linux/Documentation/admin-guide/kernel-parameters.txt, branch v5.6

ACPI: watchdog: Allow disabling WDAT at boot

2020-02-10T01:23:50Z

In case the WDAT interface is broken, give the user an option to ignore it to let a native driver bind to the watchdog device instead. Signed-off-by: Jean Delvare Acked-by: Mika Westerberg Signed-off-by: Rafael J. Wysocki

Merge tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2020-02-06T07:12:11Z

Pull tracing updates from Steven Rostedt: - Added new "bootconfig". This looks for a file appended to initrd to add boot config options, and has been discussed thoroughly at Linux Plumbers. Very useful for adding kprobes at bootup. Only enabled if "bootconfig" is on the real kernel command line. - Created dynamic event creation. Merges common code between creating synthetic events and kprobe events. - Rename perf "ring_buffer" structure to "perf_buffer" - Rename ftrace "ring_buffer" structure to "trace_buffer" Had to rename existing "trace_buffer" to "array_buffer" - Allow trace_printk() to work withing (some) tracing code. - Sort of tracing configs to be a little better organized - Fixed bug where ftrace_graph hash was not being protected properly - Various other small fixes and clean ups * tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (88 commits) bootconfig: Show the number of nodes on boot message tools/bootconfig: Show the number of bootconfig nodes bootconfig: Add more parse error messages bootconfig: Use bootconfig instead of boot config ftrace: Protect ftrace_graph_hash with ftrace_sync ftrace: Add comment to why rcu_dereference_sched() is open coded tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu tracing: Annotate ftrace_graph_hash pointer with __rcu bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline tracing: Use seq_buf for building dynevent_cmd string tracing: Remove useless code in dynevent_arg_pair_add() tracing: Remove check_arg() callbacks from dynevent args tracing: Consolidate some synth_event_trace code tracing: Fix now invalid var_ref_vals assumption in trace action tracing: Change trace_boot to use synth_event interface tracing: Move tracing selftests to bottom of menu tracing: Move mmio tracer config up with the other tracers tracing: Move tracing test module configs together tracing: Move all function tracing configs together tracing: Documentation for in-kernel synthetic event API ...

bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline

2020-02-05T09:22:43Z

As the bootconfig is appended to the initrd it is not as easy to modify as the kernel command line. If there's some issue with the kernel, and the developer wants to boot a pristine kernel, it should not be needed to modify the initrd to remove the bootconfig for a single boot. As bootconfig is silently added (if the admin does not know where to look they may not know it's being loaded). It should be explicitly added to the kernel cmdline. The loading of the bootconfig is only done if "bootconfig" is on the kernel command line. This will let admins know that the kernel command line is extended. Note, after adding printk()s for when the size is too great or the checksum is wrong, exposed that the current method always looked for the boot config, and if this size and checksum matched, it would parse it (as if either is wrong a printk has been added to show this). It's better to only check this if the boot config is asked to be looked for. Link: https://lore.kernel.org/r/CAHk-=wjfjO+h6bQzrTf=YCZA53Y3EDyAs3Z4gEsT7icA3u_Psw@mail.gmail.com Acked-by: Masami Hiramatsu Suggested-by: Linus Torvalds Signed-off-by: Steven Rostedt (VMware)

s390/boot: add dfltcc= kernel command line parameter

2020-01-31T18:30:40Z

Add the new kernel command line parameter 'dfltcc=' to configure s390 zlib hardware support. Format: { on | off | def_only | inf_only | always } on: s390 zlib hardware support for compression on level 1 and decompression (default) off: No s390 zlib hardware support def_only: s390 zlib hardware support for deflate only (compression on level 1) inf_only: s390 zlib hardware support for inflate only (decompression) always: Same as 'on' but ignores the selected compression level always using hardware support (used for debugging) Link: http://lkml.kernel.org/r/20200103223334.20669-5-zaslonko@linux.ibm.com Signed-off-by: Mikhail Zaslonko Cc: Chris Mason Cc: Christian Borntraeger Cc: David Sterba Cc: Eduard Shishkin Cc: Heiko Carstens Cc: Ilya Leoshkevich Cc: Josef Bacik Cc: Richard Purdie Cc: Vasily Gorbik Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-01-28T17:03:40Z

Pull EFI updates from Ingo Molnar: "The main changes in this cycle were: - Cleanup of the GOP [graphics output] handling code in the EFI stub - Complete refactoring of the mixed mode handling in the x86 EFI stub - Overhaul of the x86 EFI boot/runtime code - Increase robustness for mixed mode code - Add the ability to disable DMA at the root port level in the EFI stub - Get rid of RWX mappings in the EFI memory map and page tables, where possible - Move the support code for the old EFI memory mapping style into its only user, the SGI UV1+ support code. - plus misc fixes, updates, smaller cleanups. ... and due to interactions with the RWX changes, another round of PAT cleanups make a guest appearance via the EFI tree - with no side effects intended" * 'efi-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (75 commits) efi/x86: Disable instrumentation in the EFI runtime handling code efi/libstub/x86: Fix EFI server boot failure efi/x86: Disallow efi=old_map in mixed mode x86/boot/compressed: Relax sed symbol type regex for LLVM ld.lld efi/x86: avoid KASAN false positives when accessing the 1: 1 mapping efi: Fix handling of multiple efi_fake_mem= entries efi: Fix efi_memmap_alloc() leaks efi: Add tracking for dynamically allocated memmaps efi: Add a flags parameter to efi_memory_map efi: Fix comment for efi_mem_type() wrt absent physical addresses efi/arm: Defer probe of PCIe backed efifb on DT systems efi/x86: Limit EFI old memory map to SGI UV machines efi/x86: Avoid RWX mappings for all of DRAM efi/x86: Don't map the entire kernel text RW for mixed mode x86/mm: Fix NX bit clearing issue in kernel_map_pages_in_pgd efi/libstub/x86: Fix unused-variable warning efi/libstub/x86: Use mandatory 16-byte stack alignment in mixed mode efi/libstub/x86: Use const attribute for efi_is_64bit() efi: Allow disabling PCI busmastering on bridges during boot efi/x86: Allow translating 64-bit arguments for mixed mode calls ...

Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-01-28T16:46:13Z

Pull RCU updates from Ingo Molnar: "The RCU changes in this cycle were: - Expedited grace-period updates - kfree_rcu() updates - RCU list updates - Preemptible RCU updates - Torture-test updates - Miscellaneous fixes - Documentation updates" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits) rcu: Remove unused stop-machine #include powerpc: Remove comment about read_barrier_depends() .mailmap: Add entries for old paulmck@kernel.org addresses srcu: Apply *_ONCE() to ->srcu_last_gp_end rcu: Switch force_qs_rnp() to for_each_leaf_node_cpu_mask() rcu: Move rcu_{expedited,normal} definitions into rcupdate.h rcu: Move gp_state_names[] and gp_state_getname() to tree_stall.h rcu: Remove the declaration of call_rcu() in tree.h rcu: Fix tracepoint tracking RCU CPU kthread utilization rcu: Fix harmless omission of "CONFIG_" from #if condition rcu: Avoid tick_dep_set_cpu() misordering rcu: Provide wrappers for uses of ->rcu_read_lock_nesting rcu: Use READ_ONCE() for ->expmask in rcu_read_unlock_special() rcu: Clear ->rcu_read_unlock_special only once rcu: Clear .exp_hint only when deferred quiescent state has been reported rcu: Rename some instance of CONFIG_PREEMPTION to CONFIG_PREEMPT_RCU rcu: Remove kfree_call_rcu_nobatch() rcu: Remove kfree_rcu() special casing and lazy-callback handling rcu: Add support for debug_objects debugging for kfree_rcu() rcu: Add multiple in-flight batches of kfree_rcu() work ...

Merge tag 'irq-core-2020-01-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-01-28T01:22:21Z

Pull irq updates from Thomas Gleixner: "The interrupt departement provides: - A mechanism to shield isolated tasks from managed interrupts: The affinity of managed interrupts is completely controlled by the kernel and user space has no influence on them. The reason is that the automatically assigned affinity correlates to the multi-queue CPU handling of block devices. If the generated affinity mask spaws both housekeeping and isolated CPUs the interrupt could be routed to an isolated CPU which would then be disturbed by I/O submitted by a housekeeping CPU. The new mechamism ensures that as long as one housekeeping CPU is online in the assigned affinity mask the interrupt is routed to a housekeeping CPU. If there is no online housekeeping CPU in the affinity mask, then the interrupt is routed to an isolated CPU to keep the device queue intact, but unless the isolated CPU submits I/O by itself these interrupts are not raised. - A small addon to the device tree irqdomain core code to avoid duplication in irq chip drivers - Conversion of the SiFive PLIC to hierarchical domains - The usual pile of new irq chip drivers: SiFive GPIO, Aspeed SCI, NXP INTMUX, Meson A1 GPIO - The first cut of support for the new ARM GICv4.1 - The usual pile of fixes and improvements in core and driver code" * tag 'irq-core-2020-01-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits) genirq, sched/isolation: Isolate from handling managed interrupts irqchip/gic-v4.1: Allow direct invalidation of VLPIs irqchip/gic-v4.1: Suppress per-VLPI doorbell irqchip/gic-v4.1: Add VPE INVALL callback irqchip/gic-v4.1: Add VPE eviction callback irqchip/gic-v4.1: Add VPE residency callback irqchip/gic-v4.1: Add mask/unmask doorbell callbacks irqchip/gic-v4.1: Plumb skeletal VPE irqchip irqchip/gic-v4.1: Implement the v4.1 flavour of VMOVP irqchip/gic-v4.1: Don't use the VPE proxy if RVPEID is set irqchip/gic-v4.1: Implement the v4.1 flavour of VMAPP irqchip/gic-v4.1: VPE table (aka GICR_VPROPBASER) allocation irqchip/gic-v3: Add GICv4.1 VPEID size discovery irqchip/gic-v3: Detect GICv4.1 supporting RVPEID irqchip/gic-v3-its: Fix get_vlpi_map() breakage with doorbells irqdomain: Fix a memory leak in irq_domain_push_irq() irqchip: Add NXP INTMUX interrupt multiplexer support dt-bindings: interrupt-controller: Add binding for NXP INTMUX interrupt multiplexer irqchip: Define EXYNOS_IRQ_COMBINER irqchip/meson-gpio: Add support for meson a1 SoCs ...

rcu: Remove kfree_call_rcu_nobatch()

2020-01-24T18:24:31Z

Now that the kfree_rcu() special-casing has been removed from tree RCU, this commit removes kfree_call_rcu_nobatch() since it is no longer needed. Signed-off-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney

rcuperf: Add kfree_rcu() performance Tests

2020-01-24T18:24:31Z

This test runs kfree_rcu() in a loop to measure performance of the new kfree_rcu() batching functionality. The following table shows results when booting with arguments: rcuperf.kfree_loops=20000 rcuperf.kfree_alloc_num=8000 rcuperf.kfree_rcu_test=1 rcuperf.kfree_no_batch=X rcuperf.kfree_no_batch=X # Grace Periods Test Duration (s) X=1 (old behavior) 9133 11.5 X=0 (new behavior) 1732 12.5 On a 16 CPU system with the above boot parameters, we see that the total number of grace periods that elapse during the test drops from 9133 when not batching to 1732 when batching (a 5X improvement). The kfree_rcu() flood itself slows down a bit when batching, though, as shown. Note that the active memory consumption during the kfree_rcu() flood does increase to around 200-250MB due to the batching (from around 50MB without batching). However, this memory consumption is relatively constant. In other words, the system is able to keep up with the kfree_rcu() load. The memory consumption comes down considerably if KFREE_DRAIN_JIFFIES is increased from HZ/50 to HZ/80. A later patch will reduce memory consumption further by using multiple lists. Also, when running the test, please disable CONFIG_DEBUG_PREEMPT and CONFIG_PROVE_RCU for realistic comparisons with/without batching. Signed-off-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney

genirq, sched/isolation: Isolate from handling managed interrupts

2020-01-22T15:29:49Z

The affinity of managed interrupts is completely handled in the kernel and cannot be changed via the /proc/irq/* interfaces from user space. As the kernel tries to spread out interrupts evenly accross CPUs on x86 to prevent vector exhaustion, it can happen that a managed interrupt whose affinity mask contains both isolated and housekeeping CPUs is routed to an isolated CPU. As a consequence IO submitted on a housekeeping CPU causes interrupts on the isolated CPU. Add a new sub-parameter 'managed_irq' for 'isolcpus' and the corresponding logic in the interrupt affinity selection code. The subparameter indicates to the interrupt affinity selection logic that it should try to avoid the above scenario. This isolation is best effort and only effective if the automatically assigned interrupt mask of a device queue contains isolated and housekeeping CPUs. If housekeeping CPUs are online then such interrupts are directed to the housekeeping CPU so that IO submitted on the housekeeping CPU cannot disturb the isolated CPU. If a queue's affinity mask contains only isolated CPUs then this parameter has no effect on the interrupt routing decision, though interrupts are only happening when tasks running on those isolated CPUs submit IO. IO submitted on housekeeping CPUs has no influence on those queues. If the affinity mask contains both housekeeping and isolated CPUs, but none of the contained housekeeping CPUs is online, then the interrupt is also routed to an isolated CPU. Interrupts are only delivered when one of the isolated CPUs in the affinity mask submits IO. If one of the contained housekeeping CPUs comes online, the CPU hotplug logic migrates the interrupt automatically back to the upcoming housekeeping CPU. Depending on the type of interrupt controller, this can require that at least one interrupt is delivered to the isolated CPU in order to complete the migration. [ tglx: Removed unused parameter, added and edited comments/documentation and rephrased the changelog so it contains more details. ] Signed-off-by: Ming Lei Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20200120091625.17912-1-ming.lei@redhat.com