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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
2025-02-27x86/smp: Drop 32-bit "bigsmp" machine supportArnd Bergmann
The x86-32 kernel used to support multiple platforms with more than eight logical CPUs, from the 1999-2003 timeframe: Sequent NUMA-Q, IBM Summit, Unisys ES7000 and HP F8. Support for all except the latter was dropped back in 2014, leaving only the F8 based DL740 and DL760 G2 machines in this catery, with up to eight single-core Socket-603 Xeon-MP processors with hyperthreading. Like the already removed machines, the HP F8 servers at the time cost upwards of $100k in typical configurations, but were quickly obsoleted by their 64-bit Socket-604 cousins and the AMD Opteron. Earlier servers with up to 8 Pentium Pro or Xeon processors remain fully supported as they had no hyperthreading. Similarly, the more common 4-socket Xeon-MP machines with hyperthreading using Intel or ServerWorks chipsets continue to work without this, and all the multi-core Xeon processors also run 64-bit kernels. While the "bigsmp" support can also be used to run on later 64-bit machines (including VM guests), it seems best to discourage that and get any remaining users to update their kernels to 64-bit builds on these. As a side-effect of this, there is also no more need to support NUMA configurations on 32-bit x86, as all true 32-bit NUMA platforms are already gone. 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/20250226213714.4040853-3-arnd@kernel.org
2025-02-26docs: Remove reference to removed CBE_CPUFREQ_SPU_GOVERNORMichael Ellerman
Remove a reference to CBE_CPUFREQ_SPU_GOVERNOR which has been removed. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/20241218105523.416573-20-mpe@ellerman.id.au
2025-02-26x86/bugs: KVM: Add support for SRSO_MSR_FIXBorislav Petkov
Add support for CPUID Fn8000_0021_EAX[31] (SRSO_MSR_FIX). If this bit is 1, it indicates that software may use MSR BP_CFG[BpSpecReduce] to mitigate SRSO. Enable BpSpecReduce to mitigate SRSO across guest/host boundaries. Switch back to enabling the bit when virtualization is enabled and to clear the bit when virtualization is disabled because using a MSR slot would clear the bit when the guest is exited and any training the guest has done, would potentially influence the host kernel when execution enters the kernel and hasn't VMRUN the guest yet. More detail on the public thread in Link below. Co-developed-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lore.kernel.org/r/20241202120416.6054-1-bp@kernel.org
2025-02-25tracing: Add traceoff_after_boot optionSteven Rostedt
Sometimes tracing is used to debug issues during the boot process. Since the trace buffer has a limited amount of storage, it may be prudent to disable tracing after the boot is finished, otherwise the critical information may be overwritten. With this option, the main tracing buffer will be turned off at the end of the boot process. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Borislav Petkov <bp@alien8.de> Link: https://lore.kernel.org/20250208103017.48a7ec83@batman.local.home Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-02-25Merge branch 'cpuidle-menu'Rafael J. Wysocki
This work had been triggered by a report that commit 0611a640e60a ("eventpoll: prefer kfree_rcu() in __ep_remove()") had caused the critical-jOPS metric of the SPECjbb 2015 benchmark [1] to drop by around 50% even though it generally reduced kernel overhead. Indeed, it was found during further investigation that the total interrupt rate while running the SPECjbb workload had fallen as a result of that commit by 55% and the local timer interrupt rate had fallen by almost 80%. That turned out to cause the menu cpuidle governor to select the deepest idle state supplied by the cpuidle driver (intel_idle) much more often which added significantly more idle state latency to the workload and that led to the decrease of the critical-jOPS score. Interestingly enough, this problem was not visible when the teo cpuidle governor was used instead of menu, so it appeared to be specific to the latter. CPU wakeup event statistics collected while running the workload indicated that the menu governor was effectively ignoring non- timer wakeup information and all of its idle state selection decisions appeared to be based on timer wakeups only. Thus, it appeared that the reduction of the local timer interrupt rate caused the governor to predict a idle duration much more often while running the workload and the deepest idle state was selected significantly more often as a result of that. A subsequent inspection of the get_typical_interval() function in the menu governor indicated that it might return UINT_MAX too often which then caused the governor's decisions to be based entirely on information related to timers. Generally speaking, UINT_MAX is returned by get_typical_interval() if it cannot make a prediction based on the most recent idle intervals data with sufficiently high confidence, but at least in some cases this means that useful information is not taken into account at all which may lead to significant idle state selection mistakes. Moreover, this is not really unlikely to happen. One issue with get_typical_interval() is that, when it eliminates outliers from the sample set in an attempt to reduce the standard deviation (and so improve the prediction confidence), it does that by dropping high-end samples only, while samples at the low end of the set are retained. However, the samples at the low end very well may be the outliers and they should be eliminated from the sample set instead of the high-end samples. Accordingly, the likelihood of making a meaningful idle duration prediction can be improved by making it also eliminate low-end samples if they are farther from the average than high-end samples. Another issue is that get_typical_interval() gives up after eliminating 1/4 of the samples if the standard deviation is still not as low as desired (within 1/6 of the average or within 20 us if the average is close to 0), but the remaining samples in the set still represent useful information at that point and discarding them altogether may lead to suboptimal idle state selection. For instance, the largest idle duration value in the get_typical_interval() data set is the maximum idle duration observed recently and it is likely that the upcoming idle duration will not exceed it. Therefore, in the absence of a better choice, this value can be used as an upper bound on the target residency of the idle state to select. * cpuidle-menu: 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
2025-02-25intel_idle: introduce 'no_native' module parameterDavid Arcari
Since commit 18734958e9bf ("intel_idle: Use ACPI _CST for processor models without C-state tables") the intel_idle driver has had the ability to use the ACPI _CST to populate C-states when the processor model is not recognized. However, even when the processor model is recognized (native mode) there are cases where it is useful to make the driver ignore the per-CPU idle states in lieu of ACPI C-states (such as specific application performance). Add a new 'no_native' module parameter to provide this functionality. Signed-off-by: David Arcari <darcari@redhat.com> Link: https://patch.msgid.link/20250220151120.1131122-1-darcari@redhat.com Reviewed-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> [ rjw: Spell CPU in capitals ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-02-25cpuidle: menu: Update documentation after get_typical_interval() changesRafael J. Wysocki
The documentation of the menu cpuidle governor needs to be updated to match the code behavior after some changes made recently. No functional impact. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Christian Loehle <christian.loehle@arm.com> Link: https://patch.msgid.link/4998484.31r3eYUQgx@rjwysocki.net [ rjw: More specific subject, two typos fixed in the changelog ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-02-24coredump: Only sort VMAs when core_sort_vma sysctl is setKees Cook
The sorting of VMAs by size in commit 7d442a33bfe8 ("binfmt_elf: Dump smaller VMAs first in ELF cores") breaks elfutils[1]. Instead, sort based on the setting of the new sysctl, core_sort_vma, which defaults to 0, no sorting. Reported-by: Michael Stapelberg <michael@stapelberg.ch> Closes: https://lore.kernel.org/all/20250218085407.61126-1-michael@stapelberg.de/ [1] Fixes: 7d442a33bfe8 ("binfmt_elf: Dump smaller VMAs first in ELF cores") Signed-off-by: Kees Cook <kees@kernel.org>
2025-02-21Fix typos in admin-guide/gpioMaksimilijan Marosevic
Fixing typos. Signed-off-by: Maksimilijan Marosevic <maksimilijan.marosevic@proton.me> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20250218193822.1031-1-maksimilijan.marosevic@proton.me
2025-02-21media: admin-guide: add mgb4 GMSL modules variants descriptionMartin Tůma
Document the (new) mgb4 GMSL modules variants. Signed-off-by: Martin Tůma <martin.tuma@digiteqautomotive.com> Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
2025-02-21Documentation: media: fix spelling error in the HDMI CEC documentationChandra Pratap
Correct the erroneous spelling of 'responsible' in Documentation/admin-guide/media/cec.rst. This fixes all errors pointed out by codespell in the file. Signed-off-by: Chandra Pratap <chandrapratap3519@gmail.com> Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
2025-02-18docs: thunderbolt: Allow creating cross-references for ABIMauro Carvalho Chehab
Now that Documentation/ABI is processed by automarkup, let it generate cross-references for the corresponding ABI file. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/a655e770e1446f91088f579b79ae890a19771119.1739254867.git.mchehab+huawei@kernel.org
2025-02-18docs: iostats: Rewrite intro, remove outdated formatsDavid Reaver
The introduction discussed stat file formats for very old kernel versions, which obscured key information that readers may find useful. Additionally, the example file contents and the reference to "15 fields" did not account for the flush fields added in b6866318657 ("block: add iostat counters for flush requests") [1]. Rewrite the introduction to focus only on the current kernel's disk I/O stat file formats. Also, clean up wording for conciseness. Link: https://lore.kernel.org/lkml/157433282607.7928.5202409984272248322.stgit@buzz/T/ [1] Signed-off-by: David Reaver <me@davidreaver.com> Link: https://lore.kernel.org/r/20250215180114.157948-1-me@davidreaver.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2025-02-18Documentation/kernel-parameters: fix typo in description of reserve_memMike Rapoport (Microsoft)
The format description of reserve_mem uses [KNG] as units, rather than [KMG]. Fix it. Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20250218070845.3769520-1-rppt@kernel.org
2025-02-18cpufreq: intel_pstate: Make it possible to avoid enabling CASRafael J. Wysocki
Capacity-aware scheduling (CAS) is enabled by default by intel_pstate on hybrid systems without SMT, but in some usage scenarios it may be more attractive to place tasks for maximum CPU performance regardless of the extra cost in terms of energy, which is the case on such systems when CAS is not enabled, so introduce a command line option to forbid intel_pstate to enable CAS. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by:Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Link: https://patch.msgid.link/2781262.mvXUDI8C0e@rjwysocki.net
2025-02-17cpufreq: Introduce an optional cpuinfo_avg_freq sysfs entryBeata Michalska
Currently the CPUFreq core exposes two sysfs attributes that can be used to query current frequency of a given CPU(s): namely cpuinfo_cur_freq and scaling_cur_freq. Both provide slightly different view on the subject and they do come with their own drawbacks. cpuinfo_cur_freq provides higher precision though at a cost of being rather expensive. Moreover, the information retrieved via this attribute is somewhat short lived as frequency can change at any point of time making it difficult to reason from. scaling_cur_freq, on the other hand, tends to be less accurate but then the actual level of precision (and source of information) varies between architectures making it a bit ambiguous. The new attribute, cpuinfo_avg_freq, is intended to provide more stable, distinct interface, exposing an average frequency of a given CPU(s), as reported by the hardware, over a time frame spanning no more than a few milliseconds. As it requires appropriate hardware support, this interface is optional. Note that under the hood, the new attribute relies on the information provided by arch_freq_get_on_cpu, which, up to this point, has been feeding data for scaling_cur_freq attribute, being the source of ambiguity when it comes to interpretation. This has been amended by restoring the intended behavior for scaling_cur_freq, with a new dedicated config option to maintain status quo for those, who may need it. CC: Jonathan Corbet <corbet@lwn.net> CC: Thomas Gleixner <tglx@linutronix.de> CC: Ingo Molnar <mingo@redhat.com> CC: Borislav Petkov <bp@alien8.de> CC: Dave Hansen <dave.hansen@linux.intel.com> CC: H. Peter Anvin <hpa@zytor.com> CC: Phil Auld <pauld@redhat.com> CC: x86@kernel.org CC: linux-doc@vger.kernel.org Signed-off-by: Beata Michalska <beata.michalska@arm.com> Reviewed-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com> Reviewed-by: Sumit Gupta <sumitg@nvidia.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Rafael J. Wysocki <rafael@kernel.org> Link: https://lore.kernel.org/r/20250131162439.3843071-3-beata.michalska@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2025-02-13docs: ABI: move README contents to the topMauro Carvalho Chehab
The ABI documentation looks a little bit better if it starts with the contents of the README is placed at the beginning. Move it to the beginning of the ABI chapter. While here, improve the README text and change the title that will be shown at the html/pdf output to be coherent with both ABI file contents and with the generated documentation output. Suggested-by: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/20250211055809.1898623-1-mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2025-02-10docs: admin-guide/abi: split files from symbolsMauro Carvalho Chehab
Now that get_abi has gained support for filtering its output, split ABI symbols from files at the html output. That makes pages smaller and easier to navigate. As an additional bonus, as it will paralelize files handling, it gives an additional performance improvement. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/30e3cf2a8aeef23ca889de60a90f7de141e0dc0e.1739182025.git.mchehab+huawei@kernel.org
2025-02-10docs: sphinx/kernel_abi: parse ABI files only onceMauro Carvalho Chehab
Right now, the logic parses ABI files on 4 steps, one for each directory. While this is fine in principle, by doing that, not all symbol cross-references will be created. Change the logic to do the parsing only once in order to get a global dictionary to be used when creating ABI cross-references. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/5205c53838b6ea25f4cdd4cc1e3d17c0141e75a6.1739182025.git.mchehab+huawei@kernel.org
2025-02-10docs: use get_abi.py for ABI generationMauro Carvalho Chehab
Use the new script instead of the old one when generating ABI docs. For now, execute it via exec. Future changes will better integrate it by using the class defined there directly. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/e7fcb121c0612c94f6f54f0d742cd3a26a46cd7d.1739182025.git.mchehab+huawei@kernel.org
2025-02-10docs: admin-guide: abi: add SPDX tags to ABI filesMauro Carvalho Chehab
Such files are missing SPDX tags containing the licensing information. Add them. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/8c7bfe676e7349ea2d1930bf918d54e27d15ae9e.1739182025.git.mchehab+huawei@kernel.org
2025-02-07platform/x86: samsung-galaxybook: Add samsung-galaxybook driverJoshua Grisham
Add a new driver for Samsung Galaxy Book series notebook devices with the following features: - Keyboard backlight control - Battery hook for installing power supply extension to add charge control end threshold - Controller for Samsung's performance modes using the platform profile interface - Adds firmware-attributes to control various system features - Handles various hotkeys and notifications Signed-off-by: Joshua Grisham <josh@joshuagrisham.com> Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> Reviewed-by: Armin Wolf <W_Armin@gmx.de> Link: https://lore.kernel.org/r/20250201105450.193450-1-josh@joshuagrisham.com Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
2025-02-05rcutorture: Add a test_boost_holdoff module parameterPaul E. McKenney
This commit adds a test_boost_holdoff module parameter that tells the RCU priority-boosting tests to wait for the specified number of seconds past the start of the rcutorture test. This can be useful when rcutorture is built into the kernel (as opposed to being modprobed), especially on large systems where early start of RCU priority boosting can delay the boot sequence, which adds a full CPU's worth of load onto the system. This can in turn result in pointless stall warnings. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2025-02-04docs: admin-guide: rename GTK+ to GTKDiego Viola
Upstream calls it "GTK" now, see [1] [1] https://mail.gnome.org/archives/gtk-devel-list/2019-February/msg00000.html Signed-off-by: Diego Viola <diego.viola@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20250204040444.6299-1-diego.viola@gmail.com
2025-02-03dm-crypt: Document integrity_key_size option.Milan Broz
This patch adds documentation for new option introduced in commit 4441686b24a1 ("dm-crypt: Allow to specify the integrity key size as option"). Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-02-03dm-integrity: Document Inline mode for storing integrity dataMilan Broz
This patch adds documentation for new 'I' mode for dm-integrity introduced in commit fb0987682c62 ("dm-integrity: introduce the Inline mode"). Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-02-03dm-verity: Document restart_on_error and panic_on_error optionsMilan Broz
This patch adds documentation for options introduced in commit f811b83879fb ("dm-verity: introduce the options restart_on_error and panic_on_error"). Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2025-02-03ata: libata-core: Add 'external' to the libata.force kernel parameterNiklas Cassel
Commit ae1f3db006b7 ("ata: ahci: do not enable LPM on external ports") changed so that LPM is not enabled on external ports (hotplug-capable or eSATA ports). This is because hotplug and LPM are mutually exclusive, see 7.3.1 Hot Plug Removal Detection and Power Management Interaction in AHCI 1.3.1. This does require that firmware has set the appropate bits (HPCP or ESP) in PxCMD (which is a per port register in the AHCI controller). If the firmware has failed to mark a port as hotplug-capable or eSATA in PxCMD, then there is currently not much a user can do. If LPM is enabled on the port, hotplug insertions and removals will not be detected on that port. In order to allow a user to fix up broken firmware, add 'external' to the libata.force kernel parameter. libata.force can be specified either on the kernel command line, or as a kernel module parameter. For more information, see Documentation/admin-guide/kernel-parameters.txt. Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Link: https://lore.kernel.org/r/20250130133544.219297-4-cassel@kernel.org Signed-off-by: Niklas Cassel <cassel@kernel.org>
2025-01-28Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull KVM/arm64 updates from Will Deacon: "New features: - Support for non-protected guest in protected mode, achieving near feature parity with the non-protected mode - Support for the EL2 timers as part of the ongoing NV support - Allow control of hardware tracing for nVHE/hVHE Improvements, fixes and cleanups: - Massive cleanup of the debug infrastructure, making it a bit less awkward and definitely easier to maintain. This should pave the way for further optimisations - Complete rewrite of pKVM's fixed-feature infrastructure, aligning it with the rest of KVM and making the code easier to follow - Large simplification of pKVM's memory protection infrastructure - Better handling of RES0/RES1 fields for memory-backed system registers - Add a workaround for Qualcomm's Snapdragon X CPUs, which suffer from a pretty nasty timer bug - Small collection of cleanups and low-impact fixes" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (87 commits) arm64/sysreg: Get rid of TRFCR_ELx SysregFields KVM: arm64: nv: Fix doc header layout for timers KVM: arm64: nv: Apply RESx settings to sysreg reset values KVM: arm64: nv: Always evaluate HCR_EL2 using sanitising accessors KVM: arm64: Fix selftests after sysreg field name update coresight: Pass guest TRFCR value to KVM KVM: arm64: Support trace filtering for guests KVM: arm64: coresight: Give TRBE enabled state to KVM coresight: trbe: Remove redundant disable call arm64/sysreg/tools: Move TRFCR definitions to sysreg tools: arm64: Update sysreg.h header files KVM: arm64: Drop pkvm_mem_transition for host/hyp donations KVM: arm64: Drop pkvm_mem_transition for host/hyp sharing KVM: arm64: Drop pkvm_mem_transition for FF-A KVM: arm64: Explicitly handle BRBE traps as UNDEFINED KVM: arm64: vgic: Use str_enabled_disabled() in vgic_v3_probe() arm64: kvm: Introduce nvhe stack size constants KVM: arm64: Fix nVHE stacktrace VA bits mask KVM: arm64: Fix FEAT_MTE in pKVM Documentation: Update the behaviour of "kvm-arm.mode" ...
2025-01-26Merge tag 'mm-stable-2025-01-26-14-59' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "The various patchsets are summarized below. Plus of course many indivudual patches which are described in their changelogs. - "Allocate and free frozen pages" from Matthew Wilcox reorganizes the page allocator so we end up with the ability to allocate and free zero-refcount pages. So that callers (ie, slab) can avoid a refcount inc & dec - "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to use large folios other than PMD-sized ones - "Fix mm/rodata_test" from Petr Tesarik performs some maintenance and fixes for this small built-in kernel selftest - "mas_anode_descend() related cleanup" from Wei Yang tidies up part of the mapletree code - "mm: fix format issues and param types" from Keren Sun implements a few minor code cleanups - "simplify split calculation" from Wei Yang provides a few fixes and a test for the mapletree code - "mm/vma: make more mmap logic userland testable" from Lorenzo Stoakes continues the work of moving vma-related code into the (relatively) new mm/vma.c - "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David Hildenbrand cleans up and rationalizes handling of gfp flags in the page allocator - "readahead: Reintroduce fix for improper RA window sizing" from Jan Kara is a second attempt at fixing a readahead window sizing issue. It should reduce the amount of unnecessary reading - "synchronously scan and reclaim empty user PTE pages" from Qi Zheng addresses an issue where "huge" amounts of pte pagetables are accumulated: https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/ Qi's series addresses this windup by synchronously freeing PTE memory within the context of madvise(MADV_DONTNEED) - "selftest/mm: Remove warnings found by adding compiler flags" from Muhammad Usama Anjum fixes some build warnings in the selftests code when optional compiler warnings are enabled - "mm: don't use __GFP_HARDWALL when migrating remote pages" from David Hildenbrand tightens the allocator's observance of __GFP_HARDWALL - "pkeys kselftests improvements" from Kevin Brodsky implements various fixes and cleanups in the MM selftests code, mainly pertaining to the pkeys tests - "mm/damon: add sample modules" from SeongJae Park enhances DAMON to estimate application working set size - "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn provides some cleanups to memcg's hugetlb charging logic - "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song removes the global swap cgroup lock. A speedup of 10% for a tmpfs-based kernel build was demonstrated - "zram: split page type read/write handling" from Sergey Senozhatsky has several fixes and cleaups for zram in the area of zram_write_page(). A watchdog softlockup warning was eliminated - "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin Brodsky cleans up the pagetable destructor implementations. A rare use-after-free race is fixed - "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes simplifies and cleans up the debugging code in the VMA merging logic - "Account page tables at all levels" from Kevin Brodsky cleans up and regularizes the pagetable ctor/dtor handling. This results in improvements in accounting accuracy - "mm/damon: replace most damon_callback usages in sysfs with new core functions" from SeongJae Park cleans up and generalizes DAMON's sysfs file interface logic - "mm/damon: enable page level properties based monitoring" from SeongJae Park increases the amount of information which is presented in response to DAMOS actions - "mm/damon: remove DAMON debugfs interface" from SeongJae Park removes DAMON's long-deprecated debugfs interfaces. Thus the migration to sysfs is completed - "mm/hugetlb: Refactor hugetlb allocation resv accounting" from Peter Xu cleans up and generalizes the hugetlb reservation accounting - "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino removes a never-used feature of the alloc_pages_bulk() interface - "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park extends DAMOS filters to support not only exclusion (rejecting), but also inclusion (allowing) behavior - "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi introduces a new memory descriptor for zswap.zpool that currently overlaps with struct page for now. This is part of the effort to reduce the size of struct page and to enable dynamic allocation of memory descriptors - "mm, swap: rework of swap allocator locks" from Kairui Song redoes and simplifies the swap allocator locking. A speedup of 400% was demonstrated for one workload. As was a 35% reduction for kernel build time with swap-on-zram - "mm: update mips to use do_mmap(), make mmap_region() internal" from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that mmap_region() can be made MM-internal - "mm/mglru: performance optimizations" from Yu Zhao fixes a few MGLRU regressions and otherwise improves MGLRU performance - "Docs/mm/damon: add tuning guide and misc updates" from SeongJae Park updates DAMON documentation - "Cleanup for memfd_create()" from Isaac Manjarres does that thing - "mm: hugetlb+THP folio and migration cleanups" from David Hildenbrand provides various cleanups in the areas of hugetlb folios, THP folios and migration - "Uncached buffered IO" from Jens Axboe implements the new RWF_DONTCACHE flag which provides synchronous dropbehind for pagecache reading and writing. To permite userspace to address issues with massive buildup of useless pagecache when reading/writing fast devices - "selftests/mm: virtual_address_range: Reduce memory" from Thomas Weißschuh fixes and optimizes some of the MM selftests" * tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) mm/compaction: fix UBSAN shift-out-of-bounds warning s390/mm: add missing ctor/dtor on page table upgrade kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags() tools: add VM_WARN_ON_VMG definition mm/damon/core: use str_high_low() helper in damos_wmark_wait_us() seqlock: add missing parameter documentation for raw_seqcount_try_begin() mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh mm/page_alloc: remove the incorrect and misleading comment zram: remove zcomp_stream_put() from write_incompressible_page() mm: separate move/undo parts from migrate_pages_batch() mm/kfence: use str_write_read() helper in get_access_type() selftests/mm/mkdirty: fix memory leak in test_uffdio_copy() kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags() selftests/mm: virtual_address_range: avoid reading from VM_IO mappings selftests/mm: vm_util: split up /proc/self/smaps parsing selftests/mm: virtual_address_range: unmap chunks after validation selftests/mm: virtual_address_range: mmap() without PROT_WRITE selftests/memfd/memfd_test: fix possible NULL pointer dereference mm: add FGP_DONTCACHE folio creation flag mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue ...
2025-01-25Docs/admin-guide/mm/damon/start: update snapshot exampleSeongJae Park
Two of DAMON user-space tool (damo) commands that are used for examples on DAMON getting started document, namely 'damo show' and 'damo report heats' are deprecated[1,2], and replaced by new commands that provides same functions with unified and simplified user interfaces. Also the example output of 'damo show' is outdated. 'damo schemes' command is not deprecated, but users are recommended to use 'damo start' or 'damo tune' instead. Update the examples to use the replacements, recommendations, and up-to-date output formats. [1] https://git.kernel.org/sj/damo/c/3272e0ac94ecc5e1 [2] https://git.kernel.org/sj/damo/c/da3ec66bbdd9e87d Link: https://lkml.kernel.org/r/20250110185232.54907-5-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Honggyu Kim <honggyu.kim@sk.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Yunjeong Mun <yunjeong.mun@sk.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-25Docs/admin-guide/mm/damon/usage: fix and add missing DAMOS filter sysfs ↵SeongJae Park
files on files hierarchy DAMOS filter directory part of DAMON sysfs files hierarchy on the usage document is wrong. 'memcg_path' file under the directory is wrongly written as 'memcg_id'. Also the directory has 'addr_start', 'addr_end', and 'target_idx' files, but the list is missing those. Fix the wrong name and add missing files. Link: https://lkml.kernel.org/r/20250110185232.54907-4-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Honggyu Kim <honggyu.kim@sk.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Yunjeong Mun <yunjeong.mun@sk.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-25Docs/admin-guide/mm/damon/usage: document DAMOS filter 'allow' sysfs fileSeongJae Park
Update DAMON usage document for the newly added 'allow' sysfs file for DAMOS filters. Link: https://lkml.kernel.org/r/20250109175126.57878-11-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>
2025-01-25Docs/admin-guide/mm/damon/usage: omit DAMOS filter details in favor of ↵SeongJae Park
design doc DAMON usage document is describing some details about DAMOS filters, which are also documented on the design doc. Deduplicate the details in favor of the design doc. Link: https://lkml.kernel.org/r/20250109175126.57878-10-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>
2025-01-25Docs/admin-guide/mm/damon/usage: remove DAMON debugfs interface documentationSeongJae Park
It's time to remove DAMON debugfs interface, which has deprecated long before in February 2023. Read the cover letter of this patch series for more details. Remove DAMON debugfs interface usage documentation, to avoid confusing users with documents for an already removed thing. Link: https://lkml.kernel.org/r/20250106191941.107070-3-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Cc: Alex Shi <alexs@kernel.org> Cc: Brendan Higgins <brendan.higgins@linux.dev> Cc: David Gow <davidgow@google.com> Cc: Hu Haowen <2023002089@link.tyut.edu.cn> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Rae Moar <rmoar@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Yanteng Si <si.yanteng@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-01-25Docs/admin-guide/mm/damon/usage: document sz_filtered_out of scheme tried ↵SeongJae Park
region directories Document the newly added DAMON sysfs interface file for per-scheme-tried region's bytes that passed the operations set handling DAMOS filters. Link: https://lkml.kernel.org/r/20250106193401.109161-16-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>
generated by cgit (git 2.34.1) at 2025-07-16 00:34:25 +0000