + delayacct [KNL] Enable per-task delay accounting + dell_smm_hwmon.ignore_dmi= [HW] Continue probing hardware even if DMI data indicates that the driver is running on unsupported @@ -1014,17 +1047,6 @@ disable= [IPV6] See Documentation/networking/ipv6.rst. - hardened_usercopy= - [KNL] Under CONFIG_HARDENED_USERCOPY, whether - hardening is enabled for this boot. Hardened - usercopy checking is used to protect the kernel - from reading or writing beyond known memory - allocation boundaries as a proactive defense - against bounds-checking flaws in the kernel's - copy_to_user()/copy_from_user() interface. - on Perform hardened usercopy checks (default). - off Disable hardened usercopy checks. - disable_radix [PPC] Disable RADIX MMU mode on POWER9 @@ -1087,7 +1109,10 @@ driver later using sysfs. driver_async_probe= [KNL] - List of driver names to be probed asynchronously. + List of driver names to be probed asynchronously. * + matches with all driver names. If * is specified, the + rest of the listed driver names are those that will NOT + match the *. Format: <driver_name1>,<driver_name2>... drm.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>] @@ -1293,7 +1318,7 @@ Append ",keep" to not disable it when the real console takes over. - Only one of vga, efi, serial, or usb debug port can + Only one of vga, serial, or usb debug port can be used at a time. Currently only ttyS0 and ttyS1 may be specified by @@ -1308,7 +1333,7 @@ Interaction with the standard serial driver is not very good. - The VGA and EFI output is eventually overwritten by + The VGA output is eventually overwritten by the real console. The xen option can only be used in Xen domains. @@ -1327,17 +1352,6 @@ force: enforce the use of EDAC to report H/W event. default: on. - ekgdboc= [X86,KGDB] Allow early kernel console debugging - ekgdboc=kbd - - This is designed to be used in conjunction with - the boot argument: earlyprintk=vga - - This parameter works in place of the kgdboc parameter - but can only be used if the backing tty is available - very early in the boot process. For early debugging - via a serial port see kgdboc_earlycon instead. - edd= [EDD] Format: {"off" | "on" | "skip[mbr]"} @@ -1399,6 +1413,17 @@ eisa_irq_edge= [PARISC,HW] See header of drivers/parisc/eisa.c. + ekgdboc= [X86,KGDB] Allow early kernel console debugging + Format: ekgdboc=kbd + + This is designed to be used in conjunction with + the boot argument: earlyprintk=vga + + This parameter works in place of the kgdboc parameter + but can only be used if the backing tty is available + very early in the boot process. For early debugging + via a serial port see kgdboc_earlycon instead. + elanfreq= [X86-32] See comment before function elanfreq_setup() in arch/x86/kernel/cpu/cpufreq/elanfreq.c. @@ -1420,7 +1445,7 @@ (in particular on some ATI chipsets). The kernel tries to set a reasonable default. - enforcing [SELINUX] Set initial enforcing status. + enforcing= [SELINUX] Set initial enforcing status. Format: {"0" | "1"} See security/selinux/Kconfig help text. 0 -- permissive (log only, no denials). @@ -1597,6 +1622,17 @@ Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0. Default: 1024 + hardened_usercopy= + [KNL] Under CONFIG_HARDENED_USERCOPY, whether + hardening is enabled for this boot. Hardened + usercopy checking is used to protect the kernel + from reading or writing beyond known memory + allocation boundaries as a proactive defense + against bounds-checking flaws in the kernel's + copy_to_user()/copy_from_user() interface. + on Perform hardened usercopy checks (default). + off Disable hardened usercopy checks. + hardlockup_all_cpu_backtrace= [KNL] Should the hard-lockup detector generate backtraces on all cpus. @@ -1617,6 +1653,15 @@ corresponding firmware-first mode error processing logic will be disabled. + hibernate= [HIBERNATION] + noresume Don't check if there's a hibernation image + present during boot. + nocompress Don't compress/decompress hibernation images. + no Disable hibernation and resume. + protect_image Turn on image protection during restoration + (that will set all pages holding image data + during restoration read-only). + highmem=nn[KMG] [KNL,BOOT] forces the highmem zone to have an exact size of <nn>. This works even on boxes that have no highmem otherwise. This also works to reduce highmem @@ -1639,16 +1684,6 @@ hpet_mmap= [X86, HPET_MMAP] Allow userspace to mmap HPET registers. Default set by CONFIG_HPET_MMAP_DEFAULT. - hugetlb_cma= [HW,CMA] The size of a CMA area used for allocation - of gigantic hugepages. Or using node format, the size - of a CMA area per node can be specified. - Format: nn[KMGTPE] or (node format) - <node>:nn[KMGTPE][,<node>:nn[KMGTPE]] - - Reserve a CMA area of given size and allocate gigantic - hugepages using the CMA allocator. If enabled, the - boot-time allocation of gigantic hugepages is skipped. - hugepages= [HW] Number of HugeTLB pages to allocate at boot. If this follows hugepagesz (below), it specifies the number of pages of hugepagesz to be allocated. @@ -1670,17 +1705,27 @@ Documentation/admin-guide/mm/hugetlbpage.rst. Format: size[KMG] + hugetlb_cma= [HW,CMA] The size of a CMA area used for allocation + of gigantic hugepages. Or using node format, the size + of a CMA area per node can be specified. + Format: nn[KMGTPE] or (node format) + <node>:nn[KMGTPE][,<node>:nn[KMGTPE]] + + Reserve a CMA area of given size and allocate gigantic + hugepages using the CMA allocator. If enabled, the + boot-time allocation of gigantic hugepages is skipped. + hugetlb_free_vmemmap= - [KNL] Reguires CONFIG_HUGETLB_PAGE_FREE_VMEMMAP + [KNL] Reguires CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP enabled. Allows heavy hugetlb users to free up some more memory (7 * PAGE_SIZE for each 2MB hugetlb page). - Format: { on | off (default) } + Format: { [oO][Nn]/Y/y/1 | [oO][Ff]/N/n/0 (default) } - on: enable the feature - off: disable the feature + [oO][Nn]/Y/y/1: enable the feature + [oO][Ff]/N/n/0: disable the feature - Built with CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON=y, + Built with CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON=y, the default is on. This is not compatible with memory_hotplug.memmap_on_memory. @@ -1769,26 +1814,6 @@ icn= [HW,ISDN] Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] - ide-core.nodma= [HW] (E)IDE subsystem - Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc - .vlb_clock .pci_clock .noflush .nohpa .noprobe .nowerr - .cdrom .chs .ignore_cable are additional options - See Documentation/ide/ide.rst. - - ide-generic.probe-mask= [HW] (E)IDE subsystem - Format: <int> - Probe mask for legacy ISA IDE ports. Depending on - platform up to 6 ports are supported, enabled by - setting corresponding bits in the mask to 1. The - default value is 0x0, which has a special meaning. - On systems that have PCI, it triggers scanning the - PCI bus for the first and the second port, which - are then probed. On systems without PCI the value - of 0x0 enables probing the two first ports as if it - was 0x3. - - ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem - Claim all unknown PCI IDE storage controllers. idle= [X86] Format: idle=poll, idle=halt, idle=nomwait @@ -2399,8 +2424,7 @@ the KVM_CLEAR_DIRTY ioctl, and only for the pages being cleared. - Eager page splitting currently only supports splitting - huge pages mapped by the TDP MMU. + Eager page splitting is only supported when kvm.tdp_mmu=Y. Default is Y (on). @@ -2450,7 +2474,6 @@ protected: nVHE-based mode with support for guests whose state is kept private from the host. - Not valid if the kernel is running in EL2. Defaults to VHE/nVHE based on hardware support. Setting mode to "protected" will disable kexec and hibernation @@ -2722,8 +2745,6 @@ If there are multiple matching configurations changing the same attribute, the last one is used. - memblock=debug [KNL] Enable memblock debug messages. - load_ramdisk= [RAM] [Deprecated] lockd.nlm_grace_period=P [NFS] Assign grace period. @@ -2865,7 +2886,7 @@ different yeeloong laptops. Example: machtype=lemote-yeeloong-2f-7inch - max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater + max_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory greater than or equal to this physical address is ignored. maxcpus= [SMP] Maximum number of processors that an SMP kernel @@ -2965,6 +2986,8 @@ mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel memory. + memblock=debug [KNL] Enable memblock debug messages. + memchunk=nn[KMG] [KNL,SH] Allow user to override the default size for per-device physically contiguous DMA buffers. @@ -3085,7 +3108,7 @@ mem_encrypt=on: Activate SME mem_encrypt=off: Do not activate SME - Refer to Documentation/virt/kvm/amd-memory-encryption.rst + Refer to Documentation/virt/kvm/x86/amd-memory-encryption.rst for details on when memory encryption can be activated. mem_sleep_default= [SUSPEND] Default system suspend mode: @@ -3108,7 +3131,7 @@ mga= [HW,DRM] - min_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory below this + min_addr=nn[KMG] [KNL,BOOT,IA-64] All physical memory below this physical address is ignored. mini2440= [ARM,HW,KNL] @@ -3143,7 +3166,7 @@ improves system performance, but it may also expose users to several CPU vulnerabilities. Equivalent to: nopti [X86,PPC] - kpti=0 [ARM64] + if nokaslr then kpti=0 [ARM64] nospectre_v1 [X86,PPC] nobp=0 [S390] nospectre_v2 [X86,PPC,S390,ARM64] @@ -3157,6 +3180,8 @@ srbds=off [X86,INTEL] no_entry_flush [PPC] no_uaccess_flush [PPC] + mmio_stale_data=off [X86] + retbleed=off [X86] Exceptions: This does not have any effect on @@ -3178,6 +3203,8 @@ Equivalent to: l1tf=flush,nosmt [X86] mds=full,nosmt [X86] tsx_async_abort=full,nosmt [X86] + mmio_stale_data=full,nosmt [X86] + retbleed=auto,nosmt [X86] mminit_loglevel= [KNL] When CONFIG_DEBUG_MEMORY_INIT is set, this @@ -3187,6 +3214,40 @@ log everything. Information is printed at KERN_DEBUG so loglevel=8 may also need to be specified. + mmio_stale_data= + [X86,INTEL] Control mitigation for the Processor + MMIO Stale Data vulnerabilities. + + Processor MMIO Stale Data is a class of + vulnerabilities that may expose data after an MMIO + operation. Exposed data could originate or end in + the same CPU buffers as affected by MDS and TAA. + Therefore, similar to MDS and TAA, the mitigation + is to clear the affected CPU buffers. + + This parameter controls the mitigation. The + options are: + + full - Enable mitigation on vulnerable CPUs + + full,nosmt - Enable mitigation and disable SMT on + vulnerable CPUs. + + off - Unconditionally disable mitigation + + On MDS or TAA affected machines, + mmio_stale_data=off can be prevented by an active + MDS or TAA mitigation as these vulnerabilities are + mitigated with the same mechanism so in order to + disable this mitigation, you need to specify + mds=off and tsx_async_abort=off too. + + Not specifying this option is equivalent to + mmio_stale_data=full. + + For details see: + Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst + module.sig_enforce [KNL] When CONFIG_MODULE_SIG is set, this means that modules without (valid) signatures will fail to load. @@ -3233,20 +3294,6 @@ mtdparts= [MTD] See drivers/mtd/parsers/cmdlinepart.c - multitce=off [PPC] This parameter disables the use of the pSeries - firmware feature for updating multiple TCE entries - at a time. - - onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration - - Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock] - - boundary - index of last SLC block on Flex-OneNAND. - The remaining blocks are configured as MLC blocks. - lock - Configure if Flex-OneNAND boundary should be locked. - Once locked, the boundary cannot be changed. - 1 indicates lock status, 0 indicates unlock status. - mtdset= [ARM] ARM/S3C2412 JIVE boot control @@ -3273,6 +3320,10 @@ Used for mtrr cleanup. It is spare mtrr entries number. Set to 2 or more if your graphical card needs more. + multitce=off [PPC] This parameter disables the use of the pSeries + firmware feature for updating multiple TCE entries + at a time. + n2= [NET] SDL Inc. RISCom/N2 synchronous serial card netdev= [NET] Network devices parameters @@ -3282,6 +3333,11 @@ This usage is only documented in each driver source file if at all. + netpoll.carrier_timeout= + [NET] Specifies amount of time (in seconds) that + netpoll should wait for a carrier. By default netpoll + waits 4 seconds. + nf_conntrack.acct= [NETFILTER] Enable connection tracking flow accounting 0 to disable accounting @@ -3432,11 +3488,6 @@ These settings can be accessed at runtime via the nmi_watchdog and hardlockup_panic sysctls. - netpoll.carrier_timeout= - [NET] Specifies amount of time (in seconds) that - netpoll should wait for a carrier. By default netpoll - waits 4 seconds. - no387 [BUGS=X86-32] Tells the kernel to use the 387 maths emulation library even if a 387 maths coprocessor is present. @@ -3491,8 +3542,6 @@ nocache [ARM] - delayacct [KNL] Enable per-task delay accounting - nodsp [SH] Disable hardware DSP at boot time. noefi Disable EFI runtime services support. @@ -3617,6 +3666,9 @@ just as if they had also been called out in the rcu_nocbs= boot parameter. + Note that this argument takes precedence over + the CONFIG_RCU_NOCB_CPU_DEFAULT_ALL option. + noiotrap [SH] Disables trapped I/O port accesses. noirqdebug [X86-32] Disables the code which attempts to detect and @@ -3691,11 +3743,6 @@ noreplace-smp [X86-32,SMP] Don't replace SMP instructions with UP alternatives - nordrand [X86] Disable kernel use of the RDRAND and - RDSEED instructions even if they are supported - by the processor. RDRAND and RDSEED are still - available to user space applications. - noresume [SWSUSP] Disables resume and restores original swap space. @@ -3721,20 +3768,6 @@ nox2apic [X86-64,APIC] Do not enable x2APIC mode. - cpu0_hotplug [X86] Turn on CPU0 hotplug feature when - CONFIG_BOOTPARAM_HOTPLUG_CPU0 is off. - Some features depend on CPU0. Known dependencies are: - 1. Resume from suspend/hibernate depends on CPU0. - Suspend/hibernate will fail if CPU0 is offline and you - need to online CPU0 before suspend/hibernate. - 2. PIC interrupts also depend on CPU0. CPU0 can't be - removed if a PIC interrupt is detected. - It's said poweroff/reboot may depend on CPU0 on some - machines although I haven't seen such issues so far - after CPU0 is offline on a few tested machines. - If the dependencies are under your control, you can - turn on cpu0_hotplug. - nps_mtm_hs_ctr= [KNL,ARC] This parameter sets the maximum duration, in cycles, each HW thread of the CTOP can run @@ -3787,6 +3820,16 @@ For example, to override I2C bus2: omap_mux=i2c2_scl.i2c2_scl=0x100,i2c2_sda.i2c2_sda=0x100 + onenand.bdry= [HW,MTD] Flex-OneNAND Boundary Configuration + + Format: [die0_boundary][,die0_lock][,die1_boundary][,die1_lock] + + boundary - index of last SLC block on Flex-OneNAND. + The remaining blocks are configured as MLC blocks. + lock - Configure if Flex-OneNAND boundary should be locked. + Once locked, the boundary cannot be changed. + 1 indicates lock status, 0 indicates unlock status. + oops=panic Always panic on oopses. Default is to just kill the process, but there is a small probability of deadlocking the machine. @@ -3857,14 +3900,6 @@ panic_on_warn panic() instead of WARN(). Useful to cause kdump on a WARN(). - crash_kexec_post_notifiers - Run kdump after running panic-notifiers and dumping - kmsg. This only for the users who doubt kdump always - succeeds in any situation. - Note that this also increases risks of kdump failure, - because some panic notifiers can make the crashed - kernel more unstable. - parkbd.port= [HW] Parallel port number the keyboard adapter is connected to, default is 0. Format: <parport#> @@ -4109,6 +4144,15 @@ please report a bug. nocrs [X86] Ignore PCI host bridge windows from ACPI. If you need to use this, please report a bug. + use_e820 [X86] Use E820 reservations to exclude parts of + PCI host bridge windows. This is a workaround + for BIOS defects in host bridge _CRS methods. + If you need to use this, please report a bug to + <linux-pci@vger.kernel.org>. + no_e820 [X86] Ignore E820 reservations for PCI host + bridge windows. This is the default on modern + hardware. If you need to use this, please report + a bug to <linux-pci@vger.kernel.org>. routeirq Do IRQ routing for all PCI devices. This is normally done in pci_enable_device(), so this option is a temporary workaround @@ -4518,6 +4562,9 @@ no-callback mode from boot but the mode may be toggled at runtime via cpusets. + Note that this argument takes precedence over + the CONFIG_RCU_NOCB_CPU_DEFAULT_ALL option. + rcu_nocb_poll [KNL] Rather than requiring that offloaded CPUs (specified by rcu_nocbs= above) explicitly @@ -4627,6 +4674,34 @@ When RCU_NOCB_CPU is set, also adjust the priority of NOCB callback kthreads. + rcutree.rcu_divisor= [KNL] + Set the shift-right count to use to compute + the callback-invocation batch limit bl from + the number of callbacks queued on this CPU. + The result will be bounded below by the value of + the rcutree.blimit kernel parameter. Every bl + callbacks, the softirq handler will exit in + order to allow the CPU to do other work. + + Please note that this callback-invocation batch + limit applies only to non-offloaded callback + invocation. Offloaded callbacks are instead + invoked in the context of an rcuoc kthread, which + scheduler will preempt as it does any other task. + + rcutree.nocb_nobypass_lim_per_jiffy= [KNL] + On callback-offloaded (rcu_nocbs) CPUs, + RCU reduces the lock contention that would + otherwise be caused by callback floods through + use of the ->nocb_bypass list. However, in the + common non-flooded case, RCU queues directly to + the main ->cblist in order to avoid the extra + overhead of the ->nocb_bypass list and its lock. + But if there are too many callbacks queued during + a single jiffy, RCU pre-queues the callbacks into + the ->nocb_bypass queue. The definition of "too + many" is supplied by this kernel boot parameter. + rcutree.rcu_nocb_gp_stride= [KNL] Set the number of NOCB callback kthreads in each group, which defaults to the square root @@ -5156,17 +5231,32 @@ Useful for devices that are detected asynchronously (e.g. USB and MMC devices). - hibernate= [HIBERNATION] - noresume Don't check if there's a hibernation image - present during boot. - nocompress Don't compress/decompress hibernation images. - no Disable hibernation and resume. - protect_image Turn on image protection during restoration - (that will set all pages holding image data - during restoration read-only). - retain_initrd [RAM] Keep initrd memory after extraction + retbleed= [X86] Control mitigation of RETBleed (Arbitrary + Speculative Code Execution with Return Instructions) + vulnerability. + + off - no mitigation + auto - automatically select a migitation + auto,nosmt - automatically select a mitigation, + disabling SMT if necessary for + the full mitigation (only on Zen1 + and older without STIBP). + ibpb - mitigate short speculation windows on + basic block boundaries too. Safe, highest + perf impact. + unret - force enable untrained return thunks, + only effective on AMD f15h-f17h + based systems. + unret,nosmt - like unret, will disable SMT when STIBP + is not available. + + Selecting 'auto' will choose a mitigation method at run + time according to the CPU. + + Not specifying this option is equivalent to retbleed=auto. + rfkill.default_state= 0 "airplane mode". All wifi, bluetooth, wimax, gps, fm, etc. communication is blocked by default. @@ -5480,7 +5570,7 @@ 1: Fast pin select (default) 2: ATC IRMode - smt [KNL,S390] Set the maximum number of threads (logical + smt= [KNL,S390] Set the maximum number of threads (logical CPUs) to use per physical CPU on systems capable of symmetric multithreading (SMT). Will be capped to the actual hardware limit. @@ -5538,6 +5628,7 @@ eibrs - enhanced IBRS eibrs,retpoline - enhanced IBRS + Retpolines eibrs,lfence - enhanced IBRS + LFENCE + ibrs - use IBRS to protect kernel Not specifying this option is equivalent to spectre_v2=auto. @@ -5741,6 +5832,24 @@ expediting. Set to zero to disable automatic expediting. + srcutree.srcu_max_nodelay [KNL] + Specifies the number of no-delay instances + per jiffy for which the SRCU grace period + worker thread will be rescheduled with zero + delay. Beyond this limit, worker thread will + be rescheduled with a sleep delay of one jiffy. + + srcutree.srcu_max_nodelay_phase [KNL] + Specifies the per-grace-period phase, number of + non-sleeping polls of readers. Beyond this limit, + grace period worker thread will be rescheduled + with a sleep delay of one jiffy, between each + rescan of the readers, for a grace period phase. + + srcutree.srcu_retry_check_delay [KNL] + Specifies number of microseconds of non-sleeping + delay between each non-sleeping poll of readers. + srcutree.small_contention_lim [KNL] Specifies the number of update-side contention events per jiffy will be tolerated before @@ -5867,8 +5976,9 @@ This parameter controls use of the Protected Execution Facility on pSeries. - swapaccount=[0|1] - [KNL] Enable accounting of swap in memory resource + swapaccount= [KNL] + Format: [0|1] + Enable accounting of swap in memory resource controller if no parameter or 1 is given or disable it if 0 is given (See Documentation/admin-guide/cgroup-v1/memory.rst) @@ -5914,7 +6024,8 @@ tdfx= [HW,DRM] - test_suspend= [SUSPEND][,N] + test_suspend= [SUSPEND] + Format: { "mem" | "standby" | "freeze" }[,N] Specify "mem" (for Suspend-to-RAM) or "standby" (for standby suspend) or "freeze" (for suspend type freeze) as the system sleep state during system startup with @@ -5998,32 +6109,7 @@ This will guarantee that all the other pcrs are saved. - trace_buf_size=nn[KMG] - [FTRACE] will set tracing buffer size on each cpu. - - trace_event=[event-list] - [FTRACE] Set and start specified trace events in order - to facilitate early boot debugging. The event-list is a - comma-separated list of trace events to enable. See - also Documentation/trace/events.rst - - trace_options=[option-list] - [FTRACE] Enable or disable tracer options at boot. - The option-list is a comma delimited list of options - that can be enabled or disabled just as if you were - to echo the option name into - - /sys/kernel/debug/tracing/trace_options - - For example, to enable stacktrace option (to dump the - stack trace of each event), add to the command line: - - trace_options=stacktrace - - See also Documentation/trace/ftrace.rst "trace options" - section. - - tp_printk[FTRACE] + tp_printk [FTRACE] Have the tracepoints sent to printk as well as the tracing ring buffer. This is useful for early boot up where the system hangs or reboots and does not give the @@ -6045,7 +6131,7 @@ frequency tracepoints such as irq or sched, can cause the system to live lock. - tp_printk_stop_on_boot[FTRACE] + tp_printk_stop_on_boot [FTRACE] When tp_printk (above) is set, it can cause a lot of noise on the console. It may be useful to only include the printing of events during boot up, as user space may @@ -6054,6 +6140,53 @@ This command line option will stop the printing of events to console at the late_initcall_sync() time frame. + trace_buf_size=nn[KMG] + [FTRACE] will set tracing buffer size on each cpu. + + trace_clock= [FTRACE] Set the clock used for tracing events + at boot up. + local - Use the per CPU time stamp counter + (converted into nanoseconds). Fast, but + depending on the architecture, may not be + in sync between CPUs. + global - Event time stamps are synchronize across + CPUs. May be slower than the local clock, + but better for some race conditions. + counter - Simple counting of events (1, 2, ..) + note, some counts may be skipped due to the + infrastructure grabbing the clock more than + once per event. + uptime - Use jiffies as the time stamp. + perf - Use the same clock that perf uses. + mono - Use ktime_get_mono_fast_ns() for time stamps. + mono_raw - Use ktime_get_raw_fast_ns() for time + stamps. + boot - Use ktime_get_boot_fast_ns() for time stamps. + Architectures may add more clocks. See + Documentation/trace/ftrace.rst for more details. + + trace_event=[event-list] + [FTRACE] Set and start specified trace events in order + to facilitate early boot debugging. The event-list is a + comma-separated list of trace events to enable. See + also Documentation/trace/events.rst + + trace_options=[option-list] + [FTRACE] Enable or disable tracer options at boot. + The option-list is a comma delimited list of options + that can be enabled or disabled just as if you were + to echo the option name into + + /sys/kernel/debug/tracing/trace_options + + For example, to enable stacktrace option (to dump the + stack trace of each event), add to the command line: + + trace_options=stacktrace + + See also Documentation/trace/ftrace.rst "trace options" + section. + traceoff_on_warning [FTRACE] enable this option to disable tracing when a warning is hit. This turns off "tracing_on". Tracing can @@ -6405,7 +6538,7 @@ HIGHMEM regardless of setting of CONFIG_HIGHPTE. - vdso= [X86,SH] + vdso= [X86,SH,SPARC] On X86_32, this is an alias for vdso32=. Otherwise: vdso=1: enable VDSO (the default) @@ -6431,11 +6564,12 @@ video= [FB] Frame buffer configuration See Documentation/fb/modedb.rst. - video.brightness_switch_enabled= [0,1] + video.brightness_switch_enabled= [ACPI] + Format: [0|1] If set to 1, on receiving an ACPI notify event generated by hotkey, video driver will adjust brightness level and then send out the event to user space through - the allocated input device; If set to 0, video driver + the allocated input device. If set to 0, video driver will only send out the event without touching backlight brightness level. default: 1 diff --git a/Documentation/admin-guide/media/vimc.dot b/Documentation/admin-guide/media/vimc.dot index 57863a13fa39..92a5bb631235 100644 --- a/Documentation/admin-guide/media/vimc.dot +++ b/Documentation/admin-guide/media/vimc.dot @@ -5,18 +5,22 @@ digraph board { n00000001 [label="{{} | Sensor A\n/dev/v4l-subdev0 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green] n00000001:port0 -> n00000005:port0 [style=bold] n00000001:port0 -> n0000000b [style=bold] + n00000001 -> n00000002 + n00000002 [label="{{} | Lens A\n/dev/v4l-subdev5 | {<port0>}}", shape=Mrecord, style=filled, fillcolor=green] n00000003 [label="{{} | Sensor B\n/dev/v4l-subdev1 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green] n00000003:port0 -> n00000008:port0 [style=bold] n00000003:port0 -> n0000000f [style=bold] + n00000003 -> n00000004 + n00000004 [label="{{} | Lens B\n/dev/v4l-subdev6 | {<port0>}}", shape=Mrecord, style=filled, fillcolor=green] n00000005 [label="{{<port0> 0} | Debayer A\n/dev/v4l-subdev2 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green] - n00000005:port1 -> n00000017:port0 + n00000005:port1 -> n00000015:port0 n00000008 [label="{{<port0> 0} | Debayer B\n/dev/v4l-subdev3 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green] - n00000008:port1 -> n00000017:port0 [style=dashed] + n00000008:port1 -> n00000015:port0 [style=dashed] n0000000b [label="Raw Capture 0\n/dev/video0", shape=box, style=filled, fillcolor=yellow] n0000000f [label="Raw Capture 1\n/dev/video1", shape=box, style=filled, fillcolor=yellow] - n00000013 [label="RGB/YUV Input\n/dev/video2", shape=box, style=filled, fillcolor=yellow] - n00000013 -> n00000017:port0 [style=dashed] - n00000017 [label="{{<port0> 0} | Scaler\n/dev/v4l-subdev4 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green] - n00000017:port1 -> n0000001a [style=bold] - n0000001a [label="RGB/YUV Capture\n/dev/video3", shape=box, style=filled, fillcolor=yellow] + n00000013 [label="{{} | RGB/YUV Input\n/dev/v4l-subdev4 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green] + n00000013:port0 -> n00000015:port0 [style=dashed] + n00000015 [label="{{<port0> 0} | Scaler\n/dev/v4l-subdev5 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green] + n00000015:port1 -> n00000018 [style=bold] + n00000018 [label="RGB/YUV Capture\n/dev/video2", shape=box, style=filled, fillcolor=yellow] } diff --git a/Documentation/admin-guide/media/vimc.rst b/Documentation/admin-guide/media/vimc.rst index 0b07f05dde25..3b4d2b36b4f3 100644 --- a/Documentation/admin-guide/media/vimc.rst +++ b/Documentation/admin-guide/media/vimc.rst @@ -53,6 +53,25 @@ vimc-sensor: * 1 Pad source +vimc-lens: + Ancillary lens for a sensor. Supports auto focus control. Linked to + a vimc-sensor using an ancillary link. The lens supports FOCUS_ABSOLUTE + control. + +.. code-block:: bash + + media-ctl -p + ... + - entity 28: Lens A (0 pad, 0 link) + type V4L2 subdev subtype Lens flags 0 + device node name /dev/v4l-subdev6 + - entity 29: Lens B (0 pad, 0 link) + type V4L2 subdev subtype Lens flags 0 + device node name /dev/v4l-subdev7 + v4l2-ctl -d /dev/v4l-subdev7 -C focus_absolute + focus_absolute: 0 + + vimc-debayer: Transforms images in bayer format into a non-bayer format. Exposes: diff --git a/Documentation/admin-guide/media/vivid.rst b/Documentation/admin-guide/media/vivid.rst index 6d7175f96f74..4f680dc9661c 100644 --- a/Documentation/admin-guide/media/vivid.rst +++ b/Documentation/admin-guide/media/vivid.rst @@ -714,6 +714,20 @@ The Test Pattern Controls are all specific to video capture. does the same for the EAV (End of Active Video) code. +- Insert Video Guard Band + + adds 4 columns of pixels with the HDMI Video Guard Band code at the + left hand side of the image. This only works with 3 or 4 byte RGB pixel + formats. The RGB pixel value 0xab/0x55/0xab turns out to be equivalent + to the HDMI Video Guard Band code that precedes each active video line + (see section 5.2.2.1 in the HDMI 1.3 Specification). To test if a video + receiver has correct HDMI Video Guard Band processing, enable this + control and then move the image to the left hand side of the screen. + That will result in video lines that start with multiple pixels that + have the same value as the Video Guard Band that precedes them. + Receivers that will just keep skipping Video Guard Band values will + now fail and either loose sync or these video lines will shift. + Capture Feature Selection Controls ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/Documentation/admin-guide/mm/damon/reclaim.rst b/Documentation/admin-guide/mm/damon/reclaim.rst index 0af51a9705b1..46306f1f34b1 100644 --- a/Documentation/admin-guide/mm/damon/reclaim.rst +++ b/Documentation/admin-guide/mm/damon/reclaim.rst @@ -66,6 +66,17 @@ Setting it as ``N`` disables DAMON_RECLAIM. Note that DAMON_RECLAIM could do no real monitoring and reclamation due to the watermarks-based activation condition. Refer to below descriptions for the watermarks parameter for this. +commit_inputs +------------- + +Make DAMON_RECLAIM reads the input parameters again, except ``enabled``. + +Input parameters that updated while DAMON_RECLAIM is running are not applied +by default. Once this parameter is set as ``Y``, DAMON_RECLAIM reads values +of parametrs except ``enabled`` again. Once the re-reading is done, this +parameter is set as ``N``. If invalid parameters are found while the +re-reading, DAMON_RECLAIM will be disabled. + min_age ------- diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index 592ea9a50881..1bb7b72414b2 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -68,7 +68,7 @@ comma (","). :: │ kdamonds/nr_kdamonds │ │ 0/state,pid │ │ │ contexts/nr_contexts - │ │ │ │ 0/operations + │ │ │ │ 0/avail_operations,operations │ │ │ │ │ monitoring_attrs/ │ │ │ │ │ │ intervals/sample_us,aggr_us,update_us │ │ │ │ │ │ nr_regions/min,max @@ -121,10 +121,11 @@ In each kdamond directory, two files (``state`` and ``pid``) and one directory Reading ``state`` returns ``on`` if the kdamond is currently running, or ``off`` if it is not running. Writing ``on`` or ``off`` makes the kdamond be -in the state. Writing ``update_schemes_stats`` to ``state`` file updates the -contents of stats files for each DAMON-based operation scheme of the kdamond. -For details of the stats, please refer to :ref:`stats section -<sysfs_schemes_stats>`. +in the state. Writing ``commit`` to the ``state`` file makes kdamond reads the +user inputs in the sysfs files except ``state`` file again. Writing +``update_schemes_stats`` to ``state`` file updates the contents of stats files +for each DAMON-based operation scheme of the kdamond. For details of the +stats, please refer to :ref:`stats section <sysfs_schemes_stats>`. If the state is ``on``, reading ``pid`` shows the pid of the kdamond thread. @@ -143,17 +144,28 @@ be written to the file. contexts/<N>/ ------------- -In each context directory, one file (``operations``) and three directories -(``monitoring_attrs``, ``targets``, and ``schemes``) exist. +In each context directory, two files (``avail_operations`` and ``operations``) +and three directories (``monitoring_attrs``, ``targets``, and ``schemes``) +exist. DAMON supports multiple types of monitoring operations, including those for -virtual address space and the physical address space. You can set and get what -type of monitoring operations DAMON will use for the context by writing one of -below keywords to, and reading from the file. +virtual address space and the physical address space. You can get the list of +available monitoring operations set on the currently running kernel by reading +``avail_operations`` file. Based on the kernel configuration, the file will +list some or all of below keywords. - vaddr: Monitor virtual address spaces of specific processes + - fvaddr: Monitor fixed virtual address ranges - paddr: Monitor the physical address space of the system +Please refer to :ref:`regions sysfs directory <sysfs_regions>` for detailed +differences between the operations sets in terms of the monitoring target +regions. + +You can set and get what type of monitoring operations DAMON will use for the +context by writing one of the keywords listed in ``avail_operations`` file and +reading from the ``operations`` file. + contexts/<N>/monitoring_attrs/ ------------------------------ @@ -192,6 +204,8 @@ If you wrote ``vaddr`` to the ``contexts/<N>/operations``, each target should be a process. You can specify the process to DAMON by writing the pid of the process to the ``pid_target`` file. +.. _sysfs_regions: + targets/<N>/regions ------------------- @@ -202,9 +216,10 @@ can be covered. However, users could want to set the initial monitoring region to specific address ranges. In contrast, DAMON do not automatically sets and updates the monitoring target -regions when ``paddr`` monitoring operations set is being used (``paddr`` is -written to the ``contexts/<N>/operations``). Therefore, users should set the -monitoring target regions by themselves in the case. +regions when ``fvaddr`` or ``paddr`` monitoring operations sets are being used +(``fvaddr`` or ``paddr`` have written to the ``contexts/<N>/operations``). +Therefore, users should set the monitoring target regions by themselves in the +cases. For such cases, users can explicitly set the initial monitoring target regions as they want, by writing proper values to the files under this directory. diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst index 0166f9de3428..a90330d0a837 100644 --- a/Documentation/admin-guide/mm/hugetlbpage.rst +++ b/Documentation/admin-guide/mm/hugetlbpage.rst @@ -164,7 +164,7 @@ default_hugepagesz will all result in 256 2M huge pages being allocated. Valid default huge page size is architecture dependent. hugetlb_free_vmemmap - When CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is set, this enables freeing + When CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP is set, this enables optimizing unused vmemmap pages associated with each HugeTLB page. When multiple huge page sizes are supported, ``/proc/sys/vm/nr_hugepages`` diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index 97d816791aca..b244f0202a03 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -184,6 +184,24 @@ The maximum possible ``pages_sharing/pages_shared`` ratio is limited by the ``max_page_sharing`` tunable. To increase the ratio ``max_page_sharing`` must be increased accordingly. +Monitoring KSM events +===================== + +There are some counters in /proc/vmstat that may be used to monitor KSM events. +KSM might help save memory, it's a tradeoff by may suffering delay on KSM COW +or on swapping in copy. Those events could help users evaluate whether or how +to use KSM. For example, if cow_ksm increases too fast, user may decrease the +range of madvise(, , MADV_MERGEABLE). + +cow_ksm + is incremented every time a KSM page triggers copy on write (COW) + when users try to write to a KSM page, we have to make a copy. + +ksm_swpin_copy + is incremented every time a KSM page is copied when swapping in + note that KSM page might be copied when swapping in because do_swap_page() + cannot do all the locking needed to reconstitute a cross-anon_vma KSM page. + -- Izik Eidus, Hugh Dickins, 17 Nov 2009 diff --git a/Documentation/admin-guide/nfs/nfs-client.rst b/Documentation/admin-guide/nfs/nfs-client.rst index 6adb6457bc69..36760685dd34 100644 --- a/Documentation/admin-guide/nfs/nfs-client.rst +++ b/Documentation/admin-guide/nfs/nfs-client.rst @@ -36,10 +36,9 @@ administrative requirements that require particular behavior that does not work well as part of an nfs_client_id4 string. The nfs.nfs4_unique_id boot parameter specifies a unique string that can be -used instead of a system's node name when an NFS client identifies itself to -a server. Thus, if the system's node name is not unique, or it changes, its -nfs.nfs4_unique_id stays the same, preventing collision with other clients -or loss of state during NFS reboot recovery or transparent state migration. +used together with a system's node name when an NFS client identifies itself to +a server. Thus, if the system's node name is not unique, its +nfs.nfs4_unique_id can help prevent collisions with other clients. The nfs.nfs4_unique_id string is typically a UUID, though it can contain anything that is believed to be unique across all NFS clients. An @@ -53,8 +52,12 @@ outstanding NFSv4 state has expired, to prevent loss of NFSv4 state. This string can be stored in an NFS client's grub.conf, or it can be provided via a net boot facility such as PXE. It may also be specified as an nfs.ko -module parameter. Specifying a uniquifier string is not support for NFS -clients running in containers. +module parameter. + +This uniquifier string will be the same for all NFS clients running in +containers unless it is overridden by a value written to +/sys/fs/nfs/net/nfs_client/identifier which will be local to the network +namespace of the process which writes. The DNS resolver diff --git a/Documentation/admin-guide/perf/hns3-pmu.rst b/Documentation/admin-guide/perf/hns3-pmu.rst new file mode 100644 index 000000000000..578407e487d6 --- /dev/null +++ b/Documentation/admin-guide/perf/hns3-pmu.rst @@ -0,0 +1,136 @@ +====================================== +HNS3 Performance Monitoring Unit (PMU) +====================================== + +HNS3(HiSilicon network system 3) Performance Monitoring Unit (PMU) is an +End Point device to collect performance statistics of HiSilicon SoC NIC. +On Hip09, each SICL(Super I/O cluster) has one PMU device. + +HNS3 PMU supports collection of performance statistics such as bandwidth, +latency, packet rate and interrupt rate. + +Each HNS3 PMU supports 8 hardware events. + +HNS3 PMU driver +=============== + +The HNS3 PMU driver registers a perf PMU with the name of its sicl id.:: + + /sys/devices/hns3_pmu_sicl_<sicl_id> + +PMU driver provides description of available events, filter modes, format, +identifier and cpumask in sysfs. + +The "events" directory describes the event code of all supported events +shown in perf list. + +The "filtermode" directory describes the supported filter modes of each +event. + +The "format" directory describes all formats of the config (events) and +config1 (filter options) fields of the perf_event_attr structure. + +The "identifier" file shows version of PMU hardware device. + +The "bdf_min" and "bdf_max" files show the supported bdf range of each +pmu device. + +The "hw_clk_freq" file shows the hardware clock frequency of each pmu +device. + +Example usage of checking event code and subevent code:: + + $# cat /sys/devices/hns3_pmu_sicl_0/events/dly_tx_normal_to_mac_time + config=0x00204 + $# cat /sys/devices/hns3_pmu_sicl_0/events/dly_tx_normal_to_mac_packet_num + config=0x10204 + +Each performance statistic has a pair of events to get two values to +calculate real performance data in userspace. + +The bits 0~15 of config (here 0x0204) are the true hardware event code. If +two events have same value of bits 0~15 of config, that means they are +event pair. And the bit 16 of config indicates getting counter 0 or +counter 1 of hardware event. + +After getting two values of event pair in usersapce, the formula of +computation to calculate real performance data is::: + + counter 0 / counter 1 + +Example usage of checking supported filter mode:: + + $# cat /sys/devices/hns3_pmu_sicl_0/filtermode/bw_ssu_rpu_byte_num + filter mode supported: global/port/port-tc/func/func-queue/ + +Example usage of perf:: + + $# perf list + hns3_pmu_sicl_0/bw_ssu_rpu_byte_num/ [kernel PMU event] + hns3_pmu_sicl_0/bw_ssu_rpu_time/ [kernel PMU event] + ------------------------------------------ + + $# perf stat -g -e hns3_pmu_sicl_0/bw_ssu_rpu_byte_num,global=1/ -e hns3_pmu_sicl_0/bw_ssu_rpu_time,global=1/ -I 1000 + or + $# perf stat -g -e hns3_pmu_sicl_0/config=0x00002,global=1/ -e hns3_pmu_sicl_0/config=0x10002,global=1/ -I 1000 + + +Filter modes +-------------- + +1. global mode +PMU collect performance statistics for all HNS3 PCIe functions of IO DIE. +Set the "global" filter option to 1 will enable this mode. +Example usage of perf:: + + $# perf stat -a -e hns3_pmu_sicl_0/config=0x1020F,global=1/ -I 1000 + +2. port mode +PMU collect performance statistic of one whole physical port. The port id +is same as mac id. The "tc" filter option must be set to 0xF in this mode, +here tc stands for traffic class. + +Example usage of perf:: + + $# perf stat -a -e hns3_pmu_sicl_0/config=0x1020F,port=0,tc=0xF/ -I 1000 + +3. port-tc mode +PMU collect performance statistic of one tc of physical port. The port id +is same as mac id. The "tc" filter option must be set to 0 ~ 7 in this +mode. +Example usage of perf:: + + $# perf stat -a -e hns3_pmu_sicl_0/config=0x1020F,port=0,tc=0/ -I 1000 + +4. func mode +PMU collect performance statistic of one PF/VF. The function id is BDF of +PF/VF, its conversion formula:: + + func = (bus << 8) + (device << 3) + (function) + +for example: + BDF func + 35:00.0 0x3500 + 35:00.1 0x3501 + 35:01.0 0x3508 + +In this mode, the "queue" filter option must be set to 0xFFFF. +Example usage of perf:: + + $# perf stat -a -e hns3_pmu_sicl_0/config=0x1020F,bdf=0x3500,queue=0xFFFF/ -I 1000 + +5. func-queue mode +PMU collect performance statistic of one queue of PF/VF. The function id +is BDF of PF/VF, the "queue" filter option must be set to the exact queue +id of function. +Example usage of perf:: + + $# perf stat -a -e hns3_pmu_sicl_0/config=0x1020F,bdf=0x3500,queue=0/ -I 1000 + +6. func-intr mode +PMU collect performance statistic of one interrupt of PF/VF. The function +id is BDF of PF/VF, the "intr" filter option must be set to the exact +interrupt id of function. +Example usage of perf:: + + $# perf stat -a -e hns3_pmu_sicl_0/config=0x00301,bdf=0x3500,intr=0/ -I 1000 diff --git a/Documentation/admin-guide/perf/index.rst b/Documentation/admin-guide/perf/index.rst index 69b23f087c05..9c9ece88ce53 100644 --- a/Documentation/admin-guide/perf/index.rst +++ b/Documentation/admin-guide/perf/index.rst @@ -9,6 +9,7 @@ Performance monitor support hisi-pmu hisi-pcie-pmu + hns3-pmu imx-ddr qcom_l2_pmu qcom_l3_pmu diff --git a/Documentation/admin-guide/pm/cpuidle.rst b/Documentation/admin-guide/pm/cpuidle.rst index aec2cd2aaea7..19754beb5a4e 100644 --- a/Documentation/admin-guide/pm/cpuidle.rst +++ b/Documentation/admin-guide/pm/cpuidle.rst @@ -612,8 +612,8 @@ the ``menu`` governor to be used on the systems that use the ``ladder`` governor by default this way, for example. The other kernel command line parameters controlling CPU idle time management -described below are only relevant for the *x86* architecture and some of -them affect Intel processors only. +described below are only relevant for the *x86* architecture and references +to ``intel_idle`` affect Intel processors only. The *x86* architecture support code recognizes three kernel command line options related to CPU idle time management: ``idle=poll``, ``idle=halt``, @@ -635,10 +635,13 @@ idle, so it very well may hurt single-thread computations performance as well as energy-efficiency. Thus using it for performance reasons may not be a good idea at all.] -The ``idle=nomwait`` option disables the ``intel_idle`` driver and causes -``acpi_idle`` to be used (as long as all of the information needed by it is -there in the system's ACPI tables), but it is not allowed to use the -``MWAIT`` instruction of the CPUs to ask the hardware to enter idle states. +The ``idle=nomwait`` option prevents the use of ``MWAIT`` instruction of +the CPU to enter idle states. When this option is used, the ``acpi_idle`` +driver will use the ``HLT`` instruction instead of ``MWAIT``. On systems +running Intel processors, this option disables the ``intel_idle`` driver +and forces the use of the ``acpi_idle`` driver instead. Note that in either +case, ``acpi_idle`` driver will function only if all the information needed +by it is in the system's ACPI tables. In addition to the architecture-level kernel command line options affecting CPU idle time management, there are parameters affecting individual ``CPUIdle`` diff --git a/Documentation/admin-guide/pm/intel-speed-select.rst b/Documentation/admin-guide/pm/intel-speed-select.rst index 0a1fbdb54bfe..a2bfb971654f 100644 --- a/Documentation/admin-guide/pm/intel-speed-select.rst +++ b/Documentation/admin-guide/pm/intel-speed-select.rst @@ -262,6 +262,28 @@ Which shows that the base frequency now increased from 2600 MHz at performance level 0 to 2800 MHz at performance level 4. As a result, any workload, which can use fewer CPUs, can see a boost of 200 MHz compared to performance level 0. +Changing performance level via BMC Interface +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +It is possible to change SST-PP level using out of band (OOB) agent (Via some +remote management console, through BMC "Baseboard Management Controller" +interface). This mode is supported from the Sapphire Rapids processor +generation. The kernel and tool change to support this mode is added to Linux +kernel version 5.18. To enable this feature, kernel config +"CONFIG_INTEL_HFI_THERMAL" is required. The minimum version of the tool +is "v1.12" to support this feature, which is part of Linux kernel version 5.18. + +To support such configuration, this tool can be used as a daemon. Add +a command line option --oob:: + + # intel-speed-select --oob + Intel(R) Speed Select Technology + Executing on CPU model:143[0x8f] + OOB mode is enabled and will run as daemon + +In this mode the tool will online/offline CPUs based on the new performance +level. + Check presence of other Intel(R) SST features --------------------------------------------- diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index e9c18dabc552..8ab042beeb76 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -38,8 +38,8 @@ acct If BSD-style process accounting is enabled these values control its behaviour. If free space on filesystem where the log lives -goes below ``lowwater``% accounting suspends. If free space gets -above ``highwater``% accounting resumes. ``frequency`` determines +goes below ``lowwater``\ % accounting suspends. If free space gets +above ``highwater``\ % accounting resumes. ``frequency`` determines how often do we check the amount of free space (value is in seconds). Default: @@ -783,6 +783,13 @@ is useful to define the root cause of RCU stalls using a vmcore. 1 panic() after printing RCU stall messages. = ============================================================ +max_rcu_stall_to_panic +====================== + +When ``panic_on_rcu_stall`` is set to 1, this value determines the +number of times that RCU can stall before panic() is called. + +When ``panic_on_rcu_stall`` is set to 0, this value is has no effect. perf_cpu_time_max_percent ========================= diff --git a/Documentation/admin-guide/sysctl/net.rst b/Documentation/admin-guide/sysctl/net.rst index f86b5e1623c6..805f2281e000 100644 --- a/Documentation/admin-guide/sysctl/net.rst +++ b/Documentation/admin-guide/sysctl/net.rst @@ -322,6 +322,14 @@ a leaked reference faster. A larger value may be useful to prevent false warnings on slow/loaded systems. Default value is 10, minimum 1, maximum 3600. +skb_defer_max +------------- + +Max size (in skbs) of the per-cpu list of skbs being freed +by the cpu which allocated them. Used by TCP stack so far. + +Default: 64 + optmem_max ---------- @@ -374,6 +382,27 @@ option is set to SOCK_TXREHASH_DEFAULT (i. e. not overridden by setsockopt). If set to 1 (default), hash rethink is performed on listening socket. If set to 0, hash rethink is not performed. +gro_normal_batch +---------------- + +Maximum number of the segments to batch up on output of GRO. When a packet +exits GRO, either as a coalesced superframe or as an original packet which +GRO has decided not to coalesce, it is placed on a per-NAPI list. This +list is then passed to the stack when the number of segments reaches the +gro_normal_batch limit. + +high_order_alloc_disable +------------------------ + +By default the allocator for page frags tries to use high order pages (order-3 +on x86). While the default behavior gives good results in most cases, some users +might have hit a contention in page allocations/freeing. This was especially +true on older kernels (< 5.14) when high-order pages were not stored on per-cpu +lists. This allows to opt-in for order-0 allocation instead but is now mostly of +historical importance. + +Default: 0 + 2. /proc/sys/net/unix - Parameters for Unix domain sockets ---------------------------------------------------------- diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst index f4804ce37c58..5c9aa171a0d3 100644 --- a/Documentation/admin-guide/sysctl/vm.rst +++ b/Documentation/admin-guide/sysctl/vm.rst @@ -62,6 +62,7 @@ Currently, these files are in /proc/sys/vm: - overcommit_memory - overcommit_ratio - page-cluster +- page_lock_unfairness - panic_on_oom - percpu_pagelist_high_fraction - stat_interval @@ -561,6 +562,45 @@ Change the minimum size of the hugepage pool. See Documentation/admin-guide/mm/hugetlbpage.rst +hugetlb_optimize_vmemmap +======================== + +This knob is not available when memory_hotplug.memmap_on_memory (kernel parameter) +is configured or the size of 'struct page' (a structure defined in +include/linux/mm_types.h) is not power of two (an unusual system config could +result in this). + +Enable (set to 1) or disable (set to 0) the feature of optimizing vmemmap pages +associated with each HugeTLB page. + +Once enabled, the vmemmap pages of subsequent allocation of HugeTLB pages from +buddy allocator will be optimized (7 pages per 2MB HugeTLB page and 4095 pages +per 1GB HugeTLB page), whereas already allocated HugeTLB pages will not be +optimized. When those optimized HugeTLB pages are freed from the HugeTLB pool +to the buddy allocator, the vmemmap pages representing that range needs to be +remapped again and the vmemmap pages discarded earlier need to be rellocated +again. If your use case is that HugeTLB pages are allocated 'on the fly' (e.g. +never explicitly allocating HugeTLB pages with 'nr_hugepages' but only set +'nr_overcommit_hugepages', those overcommitted HugeTLB pages are allocated 'on +the fly') instead of being pulled from the HugeTLB pool, you should weigh the +benefits of memory savings against the more overhead (~2x slower than before) +of allocation or freeing HugeTLB pages between the HugeTLB pool and the buddy +allocator. Another behavior to note is that if the system is under heavy memory +pressure, it could prevent the user from freeing HugeTLB pages from the HugeTLB +pool to the buddy allocator since the allocation of vmemmap pages could be +failed, you have to retry later if your system encounter this situation. + +Once disabled, the vmemmap pages of subsequent allocation of HugeTLB pages from +buddy allocator will not be optimized meaning the extra overhead at allocation +time from buddy allocator disappears, whereas already optimized HugeTLB pages +will not be affected. If you want to make sure there are no optimized HugeTLB +pages, you can set "nr_hugepages" to 0 first and then disable this. Note that +writing 0 to nr_hugepages will make any "in use" HugeTLB pages become surplus +pages. So, those surplus pages are still optimized until they are no longer +in use. You would need to wait for those surplus pages to be released before +there are no optimized pages in the system. + + nr_hugepages_mempolicy ====================== @@ -754,6 +794,14 @@ extra faults and I/O delays for following faults if they would have been part of that consecutive pages readahead would have brought in. +page_lock_unfairness +==================== + +This value determines the number of times that the page lock can be +stolen from under a waiter. After the lock is stolen the number of times +specified in this file (default is 5), the "fair lock handoff" semantics +will apply, and the waiter will only be awakened if the lock can be taken. + panic_on_oom ============ diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst index ceeed7b0798d..7d80e8c307d1 100644 --- a/Documentation/admin-guide/tainted-kernels.rst +++ b/Documentation/admin-guide/tainted-kernels.rst @@ -100,6 +100,7 @@ Bit Log Number Reason that got the kernel tainted 15 _/K 32768 kernel has been live patched 16 _/X 65536 auxiliary taint, defined for and used by distros 17 _/T 131072 kernel was built with the struct randomization plugin + 18 _/N 262144 an in-kernel test has been run === === ====== ======================================================== Note: The character ``_`` is representing a blank in this table to make reading |