summaryrefslogtreecommitdiff
path: root/Documentation/admin-guide
AgeCommit message (Collapse)Author
2025-03-25Merge tag 'media/v6.15-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media Pull media updates from Mauro Carvalho Chehab: - platform: synopsys: hdmirx: Fix 64-bit division for 32-bit targets - vim2m: print device name after registering device - Synopsys DesignWare HDMI RX Driver and various fixes - cec/printk fixes and the removal of the vidioc_g/s_ctrl and vidioc_queryctrl callbacks - AVerMedia H789-C PCIe support and rc-core structs padding - Several camera sensor patches - uvcvideo improvements - visl: Fix ERANGE error when setting enum controls - codec fixes - V4L2 camera sensor patches mostly - chips-media: wave5: Fixes - Add SDM670 camera subsystem - Qualcomm iris video decoder driver - dt-bindings: update clocks for sc7280-camss - various fixes and enhancements * tag 'media/v6.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (264 commits) media: pci: mgb4: include linux/errno.h media: synopsys: hdmirx: Fix signedness bug in hdmirx_parse_dt() media: platform: synopsys: hdmirx: Fix 64-bit division for 32-bit targets media: vim2m: print device name after registering device media: vivid: Introduce VIDEO_VIVID_OSD media: vivid: Move all fb_info references into vivid-osd media: platform: synopsys: hdmirx: Optimize struct snps_hdmirx_dev media: platform: synopsys: hdmirx: Remove unused HDMI audio CODEC relics media: platform: synopsys: hdmirx: Remove duplicated header inclusion media: qcom: Clean up Kconfig dependencies media: dvb-frontends: tda10048: Make the range of z explicit. media: platform: stm32: Add check for clk_enable() media: xilinx-tpg: fix double put in xtpg_parse_of() media: siano: Fix error handling in smsdvb_module_init() media: c8sectpfe: Call of_node_put(i2c_bus) only once in c8sectpfe_probe() media: i2c: tda1997x: Call of_node_put(ep) only once in tda1997x_parse_dt() dt-bindings: media: mediatek,vcodec: Revise description dt-bindings: media: mediatek,jpeg: Relax IOMMU max item count media: v4l2-dv-timings: prevent possible overflow in v4l2_detect_gtf() media: rockchip: rga: fix rga offset lookup ...
2025-03-25Merge tag 'pm-6.15-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management updates from Rafael Wysocki: "These are dominated by cpufreq updates which in turn are dominated by updates related to boost support in the core and drivers and amd-pstate driver optimizations. Apart from the above, there are some cpuidle updates including a rework of the most recent idle intervals handling in the venerable menu governor that leads to significant improvements in some performance benchmarks, as the governor is now more likely to predict a shorter idle duration in some cases, and there are updates of the core device power management code, mostly related to system suspend and resume, that should help to avoid potential issues arising when the drivers of devices depending on one another want to use different optimizations. There is also a usual collection of assorted fixes and cleanups, including removal of some unused code. Specifics: - Manage sysfs attributes and boost frequencies efficiently from cpufreq core to reduce boilerplate code in drivers (Viresh Kumar) - Minor cleanups to cpufreq drivers (Aaron Kling, Benjamin Schneider, Dhananjay Ugwekar, Imran Shaik, zuoqian) - Migrate some cpufreq drivers to using for_each_present_cpu() (Jacky Bai) - cpufreq-qcom-hw DT binding fixes (Krzysztof Kozlowski) - Use str_enable_disable() helper in cpufreq_online() (Lifeng Zheng) - Optimize the amd-pstate driver to avoid cases where call paths end up calling the same writes multiple times and needlessly caching variables through code reorganization, locking overhaul and tracing adjustments (Mario Limonciello, Dhananjay Ugwekar) - Make it possible to avoid enabling capacity-aware scheduling (CAS) in the intel_pstate driver and relocate a check for out-of-band (OOB) platform handling in it to make it detect OOB before checking HWP availability (Rafael Wysocki) - Fix dbs_update() to avoid inadvertent conversions of negative integer values to unsigned int which causes CPU frequency selection to be inaccurate in some cases when the "conservative" cpufreq governor is in use (Jie Zhan) - Update the handling of the most recent idle intervals in the menu cpuidle governor to prevent useful information from being discarded by it in some cases and improve the prediction accuracy (Rafael Wysocki) - Make it possible to tell the intel_idle driver to ignore its built-in table of idle states for the given processor, clean up the handling of auto-demotion disabling on Baytrail and Cherrytrail chips in it, and update its MAINTAINERS entry (David Arcari, Artem Bityutskiy, Rafael Wysocki) - Make some cpuidle drivers use for_each_present_cpu() instead of for_each_possible_cpu() during initialization to avoid issues occurring when nosmp or maxcpus=0 are used (Jacky Bai) - Clean up the Energy Model handling code somewhat (Rafael Wysocki) - Use kfree_rcu() to simplify the handling of runtime Energy Model updates (Li RongQing) - Add an entry for the Energy Model framework to MAINTAINERS as properly maintained (Lukasz Luba) - Address RCU-related sparse warnings in the Energy Model code (Rafael Wysocki) - Remove ENERGY_MODEL dependency on SMP and allow it to be selected when DEVFREQ is set without CPUFREQ so it can be used on a wider range of systems (Jeson Gao) - Unify error handling during runtime suspend and runtime resume in the core to help drivers to implement more consistent runtime PM error handling (Rafael Wysocki) - Drop a redundant check from pm_runtime_force_resume() and rearrange documentation related to __pm_runtime_disable() (Rafael Wysocki) - Rework the handling of the "smart suspend" driver flag in the PM core to avoid issues hat may occur when drivers using it depend on some other drivers and clean up the related PM core code (Rafael Wysocki, Colin Ian King) - Fix the handling of devices with the power.direct_complete flag set if device_suspend() returns an error for at least one device to avoid situations in which some of them may not be resumed (Rafael Wysocki) - Use mutex_trylock() in hibernate_compressor_param_set() to avoid a possible deadlock that may occur if the "compressor" hibernation module parameter is accessed during the registration of a new ieee80211 device (Lizhi Xu) - Suppress sleeping parent warning in device_pm_add() in the case when new children are added under a device with the power.direct_complete set after it has been processed by device_resume() (Xu Yang) - Remove needless return in three void functions related to system wakeup (Zijun Hu) - Replace deprecated kmap_atomic() with kmap_local_page() in the hibernation core code (David Reaver) - Remove unused helper functions related to system sleep (David Alan Gilbert) - Clean up s2idle_enter() so it does not lock and unlock CPU offline in vain and update comments in it (Ulf Hansson) - Clean up broken white space in dpm_wait_for_children() (Geert Uytterhoeven) - Update the cpupower utility to fix lib version-ing in it and memory leaks in error legs, remove hard-coded values, and implement CPU physical core querying (Thomas Renninger, John B. Wyatt IV, Shuah Khan, Yiwei Lin, Zhongqiu Han)" * tag 'pm-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (139 commits) PM: sleep: Fix bit masking operation dt-bindings: cpufreq: cpufreq-qcom-hw: Narrow properties on SDX75, SA8775p and SM8650 dt-bindings: cpufreq: cpufreq-qcom-hw: Drop redundant minItems:1 dt-bindings: cpufreq: cpufreq-qcom-hw: Add missing constraint for interrupt-names dt-bindings: cpufreq: cpufreq-qcom-hw: Add QCS8300 compatible cpufreq: Init cpufreq only for present CPUs PM: sleep: Fix handling devices with direct_complete set on errors cpuidle: Init cpuidle only for present CPUs PM: clk: Remove unused pm_clk_remove() PM: sleep: core: Fix indentation in dpm_wait_for_children() PM: s2idle: Extend comment in s2idle_enter() PM: s2idle: Drop redundant locks when entering s2idle PM: sleep: Remove unused pm_generic_ wrappers cpufreq: tegra186: Share policy per cluster cpupower: Make lib versioning scheme more obvious and fix version link PM: EM: Rework the depends on for CONFIG_ENERGY_MODEL PM: EM: Address RCU-related sparse warnings cpupower: Implement CPU physical core querying pm: cpupower: remove hard-coded topology depth values pm: cpupower: Fix cmd_monitor() error legs to free cpu_topology ...
2025-03-25Merge tag 'acpi-6.15-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull ACPI updates from Rafael Wysocki: "From the functional perspective, the most significant changes here are the ACPI fan driver update allowing it to handle fans with fine-grained state checking supported, but without fine-grained control, and the ACPI button driver update making it subscribe to system event notifications (in addition to device notifications) which on some systems is requisite for waking up the system from sleep. The rest is fixes and cleanups including removal of some dead code. Specifics: - Use the str_on_off() helper function instead of hard-coded strings in the ACPI power resources handling code (Thorsten Blum) - Add fan speed reporting for ACPI fans that have _FST, but otherwise do not support the entire ACPI 4 fan interface (Joshua Grisham) - Fix a stale comment regarding trip points in acpi_thermal_add() that diverged from the commented code after removing _CRT evaluation from acpi_thermal_get_trip_points() (xueqin Luo) - Make ACPI button driver also subscribe to system events (Mario Limonciello) - Use the str_yes_no() helper function instead of hard-coded strings in the ACPI backlight (video) driver (Thorsten Blum) - Add a missing header file include to the x86 arch CPPC code (Mario Limonciello) - Rework the sysfs attributes implementation in the ACPI platform-profile driver and improve the unregistration code in it (Nathan Chancellor, Kurt Borja) - Prevent the ACPI HED driver from being built as a module and change its initcall level to subsys_initcall to avoid initialization ordering issues related to it (Xiaofei Tan) - Update a maintainer email address in the ACPI PMIC entry in MAINTAINERS (Mika Westerberg) - Address a GCC 15's -Wunterminated-string-initialization warning in the core PNP subsystem code and remove some dead code from it (Kees Cook, David Alan Gilbert)" * tag 'acpi-6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PNP: Expand length of fixup id string PNP: Remove prehistoric deadcode ACPI: button: Install notifier for system events as well ACPI: fan: Add fan speed reporting for fans with only _FST ACPI: HED: Always initialize before evged x86/ACPI: CPPC: Add missing include ACPI: video: Use str_yes_no() helper in acpi_video_bus_add() ACPI: platform_profile: Improve platform_profile_unregister() ACPI: platform-profile: Fix CFI violation when accessing sysfs files ACPI: power: Use str_on_off() helper function ACPI: thermal: Fix stale comment regarding trip points MAINTAINERS: Use my kernel.org address for ACPI PMIC work
2025-03-25Merge tag 'x86_bugs_for_v6.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 speculation mitigation updates from Borislav Petkov: - Some preparatory work to convert the mitigations machinery to mitigating attack vectors instead of single vulnerabilities - Untangle and remove a now unneeded X86_FEATURE_USE_IBPB flag - Add support for a Zen5-specific SRSO mitigation - Cleanups and minor improvements * tag 'x86_bugs_for_v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/bugs: Make spectre user default depend on MITIGATION_SPECTRE_V2 x86/bugs: Use the cpu_smt_possible() helper instead of open-coded code x86/bugs: Add AUTO mitigations for mds/taa/mmio/rfds x86/bugs: Relocate mds/taa/mmio/rfds defines x86/bugs: Add X86_BUG_SPECTRE_V2_USER x86/bugs: Remove X86_FEATURE_USE_IBPB KVM: nVMX: Always use IBPB to properly virtualize IBRS x86/bugs: Use a static branch to guard IBPB on vCPU switch x86/bugs: Remove the X86_FEATURE_USE_IBPB check in ib_prctl_set() x86/mm: Remove X86_FEATURE_USE_IBPB checks in cond_mitigation() x86/bugs: Move the X86_FEATURE_USE_IBPB check into callers x86/bugs: KVM: Add support for SRSO_MSR_FIX
2025-03-25Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Catalin Marinas: "Nothing major this time around. Apart from the usual perf/PMU updates, some page table cleanups, the notable features are average CPU frequency based on the AMUv1 counters, CONFIG_HOTPLUG_SMT and MOPS instructions (memcpy/memset) in the uaccess routines. Perf and PMUs: - Support for the 'Rainier' CPU PMU from Arm - Preparatory driver changes and cleanups that pave the way for BRBE support - Support for partial virtualisation of the Apple-M1 PMU - Support for the second event filter in Arm CSPMU designs - Minor fixes and cleanups (CMN and DWC PMUs) - Enable EL2 requirements for FEAT_PMUv3p9 Power, CPU topology: - Support for AMUv1-based average CPU frequency - Run-time SMT control wired up for arm64 (CONFIG_HOTPLUG_SMT). It adds a generic topology_is_primary_thread() function overridden by x86 and powerpc New(ish) features: - MOPS (memcpy/memset) support for the uaccess routines Security/confidential compute: - Fix the DMA address for devices used in Realms with Arm CCA. The CCA architecture uses the address bit to differentiate between shared and private addresses - Spectre-BHB: assume CPUs Linux doesn't know about vulnerable by default Memory management clean-ups: - Drop the P*D_TABLE_BIT definition in preparation for 128-bit PTEs - Some minor page table accessor clean-ups - PIE/POE (permission indirection/overlay) helpers clean-up Kselftests: - MTE: skip hugetlb tests if MTE is not supported on such mappings and user correct naming for sync/async tag checking modes Miscellaneous: - Add a PKEY_UNRESTRICTED definition as 0 to uapi (toolchain people request) - Sysreg updates for new register fields - CPU type info for some Qualcomm Kryo cores" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (72 commits) arm64: mm: Don't use %pK through printk perf/arm_cspmu: Fix missing io.h include arm64: errata: Add newer ARM cores to the spectre_bhb_loop_affected() lists arm64: cputype: Add MIDR_CORTEX_A76AE arm64: errata: Add KRYO 2XX/3XX/4XX silver cores to Spectre BHB safe list arm64: errata: Assume that unknown CPUs _are_ vulnerable to Spectre BHB arm64: errata: Add QCOM_KRYO_4XX_GOLD to the spectre_bhb_k24_list arm64/sysreg: Enforce whole word match for open/close tokens arm64/sysreg: Fix unbalanced closing block arm64: Kconfig: Enable HOTPLUG_SMT arm64: topology: Support SMT control on ACPI based system arch_topology: Support SMT control for OF based system cpu/SMT: Provide a default topology_is_primary_thread() arm64/mm: Define PTDESC_ORDER perf/arm_cspmu: Add PMEVFILT2R support perf/arm_cspmu: Generalise event filtering perf/arm_cspmu: Move register definitons to header arm64/kernel: Always use level 2 or higher for early mappings arm64/mm: Drop PXD_TABLE_BIT arm64/mm: Check pmd_table() in pmd_trans_huge() ...
2025-03-25x86/early_printk: Add support for MMIO-based UARTsDenis Mukhin
During the bring-up of an x86 board, the kernel was crashing before reaching the platform's console driver because of a bug in the firmware, leaving no trace of the boot progress. The only available method to debug the kernel boot process was via the platform's MMIO-based UART, as the board lacked an I/O port-based UART, PCI UART, or functional video output. Then it turned out that earlyprintk= does not have a knob to configure the MMIO-mapped UART. Extend the early printk facility to support platform MMIO-based UARTs on x86 systems, enabling debugging during the system bring-up phase. The command line syntax to enable platform MMIO-based UART is: earlyprintk=mmio,membase[,{nocfg|baudrate}][,keep] Note, the change does not integrate MMIO-based UART support to: arch/x86/boot/early_serial_console.c Also, update kernel parameters documentation with the new syntax and add the missing 'nocfg' setting to the PCI serial cards description. Signed-off-by: Denis Mukhin <dmukhin@ford.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250324-earlyprintk-v3-1-aee7421dc469@ford.com
2025-03-24Merge tag 'x86-core-2025-03-22' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core x86 updates from Ingo Molnar: "x86 CPU features support: - Generate the <asm/cpufeaturemasks.h> header based on build config (H. Peter Anvin, Xin Li) - x86 CPUID parsing updates and fixes (Ahmed S. Darwish) - Introduce the 'setcpuid=' boot parameter (Brendan Jackman) - Enable modifying CPU bug flags with '{clear,set}puid=' (Brendan Jackman) - Utilize CPU-type for CPU matching (Pawan Gupta) - Warn about unmet CPU feature dependencies (Sohil Mehta) - Prepare for new Intel Family numbers (Sohil Mehta) Percpu code: - Standardize & reorganize the x86 percpu layout and related cleanups (Brian Gerst) - Convert the stackprotector canary to a regular percpu variable (Brian Gerst) - Add a percpu subsection for cache hot data (Brian Gerst) - Unify __pcpu_op{1,2}_N() macros to __pcpu_op_N() (Uros Bizjak) - Construct __percpu_seg_override from __percpu_seg (Uros Bizjak) MM: - Add support for broadcast TLB invalidation using AMD's INVLPGB instruction (Rik van Riel) - Rework ROX cache to avoid writable copy (Mike Rapoport) - PAT: restore large ROX pages after fragmentation (Kirill A. Shutemov, Mike Rapoport) - Make memremap(MEMREMAP_WB) map memory as encrypted by default (Kirill A. Shutemov) - Robustify page table initialization (Kirill A. Shutemov) - Fix flush_tlb_range() when used for zapping normal PMDs (Jann Horn) - Clear _PAGE_DIRTY for kernel mappings when we clear _PAGE_RW (Matthew Wilcox) KASLR: - x86/kaslr: Reduce KASLR entropy on most x86 systems, to support PCI BAR space beyond the 10TiB region (CONFIG_PCI_P2PDMA=y) (Balbir Singh) CPU bugs: - Implement FineIBT-BHI mitigation (Peter Zijlstra) - speculation: Simplify and make CALL_NOSPEC consistent (Pawan Gupta) - speculation: Add a conditional CS prefix to CALL_NOSPEC (Pawan Gupta) - RFDS: Exclude P-only parts from the RFDS affected list (Pawan Gupta) System calls: - Break up entry/common.c (Brian Gerst) - Move sysctls into arch/x86 (Joel Granados) Intel LAM support updates: (Maciej Wieczor-Retman) - selftests/lam: Move cpu_has_la57() to use cpuinfo flag - selftests/lam: Skip test if LAM is disabled - selftests/lam: Test get_user() LAM pointer handling AMD SMN access updates: - Add SMN offsets to exclusive region access (Mario Limonciello) - Add support for debugfs access to SMN registers (Mario Limonciello) - Have HSMP use SMN through AMD_NODE (Yazen Ghannam) Power management updates: (Patryk Wlazlyn) - Allow calling mwait_play_dead with an arbitrary hint - ACPI/processor_idle: Add FFH state handling - intel_idle: Provide the default enter_dead() handler - Eliminate mwait_play_dead_cpuid_hint() Build system: - Raise the minimum GCC version to 8.1 (Brian Gerst) - Raise the minimum LLVM version to 15.0.0 (Nathan Chancellor) Kconfig: (Arnd Bergmann) - Add cmpxchg8b support back to Geode CPUs - Drop 32-bit "bigsmp" machine support - Rework CONFIG_GENERIC_CPU compiler flags - Drop configuration options for early 64-bit CPUs - Remove CONFIG_HIGHMEM64G support - Drop CONFIG_SWIOTLB for PAE - Drop support for CONFIG_HIGHPTE - Document CONFIG_X86_INTEL_MID as 64-bit-only - Remove old STA2x11 support - Only allow CONFIG_EISA for 32-bit Headers: - Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI and non-UAPI headers (Thomas Huth) Assembly code & machine code patching: - x86/alternatives: Simplify alternative_call() interface (Josh Poimboeuf) - x86/alternatives: Simplify callthunk patching (Peter Zijlstra) - KVM: VMX: Use named operands in inline asm (Josh Poimboeuf) - x86/hyperv: Use named operands in inline asm (Josh Poimboeuf) - x86/traps: Cleanup and robustify decode_bug() (Peter Zijlstra) - x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> (Uros Bizjak) - Use named operands in inline asm (Uros Bizjak) - Improve performance by using asm_inline() for atomic locking instructions (Uros Bizjak) Earlyprintk: - Harden early_serial (Peter Zijlstra) NMI handler: - Add an emergency handler in nmi_desc & use it in nmi_shootdown_cpus() (Waiman Long) Miscellaneous fixes and cleanups: - by Ahmed S. Darwish, Andy Shevchenko, Ard Biesheuvel, Artem Bityutskiy, Borislav Petkov, Brendan Jackman, Brian Gerst, Dan Carpenter, Dr. David Alan Gilbert, H. Peter Anvin, Ingo Molnar, Josh Poimboeuf, Kevin Brodsky, Mike Rapoport, Lukas Bulwahn, Maciej Wieczor-Retman, Max Grobecker, Patryk Wlazlyn, Pawan Gupta, Peter Zijlstra, Philip Redkin, Qasim Ijaz, Rik van Riel, Thomas Gleixner, Thorsten Blum, Tom Lendacky, Tony Luck, Uros Bizjak, Vitaly Kuznetsov, Xin Li, liuye" * tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (211 commits) zstd: Increase DYNAMIC_BMI2 GCC version cutoff from 4.8 to 11.0 to work around compiler segfault x86/asm: Make asm export of __ref_stack_chk_guard unconditional x86/mm: Only do broadcast flush from reclaim if pages were unmapped perf/x86/intel, x86/cpu: Replace Pentium 4 model checks with VFM ones perf/x86/intel, x86/cpu: Simplify Intel PMU initialization x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headers x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI headers x86/locking/atomic: Improve performance by using asm_inline() for atomic locking instructions x86/asm: Use asm_inline() instead of asm() in clwb() x86/asm: Use CLFLUSHOPT and CLWB mnemonics in <asm/special_insns.h> x86/hweight: Use asm_inline() instead of asm() x86/hweight: Use ASM_CALL_CONSTRAINT in inline asm() x86/hweight: Use named operands in inline asm() x86/stackprotector/64: Only export __ref_stack_chk_guard on CONFIG_SMP x86/head/64: Avoid Clang < 17 stack protector in startup code x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h> x86/runtime-const: Add the RUNTIME_CONST_PTR assembly macro x86/cpu/intel: Limit the non-architectural constant_tsc model checks x86/mm/pat: Replace Intel x86_model checks with VFM ones x86/cpu/intel: Fix fast string initialization for extended Families ...
2025-03-24Merge tag 'rcu-next-v6.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux Pull RCU updates from Boqun Feng: "Documentation: - Add broken-timing possibility to stallwarn.rst - Improve discussion of this_cpu_ptr(), add raw_cpu_ptr() - Document self-propagating callbacks - Point call_srcu() to call_rcu() for detailed memory ordering - Add CONFIG_RCU_LAZY delays to call_rcu() kernel-doc header - Clarify RCU_LAZY and RCU_LAZY_DEFAULT_OFF help text - Remove references to old grace-period-wait primitives srcu: - Introduce srcu_read_{un,}lock_fast(), which is similar to srcu_read_{un,}lock_lite(): avoid smp_mb()s in lock and unlock at the cost of calling synchronize_rcu() in synchronize_srcu() Moreover, by returning the percpu offset of the counter at srcu_read_lock_fast() time, srcu_read_unlock_fast() can avoid extra pointer dereferencing, which makes it faster than srcu_read_{un,}lock_lite() srcu_read_{un,}lock_fast() are intended to replace rcu_read_{un,}lock_trace() if possible RCU torture: - Add get_torture_init_jiffies() to return the start time of the test - Add a test_boost_holdoff module parameter to allow delaying boosting tests when building rcutorture as built-in - Add grace period sequence number logging at the beginning and end of failure/close-call results - Switch to hexadecimal for the expedited grace period sequence number in the rcu_exp_grace_period trace point - Make cur_ops->format_gp_seqs take buffer length - Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool - Complain when invalid SRCU reader_flavor is specified - Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing, which forces SRCU uses atomics even when percpu ops are NMI safe, and use the Kconfig for SRCU lockdep testing Misc: - Split rcu_report_exp_cpu_mult() mask parameter and use for tracing - Remove READ_ONCE() for rdp->gpwrap access in __note_gp_changes() - Fix get_state_synchronize_rcu_full() GP-start detection - Move RCU Tasks self-tests to core_initcall() - Print segment lengths in show_rcu_nocb_gp_state() - Make RCU watch ct_kernel_exit_state() warning - Flush console log from kernel_power_off() - rcutorture: Allow a negative value for nfakewriters - rcu: Update TREE05.boot to test normal synchronize_rcu() - rcu: Use _full() API to debug synchronize_rcu() Make RCU handle PREEMPT_LAZY better: - Fix header guard for rcu_all_qs() - rcu: Rename PREEMPT_AUTO to PREEMPT_LAZY - Update __cond_resched comment about RCU quiescent states - Handle unstable rdp in rcu_read_unlock_strict() - Handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y - osnoise: Provide quiescent states - Adjust rcutorture with possible PREEMPT_RCU=n && PREEMPT_COUNT=y combination - Limit PREEMPT_RCU configurations - Make rcutorture senario TREE07 and senario TREE10 use PREEMPT_LAZY=y" * tag 'rcu-next-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (59 commits) rcutorture: Make scenario TREE07 build CONFIG_PREEMPT_LAZY=y rcutorture: Make scenario TREE10 build CONFIG_PREEMPT_LAZY=y rcu: limit PREEMPT_RCU configurations rcutorture: Update ->extendables check for lazy preemption rcutorture: Update rcutorture_one_extend_check() for lazy preemption osnoise: provide quiescent states rcu: Use _full() API to debug synchronize_rcu() rcu: Update TREE05.boot to test normal synchronize_rcu() rcutorture: Allow a negative value for nfakewriters Flush console log from kernel_power_off() context_tracking: Make RCU watch ct_kernel_exit_state() warning rcu/nocb: Print segment lengths in show_rcu_nocb_gp_state() rcu-tasks: Move RCU Tasks self-tests to core_initcall() rcu: Fix get_state_synchronize_rcu_full() GP-start detection torture: Make SRCU lockdep testing use srcu_read_lock_nmisafe() srcu: Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing rcutorture: Complain when invalid SRCU reader_flavor is specified rcutorture: Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool rcutorture: Make cur_ops->format_gp_seqs take buffer length rcutorture: Add ftrace-compatible timestamp to GP# failure/close-call output ...
2025-03-24Merge tag 'docs-6.15' of git://git.lwn.net/linuxLinus Torvalds
Pull documentation updates from Jonathan Corbet: "It has been a reasonably busy cycle for docs... - Significant changes throughout the tree to bring Python code up to current standards and raise the minimum Python required to 3.9 Much of this is preparatory to replacing the ancient Perl scripts/kernel-doc horror with a slightly less horrifying Python implementation, expected for 6.16 - Update the minimum Sphinx required to 3.4.3, allowing us to remove a bunch of older compatibility code - Rework and improve the generation of the ABI documentation (All of the above done by Mauro) - Lots of translation updates. Alex Shi and Yanteng Si are taking on responsibility for the Chinese translations going forward; that work will still get to you via docs-next - Try to standardize the format for indicating a developer's affiliation in commit tags - Clarify the TAB's role in CoC enforcement actions - Try to spell out the rules for when a commit tag can name another developer without their explicit permission Plus lots of other typo fixes and updates" * tag 'docs-6.15' of git://git.lwn.net/linux: (98 commits) docs/zh_CN: fix spelling mistake docs/Chinese: change the disclaimer words docs/zh_CN: Add snp-tdx-threat-model index Chinese translation docs: driver-api: firmware: clarify userspace requirements docs: clarify rules wrt tagging other people docs: Remove outdated highuid.rst documentation Documentation: dma-buf: heaps: Add heap name definitions docs/.../submit-checklist: Use Documentation/admin-guide/abi.rst for cross-ref of README docs: Correct installation instruction Documentation: kcsan: fix "Plain Accesses and Data Races" URL in kcsan.rst Documentation/CoC: Spell out the TAB role in enforcement decisions Documentation: ocxl.rst: Update consortium site scripts: get_feat.pl: substitute s390x with s390 scripts/kernel-doc: drop dead code for Wcontents_before_sections scripts/kernel-doc: don't add not needed new lines docs: driver-api/infiniband.rst: fix Kerneldoc markup drivers: firewire: firewire-cdev.h: fix identation on a kernel-doc markup drivers: media: intel-ipu3.h: fix identation on a kernel-doc markup include/asm-generic/io.h: fix kerneldoc markup Docs/arch/arm64: Fix spelling in amu.rst ...
2025-03-24Merge tag 'cgroup-for-6.15' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: - Add deprecation info messages to cgroup1-only features - rstat updates including a bug fix and breaking up a critical section to reduce interrupt latency impact - Other misc and doc updates * tag 'cgroup-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: rstat: Cleanup flushing functions and locking cgroup/rstat: avoid disabling irqs for O(num_cpu) mm: Fix a build breakage in memcontrol-v1.c blk-cgroup: Simplify policy files registration cgroup: Update file naming comment cgroup: Add deprecation message to legacy freezer controller mm: Add transformation message for per-memcg swappiness RFC cgroup/cpuset-v1: Add deprecation messages to sched_relax_domain_level cgroup/cpuset-v1: Add deprecation messages to memory_migrate cgroup/cpuset-v1: Add deprecation messages to mem_exclusive and mem_hardwall cgroup: Print message when /proc/cgroups is read on v2-only system cgroup/blkio: Add deprecation messages to reset_stats cgroup/cpuset-v1: Add deprecation messages to memory_spread_page and memory_spread_slab cgroup/cpuset-v1: Add deprecation messages to sched_load_balance and memory_pressure_enabled cgroup, docs: Be explicit about independence of RT_GROUP_SCHED and non-cpu controllers cgroup/rstat: Fix forceidle time in cpu.stat cgroup/misc: Remove unused misc_cg_res_total_usage cgroup/cpuset: Move procfs cpuset attribute under cgroup-v1.c cgroup: update comment about dropping cgroup kn refs
2025-03-24Merge tag 'hardening-v6.15-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull hardening updates from Kees Cook: "As usual, it's scattered changes all over. Patches touching things outside of our traditional areas in the tree have been Acked by maintainers or were trivial changes: - loadpin: remove unsupported MODULE_COMPRESS_NONE (Arulpandiyan Vadivel) - samples/check-exec: Fix script name (Mickaël Salaün) - yama: remove needless locking in yama_task_prctl() (Oleg Nesterov) - lib/string_choices: Sort by function name (R Sundar) - hardening: Allow default HARDENED_USERCOPY to be set at compile time (Mel Gorman) - uaccess: Split out compile-time checks into ucopysize.h - kbuild: clang: Support building UM with SUBARCH=i386 - x86: Enable i386 FORTIFY_SOURCE on Clang 16+ - ubsan/overflow: Rework integer overflow sanitizer option - Add missing __nonstring annotations for callers of memtostr*()/strtomem*() - Add __must_be_noncstr() and have memtostr*()/strtomem*() check for it - Introduce __nonstring_array for silencing future GCC 15 warnings" * tag 'hardening-v6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (26 commits) compiler_types: Introduce __nonstring_array hardening: Enable i386 FORTIFY_SOURCE on Clang 16+ x86/build: Remove -ffreestanding on i386 with GCC ubsan/overflow: Enable ignorelist parsing and add type filter ubsan/overflow: Enable pattern exclusions ubsan/overflow: Rework integer overflow sanitizer option to turn on everything samples/check-exec: Fix script name yama: don't abuse rcu_read_lock/get_task_struct in yama_task_prctl() kbuild: clang: Support building UM with SUBARCH=i386 loadpin: remove MODULE_COMPRESS_NONE as it is no longer supported lib/string_choices: Rearrange functions in sorted order string.h: Validate memtostr*()/strtomem*() arguments more carefully compiler.h: Introduce __must_be_noncstr() nilfs2: Mark on-disk strings as nonstring uapi: stddef.h: Introduce __kernel_nonstring x86/tdx: Mark message.bytes as nonstring string: kunit: Mark nonstring test strings as __nonstring scsi: qla2xxx: Mark device strings as nonstring scsi: mpt3sas: Mark device strings as nonstring scsi: mpi3mr: Mark device strings as nonstring ...
2025-03-24Merge branch 'pm-cpuidle'Rafael J. Wysocki
Merge cpuidle updates for 6.15-rc5, including a menu governor update that is reported to improve some benchmark results quite significantly: - Update the handling of the most recent idle intervals in the menu cpuidle governor to prevent useful information from being discarded by it in some cases and improve the prediction accuracy (Rafael Wysocki). - Make it possible to tell the intel_idle driver to ignore its built-in table of idle states for the given processor, clean up the handling of auto-demotion disabling on Baytrail and Cherrytrail chips in it, and update its MAINTAINERS entry (David Arcari, Artem Bityutskiy, Rafael Wysocki). - Make some cpuidle drivers use for_each_present_cpu() instead of for_each_possible_cpu() during initialization to avoid issues occurring when nosmp or maxcpus=0 are used (Jacky Bai). * pm-cpuidle: cpuidle: Init cpuidle only for present CPUs cpuidle: intel_idle: Update MAINTAINERS intel_idle: introduce 'no_native' module parameter cpuidle: menu: Update documentation after get_typical_interval() changes cpuidle: menu: Avoid discarding useful information cpuidle: menu: Eliminate outliers on both ends of the sample set cpuidle: menu: Tweak threshold use in get_typical_interval() cpuidle: menu: Use one loop for average and variance computations cpuidle: menu: Drop a redundant local variable intel_idle: clean up BYT/CHT auto demotion disable
2025-03-24Merge branch 'pm-cpufreq'Rafael J. Wysocki
Merge cpufreq updates for 6.15-rc1: - Manage sysfs attributes and boost frequencies efficiently from cpufreq core to reduce boilerplate code from drivers (Viresh Kumar). - Minor cleanups to cpufreq drivers (Aaron Kling, Benjamin Schneider, Dhananjay Ugwekar, Imran Shaik, and zuoqian). - Migrate some cpufreq drivers to using for_each_present_cpu() (Jacky Bai). - cpufreq-qcom-hw DT binding fixes (Krzysztof Kozlowski). - Use str_enable_disable() helper in cpufreq_online() (Lifeng Zheng). - Optimize the amd-pstate driver to avoid cases where call paths end up calling the same writes multiple times and needlessly caching variables through code reorganization, locking overhaul and tracing adjustments (Mario Limonciello, Dhananjay Ugwekar). - Make it possible to avoid enabling capacity-aware scheduling (CAS) in the intel_pstate driver and relocate a check for out-of-band (OOB) platform handling in it to make it detect OOB before checking HWP availability (Rafael Wysocki). - Fix dbs_update() to avoid inadvertent conversions of negative integer values to unsigned int which causes CPU frequency selection to be inaccurate in some cases when the "conservative" cpufreq governor is in use (Jie Zhan). * pm-cpufreq: (91 commits) dt-bindings: cpufreq: cpufreq-qcom-hw: Narrow properties on SDX75, SA8775p and SM8650 dt-bindings: cpufreq: cpufreq-qcom-hw: Drop redundant minItems:1 dt-bindings: cpufreq: cpufreq-qcom-hw: Add missing constraint for interrupt-names dt-bindings: cpufreq: cpufreq-qcom-hw: Add QCS8300 compatible cpufreq: Init cpufreq only for present CPUs cpufreq: tegra186: Share policy per cluster cpufreq/amd-pstate: Drop actions in amd_pstate_epp_cpu_offline() cpufreq/amd-pstate: Stop caching EPP cpufreq/amd-pstate: Rework CPPC enabling cpufreq/amd-pstate: Drop debug statements for policy setting cpufreq/amd-pstate: Update cppc_req_cached for shared mem EPP writes cpufreq/amd-pstate: Move all EPP tracing into *_update_perf and *_set_epp functions cpufreq/amd-pstate: Cache CPPC request in shared mem case too cpufreq/amd-pstate: Replace all AMD_CPPC_* macros with masks cpufreq/amd-pstate-ut: Adjust variable scope cpufreq/amd-pstate-ut: Run on all of the correct CPUs cpufreq/amd-pstate-ut: Drop SUCCESS and FAIL enums cpufreq/amd-pstate-ut: Allow lowest nonlinear and lowest to be the same cpufreq/amd-pstate-ut: Use _free macro to free put policy cpufreq/amd-pstate: Drop `cppc_cap1_cached` ...
2025-03-21cgroup: docs: add pswpin and pswpout items in cgroup v2 docHao Jia
The commit 15ff4d409e1a ("mm/memcontrol: add per-memcg pgpgin/pswpin counter") introduced the pswpin and pswpout items in the memory.stat of cgroup v2. Therefore, update them accordingly in the cgroup-v2 documentation. Link: https://lkml.kernel.org/r/20250318075833.90615-3-jiahao.kernel@gmail.com Fixes: 15ff4d409e1a ("mm/memcontrol: add per-memcg pgpgin/pswpin counter") Signed-off-by: Hao Jia <jiahao1@lixiang.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-21mm: vmscan: split proactive reclaim statistics from direct reclaim statisticsHao Jia
Patch series "Adding Proactive Memory Reclaim Statistics". These two patches are related to proactive memory reclaim. Patch 1 Split proactive reclaim statistics from direct reclaim counters and introduces new counters: pgsteal_proactive, pgdemote_proactive, and pgscan_proactive. Patch 2 Adds pswpin and pswpout items to the cgroup-v2 documentation. This patch (of 2): In proactive memory reclaim scenarios, it is necessary to accurately track proactive reclaim statistics to dynamically adjust the frequency and amount of memory being reclaimed proactively. Currently, proactive reclaim is included in direct reclaim statistics, which can make these direct reclaim statistics misleading. Therefore, separate proactive reclaim memory from the direct reclaim counters by introducing new counters: pgsteal_proactive, pgdemote_proactive, and pgscan_proactive, to avoid confusion with direct reclaim. Link: https://lkml.kernel.org/r/20250318075833.90615-1-jiahao.kernel@gmail.com Link: https://lkml.kernel.org/r/20250318075833.90615-2-jiahao.kernel@gmail.com Signed-off-by: Hao Jia <jiahao1@lixiang.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-20printk/panic: Add option to allow non-panic CPUs to write to the ring buffer.Donghyeok Choe
Commit 779dbc2e78d7 ("printk: Avoid non-panic CPUs writing to ringbuffer") aimed to isolate panic-related messages. However, when panic() itself malfunctions, messages from non-panic CPUs become crucial for debugging. While commit bcc954c6caba ("printk/panic: Allow cpu backtraces to be written into ringbuffer during panic") enables non-panic CPU backtraces, it may not provide sufficient diagnostic information. Introduce the "debug_non_panic_cpus" command-line option, enabling non-panic CPU messages to be stored in the ring buffer during a panic. This also prevents discarding non-finalized messages from non-panic CPUs during console flushing, providing a more comprehensive view of system state during critical failures. Link: https://lore.kernel.org/all/Z8cLEkqLL2IOyNIj@pathway/ Signed-off-by: Donghyeok Choe <d7271.choe@samsung.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20250318022320.2428155-1-d7271.choe@samsung.com [pmladek@suse.com: Added documentation, added module_parameter, removed printk_ prefix.] Tested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
2025-03-19Documentation/kernel-parameters: Add riscv unaligned speed parametersAndrew Jones
Document riscv parameters used to select scalar and vector unaligned access speeds. Signed-off-by: Andrew Jones <ajones@ventanamicro.com> Link: https://lore.kernel.org/r/20250304120014.143628-18-ajones@ventanamicro.com Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
2025-03-19x86/rfds: Exclude P-only parts from the RFDS affected listPawan Gupta
The affected CPU table (cpu_vuln_blacklist) marks Alderlake and Raptorlake P-only parts affected by RFDS. This is not true because only E-cores are affected by RFDS. With the current family/model matching it is not possible to differentiate the unaffected parts, as the affected and unaffected hybrid variants have the same model number. Add a cpu-type match as well for such parts so as to exclude P-only parts being marked as affected. Note, family/model and cpu-type enumeration could be inaccurate in virtualized environments. In a guest affected status is decided by RFDS_NO and RFDS_CLEAR bits exposed by VMMs. Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20250311-add-cpu-type-v8-5-e8514dcaaff2@linux.intel.com
2025-03-19Merge tag 'v6.14-rc7' into x86/core, to pick up fixesIngo Molnar
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2025-03-17mm: page_alloc: defrag_modeJohannes Weiner
The page allocator groups requests by migratetype to stave off fragmentation. However, in practice this is routinely defeated by the fact that it gives up *before* invoking reclaim and compaction - which may well produce suitable pages. As a result, fragmentation of physical memory is a common ongoing process in many load scenarios. Fragmentation deteriorates compaction's ability to produce huge pages. Depending on the lifetime of the fragmenting allocations, those effects can be long-lasting or even permanent, requiring drastic measures like forcible idle states or even reboots as the only reliable ways to recover the address space for THP production. In a kernel build test with supplemental THP pressure, the THP allocation rate steadily declines over 15 runs: thp_fault_alloc 61988 56474 57258 50187 52388 55409 52925 47648 43669 40621 36077 41721 36685 34641 33215 This is a hurdle in adopting THP in any environment where hosts are shared between multiple overlapping workloads (cloud environments), and rarely experience true idle periods. To make THP a reliable and predictable optimization, there needs to be a stronger guarantee to avoid such fragmentation. Introduce defrag_mode. When enabled, reclaim/compaction is invoked to its full extent *before* falling back. Specifically, ALLOC_NOFRAGMENT is enforced on the allocator fastpath and the reclaiming slowpath. For now, fallbacks are permitted to avert OOMs. There is a plan to add defrag_mode=2 to prefer OOMs over fragmentation, but this requires additional prep work in compaction and the reserve management to make it ready for all possible allocation contexts. The following test results are from a kernel build with periodic bursts of THP allocations, over 15 runs: vanilla defrag_mode=1 @claimer[unmovable]: 189 103 @claimer[movable]: 92 103 @claimer[reclaimable]: 207 61 @pollute[unmovable from movable]: 25 0 @pollute[unmovable from reclaimable]: 28 0 @pollute[movable from unmovable]: 38835 0 @pollute[movable from reclaimable]: 147136 0 @pollute[reclaimable from unmovable]: 178 0 @pollute[reclaimable from movable]: 33 0 @steal[unmovable from movable]: 11 0 @steal[unmovable from reclaimable]: 5 0 @steal[reclaimable from unmovable]: 107 0 @steal[reclaimable from movable]: 90 0 @steal[movable from reclaimable]: 354 0 @steal[movable from unmovable]: 130 0 Both types of polluting fallbacks are eliminated in this workload. Interestingly, whole block conversions are reduced as well. This is because once a block is claimed for a type, its empty space remains available for future allocations, instead of being padded with fallbacks; this allows the native type to group up instead of spreading out to new blocks. The assumption in the allocator has been that pollution from movable allocations is less harmful than from other types, since they can be reclaimed or migrated out should the space be needed. However, since fallbacks occur *before* reclaim/compaction is invoked, movable pollution will still cause non-movable allocations to spread out and claim more blocks. Without fragmentation, THP rates hold steady with defrag_mode=1: thp_fault_alloc 32478 20725 45045 32130 14018 21711 40791 29134 34458 45381 28305 17265 22584 28454 30850 While the downward trend is eliminated, the keen reader will of course notice that the baseline rate is much smaller than the vanilla kernel's to begin with. This is due to deficiencies in how reclaim and compaction are currently driven: ALLOC_NOFRAGMENT increases the extent to which smaller allocations are competing with THPs for pageblocks, while making no effort themselves to reclaim or compact beyond their own request size. This effect already exists with the current usage of ALLOC_NOFRAGMENT, but is amplified by defrag_mode insisting on whole block stealing much more strongly. Subsequent patches will address defrag_mode reclaim strategy to raise the THP success baseline above the vanilla kernel. Link: https://lkml.kernel.org/r/20250313210647.1314586-4-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17Docs/admin-guide/mm/damon/usage: update for {core,ops}_filters directoriesSeongJae Park
Document {core,ops}_filters directories on usage document. Link: https://lkml.kernel.org/r/20250305222733.59089-9-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17mm: stop maintaining the per-page mapcount of large folios ↵David Hildenbrand
(CONFIG_NO_PAGE_MAPCOUNT) Everything is in place to stop using the per-page mapcounts in large folios: the mapcount of tail pages will always be logically 0 (-1 value), just like it currently is for hugetlb folios already, and the page mapcount of the head page is either 0 (-1 value) or contains a page type (e.g., hugetlb). Maintaining _nr_pages_mapped without per-page mapcounts is impossible, so that one also has to go with CONFIG_NO_PAGE_MAPCOUNT. There are two remaining implications: (1) Per-node, per-cgroup and per-lruvec stats of "NR_ANON_MAPPED" ("mapped anonymous memory") and "NR_FILE_MAPPED" ("mapped file memory"): As soon as any page of the folio is mapped -- folio_mapped() -- we now account the complete folio as mapped. Once the last page is unmapped -- !folio_mapped() -- we account the complete folio as unmapped. This implies that ... * "AnonPages" and "Mapped" in /proc/meminfo and /sys/devices/system/node/*/meminfo * cgroup v2: "anon" and "file_mapped" in "memory.stat" and "memory.numa_stat" * cgroup v1: "rss" and "mapped_file" in "memory.stat" and "memory.numa_stat ... can now appear higher than before. But note that these folios do consume that memory, simply not all pages are actually currently mapped. It's worth nothing that other accounting in the kernel (esp. cgroup charging on allocation) is not affected by this change. [why oh why is "anon" called "rss" in cgroup v1] (2) Detecting partial mappings Detecting whether anon THPs are partially mapped gets a bit more unreliable. As long as a single MM maps such a large folio ("exclusively mapped"), we can reliably detect it. Especially before fork() / after a short-lived child process quit, we will detect partial mappings reliably, which is the common case. In essence, if the average per-page mapcount in an anon THP is < 1, we know for sure that we have a partial mapping. However, as soon as multiple MMs are involved, we might miss detecting partial mappings: this might be relevant with long-lived child processes. If we have a fully-mapped anon folio before fork(), once our child processes and our parent all unmap (zap/COW) the same pages (but not the complete folio), we might not detect the partial mapping. However, once the child processes quit we would detect the partial mapping. How relevant this case is in practice remains to be seen. Swapout/migration will likely mitigate this. In the future, RMAP walkers could check for that for that case (e.g., when collecting access bits during reclaim) and simply flag them for deferred-splitting. Link: https://lkml.kernel.org/r/20250303163014.1128035-21-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Andy Lutomirks^H^Hski <luto@kernel.org> Cc: Borislav Betkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Michal Koutn <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: tejun heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17fs/proc/task_mmu: remove per-page mapcount dependency for PM_MMAP_EXCLUSIVE ↵David Hildenbrand
(CONFIG_NO_PAGE_MAPCOUNT) Let's implement an alternative when per-page mapcounts in large folios are no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT. PM_MMAP_EXCLUSIVE will now be set if folio_likely_mapped_shared() is true -- when the folio is considered "mapped shared", including when it once was "mapped shared" but no longer is, as documented. This might result in and under-indication of "exclusively mapped", which is considered better than over-indicating it: under-estimating the USS (Unique Set Size) is better than over-estimating it. As an alternative, we could simply remove that flag with CONFIG_NO_PAGE_MAPCOUNT completely, but there might be value to it. So, let's keep it like that and document the behavior. Link: https://lkml.kernel.org/r/20250303163014.1128035-18-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Andy Lutomirks^H^Hski <luto@kernel.org> Cc: Borislav Betkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Michal Koutn <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: tejun heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17fs/proc/page: remove per-page mapcount dependency for /proc/kpagecount ↵David Hildenbrand
(CONFIG_NO_PAGE_MAPCOUNT) Let's implement an alternative when per-page mapcounts in large folios are no longer maintained -- soon with CONFIG_NO_PAGE_MAPCOUNT. For large folios, we'll return the per-page average mapcount within the folio, whereby we round to the closest integer when calculating the average: however, we'll always return at least 1 if the folio is mapped. So assuming a folio with 512 pages, the average would be: * 0 if not pages are mapped * 1 if there are 1 .. 767 per-page mappings * 2 if there are 767 .. 1279 per-page mappings ... For hugetlb folios and for large folios that are fully mapped into all address spaces, there is no change. We'll make use of this helper in other context next. As an alternative, we could simply return 0 for non-hugetlb large folios, or disable this legacy interface with CONFIG_NO_PAGE_MAPCOUNT. But the information exposed by this interface can still be valuable, and frequently we deal with fully-mapped large folios where the average corresponds to the actual page mapcount. So we'll leave it like this for now and document the new behavior. Note: this interface is likely not very relevant for performance. If ever required, we could try doing a rather expensive rmap walk to collect precisely how often this folio page is mapped. Link: https://lkml.kernel.org/r/20250303163014.1128035-17-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Cc: Andy Lutomirks^H^Hski <luto@kernel.org> Cc: Borislav Betkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lance Yang <ioworker0@gmail.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Michal Koutn <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: tejun heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17docs: Remove outdated highuid.rst documentationkth
The highuid.rst document describes a transition that is outdated and no longer relevant. Additionally, it references filesystems (ncpfs and smbfs), which have been removed or replaced. Suggested-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Kang Taeho <kangtaeho2456@gmail.com> Link: https://lore.kernel.org/r/20250313145650.278346-1-kangtaeho2456@gmail.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2025-03-17printk: Add an option to allow ttynull to be a default console deviceAdam Simonelli
The new option is CONFIG_NULL_TTY_DEFAULT_CONSOLE. if enabled, and CONFIG_VT is disabled, ttynull will become the default primary console device. ttynull will be the only console device usually with this option enabled. Some architectures do call add_preferred_console() which may add another console though. Motivation: Many distributions ship with CONFIG_VT enabled. On tested desktop hardware if CONFIG_VT is disabled, the default console device falls back to /dev/ttyS0 instead of /dev/tty. This could cause issues in user space, and hardware problems: 1. The user space issues include the case where /dev/ttyS0 is disconnected, and the TCGETS ioctl, which some user space libraries use as a probe to determine if a file is a tty, is called on /dev/console and fails. Programs that call isatty() on /dev/console and get an incorrect false value may skip expected logging to /dev/console. 2. The hardware issues include the case if a user has a science instrument or other device connected to the /dev/ttyS0 port, and they were to upgrade to a kernel that is disabling the CONFIG_VT option, kernel logs will then be sent to the device connected to /dev/ttyS0 unless they edit their kernel command line manually. The new CONFIG_NULL_TTY_DEFAULT_CONSOLE option will give users and distribution maintainers an option to avoid this. Disabling CONFIG_VT and enabling CONFIG_NULL_TTY_DEFAULT_CONSOLE will ensure the default kernel console behavior is not dependent on hardware configuration by default, and avoid unexpected new behavior on devices connected to the /dev/ttyS0 serial port. Reviewed-by: Petr Mladek <pmladek@suse.com> Tested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Adam Simonelli <adamsimonelli@gmail.com> Link: https://lore.kernel.org/r/20250314160749.3286153-2-adamsimonelli@gmail.com [pmladek@suse.com: Fixed indentation of the commit message.] Signed-off-by: Petr Mladek <pmladek@suse.com>
2025-03-17mm: hugetlb: add hugetlb_alloc_threads cmdline optionThomas Prescher
Add a command line option that enables control of how many threads should be used to allocate huge pages. [akpm@linux-foundation.org: tidy up a comment] Link: https://lkml.kernel.org/r/20250227-hugepage-parameter-v2-2-7db8c6dc0453@cyberus-technology.de Signed-off-by: Thomas Prescher <thomas.prescher@cyberus-technology.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Muchun Song <muchun.song@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17Docs/admin-guide/mm/damon/usage: add intervals_goal directory on the hierarchySeongJae Park
Document DAMON sysfs interface usage for DAMON sampling and aggregation intervals auto-tuning. Link: https://lkml.kernel.org/r/20250303221726.484227-9-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16reboot: add support for configuring emergency hardware protection actionAhmad Fatoum
We currently leave the decision of whether to shutdown or reboot to protect hardware in an emergency situation to the individual drivers. This works out in some cases, where the driver detecting the critical failure has inside knowledge: It binds to the system management controller for example or is guided by hardware description that defines what to do. In the general case, however, the driver detecting the issue can't know what the appropriate course of action is and shouldn't be dictating the policy of dealing with it. Therefore, add a global hw_protection toggle that allows the user to specify whether shutdown or reboot should be the default action when the driver doesn't set policy. This introduces no functional change yet as hw_protection_trigger() has no callers, but these will be added in subsequent commits. [arnd@arndb.de: hide unused hw_protection_attr] Link: https://lkml.kernel.org/r/20250224141849.1546019-1-arnd@kernel.org Link: https://lkml.kernel.org/r/20250217-hw_protection-reboot-v3-7-e1c09b090c0c@pengutronix.de Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org> Cc: Benson Leung <bleung@chromium.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Fabio Estevam <festevam@denx.de> Cc: Guenter Roeck <groeck@chromium.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Girdwood <lgirdwood@gmail.com> Cc: Lukasz Luba <lukasz.luba@arm.com> Cc: Mark Brown <broonie@kernel.org> Cc: Matteo Croce <teknoraver@meta.com> Cc: Matti Vaittinen <mazziesaccount@gmail.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Rob Herring (Arm) <robh@kernel.org> Cc: Rui Zhang <rui.zhang@intel.com> Cc: Sascha Hauer <kernel@pengutronix.de> Cc: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16fs/proc/task_mmu: add guard region bit to pagemapLorenzo Stoakes
Patch series "fs/proc/task_mmu: add guard region bit to pagemap". Currently there is no means of determining whether a given page in a mapping range is designated a guard region (as installed via madvise() using the MADV_GUARD_INSTALL flag). This is generally not an issue, but in some instances users may wish to determine whether this is the case. This series adds this ability via /proc/$pid/pagemap, updates the documentation and adds a self test to assert that this functions correctly. This patch (of 2): Currently there is no means by which users can determine whether a given page in memory is in fact a guard region, that is having had the MADV_GUARD_INSTALL madvise() flag applied to it. This is intentional, as to provide this information in VMA metadata would contradict the intent of the feature (providing a means to change fault behaviour at a page table level rather than a VMA level), and would require VMA metadata operations to scan page tables, which is unacceptable. In many cases, users have no need to reflect and determine what regions have been designated guard regions, as it is the user who has established them in the first place. But in some instances, such as monitoring software, or software that relies upon being able to ascertain the nature of mappings within a remote process for instance, it becomes useful to be able to determine which pages have the guard region marker applied. This patch makes use of an unused pagemap bit (58) to provide this information. This patch updates the documentation at the same time as making the change such that the implementation of the feature and the documentation of it are tied together. Link: https://lkml.kernel.org/r/cover.1740139449.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/521d99c08b975fb06a1e7201e971cc24d68196d1.1740139449.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16zram: remove max_comp_streams device attrSergey Senozhatsky
max_comp_streams device attribute has been defunct since May 2016 when zram switched to per-CPU compression streams, remove it. Link: https://lkml.kernel.org/r/20250303022425.285971-5-senozhatsky@chromium.org Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Hillf Danton <hdanton@sina.com> Cc: Kairui Song <ryncsn@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Yosry Ahmed <yosry.ahmed@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16mm/hugetlb: add hugetlb_cma_only cmdline optionFrank van der Linden
Add an option to force hugetlb gigantic pages to be allocated using CMA only (if hugetlb_cma is enabled). This avoids a fallback to allocation from the rest of system memory if the CMA allocation fails. This makes the size of hugetlb_cma a hard upper boundary for gigantic hugetlb page allocations. This is useful because, with a large CMA area, the kernel's unmovable allocations will have less room to work with and it is undesirable for new hugetlb gigantic page allocations to be done from that remaining area. It will eat in to the space available for unmovable allocations, leading to unwanted system behavior (OOMs because the kernel fails to do unmovable allocations). So, with this enabled, an administrator can force a hard upper bound for runtime gigantic page allocations, and have more predictable system behavior. Link: https://lkml.kernel.org/r/20250228182928.2645936-26-fvdl@google.com Signed-off-by: Frank van der Linden <fvdl@google.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dan Carpenter <dan.carpenter@linaro.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16mm/hugetlb: convert cmdline parameters from setup to earlyFrank van der Linden
Convert the cmdline parameters (hugepagesz, hugepages, default_hugepagesz and hugetlb_free_vmemmap) to early parameters. Since parse_early_param might run before MMU setups on some platforms (powerpc), validation of huge page sizes as specified in command line parameters would fail. So instead, for the hstate-related values, just record the them and parse them on demand, from hugetlb_bootmem_alloc. The allocation of hugetlb bootmem pages is now done in hugetlb_bootmem_alloc, which is called explicitly at the start of mm_core_init(). core_initcall would be too late, as that happens with memblock already torn down. This change will allow earlier allocation and initialization of bootmem hugetlb pages later on. No functional change intended. Link: https://lkml.kernel.org/r/20250228182928.2645936-8-fvdl@google.com Signed-off-by: Frank van der Linden <fvdl@google.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dan Carpenter <dan.carpenter@linaro.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16mm, cma: support multiple contiguous ranges, if requestedFrank van der Linden
Currently, CMA manages one range of physically contiguous memory. Creation of larger CMA areas with hugetlb_cma may run in to gaps in physical memory, so that they are not able to allocate that contiguous physical range from memblock when creating the CMA area. This can happen, for example, on an AMD system with > 1TB of memory, where there will be a gap just below the 1TB (40bit DMA) line. If you have set aside most of memory for potential hugetlb CMA allocation, cma_declare_contiguous_nid will fail. hugetlb_cma doesn't need the entire area to be one physically contiguous range. It just cares about being able to get physically contiguous chunks of a certain size (e.g. 1G), and it is fine to have the CMA area backed by multiple physical ranges, as long as it gets 1G contiguous allocations. Multi-range support is implemented by introducing an array of ranges, instead of just one big one. Each range has its own bitmap. Effectively, the allocate and release operations work as before, just per-range. So, instead of going through one large bitmap, they now go through a number of smaller ones. The maximum number of supported ranges is 8, as defined in CMA_MAX_RANGES. Since some current users of CMA expect a CMA area to just use one physically contiguous range, only allow for multiple ranges if a new interface, cma_declare_contiguous_nid_multi, is used. The other interfaces will work like before, creating only CMA areas with 1 range. cma_declare_contiguous_nid_multi works as follows, mimicking the default "bottom-up, above 4G" reservation approach: 0) Try cma_declare_contiguous_nid, which will use only one region. If this succeeds, return. This makes sure that for all the cases that currently work, the behavior remains unchanged even if the caller switches from cma_declare_contiguous_nid to cma_declare_contiguous_nid_multi. 1) Select the largest free memblock ranges above 4G, with a maximum number of CMA_MAX_RANGES. 2) If we did not find at most CMA_MAX_RANGES that add up to the total size requested, return -ENOMEM. 3) Sort the selected ranges by base address. 4) Reserve them bottom-up until we get what we wanted. Link: https://lkml.kernel.org/r/20250228182928.2645936-3-fvdl@google.com Signed-off-by: Frank van der Linden <fvdl@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dan Carpenter <dan.carpenter@linaro.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Muchun Song <muchun.song@linux.dev> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin (Cruise) <roman.gushchin@linux.dev> Cc: Usama Arif <usamaarif642@gmail.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16Docs/damon: move DAMOS filter type names and meaning to design docSeongJae Park
DAMON sysfs usage doc is describing DAMOS filter type names and their meanings in short. The design doc is providing the short meaning and detailed descriptions, too. This is unnecessary duplicates and confuses where to document new DAMOS filter types and features. Move the details from usage to design doc. Link: https://lkml.kernel.org/r/20250218223708.53437-4-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16Docs/admin-guide/mm/damon/usage: document hugepage_size filter typeUsama Arif
This includes both the 'hugepage_size' filter type and the min/max files used to decide range of sizes to filter on. Link: https://lkml.kernel.org/r/20250211124437.278873-5-usamaarif642@gmail.com Signed-off-by: Usama Arif <usamaarif642@gmail.com> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-16mm: zbud: remove zbudYosry Ahmed
The zbud compressed pages allocator is rarely used, most users use zsmalloc. zbud consumes much more memory (only stores 1 or 2 compressed pages per physical page). The only advantage of zbud is a marginal performance improvement that by no means justify the memory overhead. Historically, zsmalloc had significantly worse latency than zbud and z3fold but offered better memory savings. This is no longer the case as shown by a simple recent analysis [1]. In a kernel build test on tmpfs in a limited cgroup, zbud 2-3% less time than zsmalloc, but at the cost of using ~32% more memory (1.5G vs 1.13G). The tradeoff does not make sense for zbud in any practical scenario. The only alleged advantage of zbud is not having the dependency on CONFIG_MMU, but CONFIG_SWAP already depends on CONFIG_MMU anyway, and zbud is only used by zswap. Remove zbud after z3fold's removal, leaving zsmalloc as the one and only zpool allocator. Leave the removal of the zpool API (and its associated config options) to a followup cleanup after no more allocators show up. Deprecating zbud for a few cycles before removing it was initially proposed [2], like z3fold was marked as deprecated for 2 cycles [3]. However, Johannes rightfully pointed out that the 2 cycles is too short for most downstream consumers, and z3fold was deprecated first only as a courtesy anyway. [1]https://lore.kernel.org/lkml/CAJD7tkbRF6od-2x_L8-A1QL3=2Ww13sCj4S3i4bNndqF+3+_Vg@mail.gmail.com/ [2]https://lore.kernel.org/lkml/Z5gdnSX5Lv-nfjQL@google.com/ [3]https://lore.kernel.org/lkml/20240904233343.933462-1-yosryahmed@google.com/ Link: https://lkml.kernel.org/r/20250129180633.3501650-3-yosry.ahmed@linux.dev Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: WANG Xuerui <kernel@xen0n.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-13ext4: update the descriptions of data_err=abort and data_err=ignoreBaokun Li
We now print error messages in ext4_end_bio() when page writeback encounters an error. If data_err=abort is set, the journal will also be aborted in a kworker. This means that we now check all Buffer I/O in all modes and decide whether to abort the journal based on the data_err option. Therefore, we remove the ordered mode restriction in the descriptions of data_err=abort and data_err=ignore. Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Zhang Yi <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20250122110533.4116662-8-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2025-03-12docs: Correct installation instructionI Hsin Cheng
Ammend missing "install" operation keyword after "apt-get", and fix "build-essentials" to "build-essential". Signed-off-by: I Hsin Cheng <richard120310@gmail.com> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20250306030708.8133-1-richard120310@gmail.com
2025-03-12PNP: Remove prehistoric deadcodeDr. David Alan Gilbert
pnp_remove_card() is currently unused, it has been since it was added in 2003's BKrev: 3e6d3f19XSmESWEZnNEReEJOJW5SOw pnp_unregister_protocol() is currently unused, it has been since it was added in 2002's BKrev: 3df0cf6d4FVUKndhbfxjL7pksw5PGA Remove them, and pnp_remove_card_device() and __pnp_remove_device() which are now no longer used. Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org> Link: https://patch.msgid.link/20250307214936.74504-1-linux@treblig.org Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-03-11cgroup: Add deprecation message to legacy freezer controllerMichal Koutný
As explained in the commit 76f969e8948d8 ("cgroup: cgroup v2 freezer"), the original freezer is imperfect, some users may unwittingly rely on it when there exists the alternative of v2. Print a message when it happens and explain that in the docs. Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-11mm: Add transformation message for per-memcg swappinessMichal Koutný
The concept of per-memcg swappiness has never landed well in memcg for cgroup v2. Add a message to users who use it on v1 hierarchy. Decreased swappiness transforms to memory.swap.max=0 whereas increased swappiness transforms into active memory.reclaim operation. Link: https://lore.kernel.org/r/1577252208-32419-1-git-send-email-teawater@gmail.com/ Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-09Merge tag 'kbuild-fixes-v6.14-3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - Use the specified $(LD) when building userprogs with Clang - Pass the correct target triple when compile-testing UAPI headers with Clang - Fix pacman-pkg build error with KBUILD_OUTPUT * tag 'kbuild-fixes-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: install-extmod-build: Fix build when specifying KBUILD_OUTPUT docs: Kconfig: fix defconfig description kbuild: hdrcheck: fix cross build with clang kbuild: userprogs: use correct lld when linking through clang
2025-03-06taint: Add TAINT_FWCTLJason Gunthorpe
Requesting a fwctl scope of access that includes mutating device debug data will cause the kernel to be tainted. Changing the device operation through things in the debug scope may cause the device to malfunction in undefined ways. This should be reflected in the TAINT flags to help any debuggers understand that something has been done. Link: https://patch.msgid.link/r/4-v5-642aa0c94070+4447f-fwctl_jgg@nvidia.com Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Dave Jiang <dave.jiang@intel.com> Reviewed-by: Shannon Nelson <shannon.nelson@amd.com> Tested-by: Dave Jiang <dave.jiang@intel.com> Tested-by: Shannon Nelson <shannon.nelson@amd.com> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2025-03-05cgroup, docs: Be explicit about independence of RT_GROUP_SCHED and non-cpu ↵Shashank Balaji
controllers The cgroup v2 cpu controller has a limitation that if CONFIG_RT_GROUP_SCHED is enabled, the cpu controller can be enabled only if all the realtime processes are in the root cgroup. The other controllers have no such restriction. They can be used for the resource control of realtime processes irrespective of whether CONFIG_RT_GROUP_SCHED is enabled or not. Signed-off-by: Shashank Balaji <shashank.mahadasyam@sony.com> Acked-by: Waiman Long <longman@redhat.com> Acked-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-05docs: Kconfig: fix defconfig descriptionSatoru Takeuchi
Commit 2a86f6612164 ("kbuild: use KBUILD_DEFCONFIG as the fallback for DEFCONFIG_LIST") removed arch/$ARCH/defconfig; however, the document has not been updated to reflect this change yet. Signed-off-by: Satoru Takeuchi <satoru.takeuchi@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-03-03x86/bugs: Make spectre user default depend on MITIGATION_SPECTRE_V2Breno Leitao
Change the default value of spectre v2 in user mode to respect the CONFIG_MITIGATION_SPECTRE_V2 config option. Currently, user mode spectre v2 is set to auto (SPECTRE_V2_USER_CMD_AUTO) by default, even if CONFIG_MITIGATION_SPECTRE_V2 is disabled. Set the spectre_v2 value to auto (SPECTRE_V2_USER_CMD_AUTO) if the Spectre v2 config (CONFIG_MITIGATION_SPECTRE_V2) is enabled, otherwise set the value to none (SPECTRE_V2_USER_CMD_NONE). Important to say the command line argument "spectre_v2_user" overwrites the default value in both cases. When CONFIG_MITIGATION_SPECTRE_V2 is not set, users have the flexibility to opt-in for specific mitigations independently. In this scenario, setting spectre_v2= will not enable spectre_v2_user=, and command line options spectre_v2_user and spectre_v2 are independent when CONFIG_MITIGATION_SPECTRE_V2=n. Signed-off-by: Breno Leitao <leitao@debian.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Kaplan <David.Kaplan@amd.com> Link: https://lore.kernel.org/r/20241031-x86_bugs_last_v2-v2-2-b7ff1dab840e@debian.org
2025-02-28mm: security: Allow default HARDENED_USERCOPY to be set at compile timeMel Gorman
HARDENED_USERCOPY defaults to on if enabled at compile time. Allow hardened_usercopy= default to be set at compile time similar to init_on_alloc= and init_on_free=. The intent is that hardening options that can be disabled at runtime can set their default at build time. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Link: https://lore.kernel.org/r/20250123221115.19722-3-mgorman@techsingularity.net Signed-off-by: Kees Cook <kees@kernel.org>
2025-02-27x86/mm: Drop support for CONFIG_HIGHPTEArnd Bergmann
With the maximum amount of RAM now 4GB, there is very little point to still have PTE pages in highmem. Drop this for simplification. The only other architecture supporting HIGHPTE is 32-bit arm, and once that feature is removed as well, the highpte logic can be dropped from common code as well. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250226213714.4040853-8-arnd@kernel.org
2025-02-27x86/mm: Remove CONFIG_HIGHMEM64G supportArnd Bergmann
HIGHMEM64G support was added in linux-2.3.25 to support (then) high-end Pentium Pro and Pentium III Xeon servers with more than 4GB of addressing, NUMA and PCI-X slots started appearing. I have found no evidence of this ever being used in regular dual-socket servers or consumer devices, all the users seem obsolete these days, even by i386 standards: - Support for NUMA servers (NUMA-Q, IBM x440, unisys) was already removed ten years ago. - 4+ socket non-NUMA servers based on Intel 450GX/450NX, HP F8 and ServerWorks ServerSet/GrandChampion could theoretically still work with 8GB, but these were exceptionally rare even 20 years ago and would have usually been equipped with than the maximum amount of RAM. - Some SKUs of the Celeron D from 2004 had 64-bit mode fused off but could still work in a Socket 775 mainboard designed for the later Core 2 Duo and 8GB. Apparently most BIOSes at the time only allowed 64-bit CPUs. - The rare Xeon LV "Sossaman" came on a few motherboards with registered DDR2 memory support up to 16GB. - In the early days of x86-64 hardware, there was sometimes the need to run a 32-bit kernel to work around bugs in the hardware drivers, or in the syscall emulation for 32-bit userspace. This likely still works but there should never be a need for this any more. PAE mode is still required to get access to the 'NX' bit on Atom 'Pentium M' and 'Core Duo' CPUs. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250226213714.4040853-6-arnd@kernel.org