kernel/git/stable/linux.git/Documentation/admin-guide/kernel-parameters.txt, branch linux-5.12.y

clocksource: Retry clock read if long delays detected

2021-07-14T14:59:28+00:00

[ Upstream commit db3a34e17433de2390eb80d436970edcebd0ca3e ] When the clocksource watchdog marks a clock as unstable, this might be due to that clock being unstable or it might be due to delays that happen to occur between the reads of the two clocks. Yes, interrupts are disabled across those two reads, but there are no shortage of things that can delay interrupts-disabled regions of code ranging from SMI handlers to vCPU preemption. It would be good to have some indication as to why the clock was marked unstable. Therefore, re-read the watchdog clock on either side of the read from the clock under test. If the watchdog clock shows an excessive time delta between its pair of reads, the reads are retried. The maximum number of retries is specified by a new kernel boot parameter clocksource.max_cswd_read_retries, which defaults to three, that is, up to four reads, one initial and up to three retries. If more than one retry was required, a message is printed on the console (the occasional single retry is expected behavior, especially in guest OSes). If the maximum number of retries is exceeded, the clock under test will be marked unstable. However, the probability of this happening due to various sorts of delays is quite small. In addition, the reason (clock-read delays) for the unstable marking will be apparent. Reported-by: Chris Mason Signed-off-by: Paul E. McKenney Signed-off-by: Thomas Gleixner Acked-by: Feng Tang Link: https://lore.kernel.org/r/20210527190124.440372-1-paulmck@kernel.org Signed-off-by: Sasha Levin

iommu/dma: Resurrect the "forcedac" option

2021-05-14T08:52:45+00:00

[ Upstream commit 3542dcb15cef66c0b9e6c3b33168eb657e0d9520 ] In converting intel-iommu over to the common IOMMU DMA ops, it quietly lost the functionality of its "forcedac" option. Since this is a handy thing both for testing and for performance optimisation on certain platforms, reimplement it under the common IOMMU parameter namespace. For the sake of fixing the inadvertent breakage of the Intel-specific parameter, remove the dmar_forcedac remnants and hook it up as an alias while documenting the transition to the new common parameter. Fixes: c588072bba6b ("iommu/vt-d: Convert intel iommu driver to the iommu ops") Signed-off-by: Robin Murphy Acked-by: Lu Baolu Reviewed-by: John Garry Link: https://lore.kernel.org/r/7eece8e0ea7bfbe2cd0e30789e0d46df573af9b0.1614961776.git.robin.murphy@arm.com Signed-off-by: Joerg Roedel Signed-off-by: Sasha Levin

lib: stackdepot: add support to disable stack depot

2021-02-26T17:41:04+00:00

Add a kernel parameter stack_depot_disable to disable stack depot. So that stack hash table doesn't consume any memory when stack depot is disabled. The use case is CONFIG_PAGE_OWNER without page_owner=on. Without this patch, stackdepot will consume the memory for the hashtable. By default, it's 8M which is never trivial. With this option, in CONFIG_PAGE_OWNER configured system, page_owner=off, stack_depot_disable in kernel command line, we could save the wasted memory for the hashtable. [akpm@linux-foundation.org: fix CONFIG_STACKDEPOT=n build] Link: https://lkml.kernel.org/r/1611749198-24316-2-git-send-email-vjitta@codeaurora.org Signed-off-by: Vinayak Menon Signed-off-by: Vijayanand Jitta Cc: Alexander Potapenko Cc: Minchan Kim Cc: Yogesh Lal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2021-02-25T00:20:38+00:00

Merge misc updates from Andrew Morton: "A few small subsystems and some of MM. 172 patches. Subsystems affected by this patch series: hexagon, scripts, ntfs, ocfs2, vfs, and mm (slab-generic, slab, slub, debug, pagecache, swap, memcg, pagemap, mprotect, mremap, page-reporting, vmalloc, kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction, mempolicy, oom-kill, hugetlbfs, and migration)" * emailed patches from Andrew Morton : (172 commits) mm/migrate: remove unneeded semicolons hugetlbfs: remove unneeded return value of hugetlb_vmtruncate() hugetlbfs: fix some comment typos hugetlbfs: correct some obsolete comments about inode i_mutex hugetlbfs: make hugepage size conversion more readable hugetlbfs: remove meaningless variable avoid_reserve hugetlbfs: correct obsolete function name in hugetlbfs_read_iter() hugetlbfs: use helper macro default_hstate in init_hugetlbfs_fs hugetlbfs: remove useless BUG_ON(!inode) in hugetlbfs_setattr() hugetlbfs: remove special hugetlbfs_set_page_dirty() mm/hugetlb: change hugetlb_reserve_pages() to type bool mm, oom: fix a comment in dump_task() mm/mempolicy: use helper range_in_vma() in queue_pages_test_walk() numa balancing: migrate on fault among multiple bound nodes mm, compaction: make fast_isolate_freepages() stay within zone mm/compaction: fix misbehaviors of fast_find_migrateblock() mm/compaction: correct deferral logic for proactive compaction mm/compaction: remove duplicated VM_BUG_ON_PAGE !PageLocked mm/compaction: remove rcu_read_lock during page compaction z3fold: simplify the zhdr initialization code in init_z3fold_page() ...

mm, slub: remove slub_memcg_sysfs boot param and CONFIG_SLUB_MEMCG_SYSFS_ON

2021-02-24T21:38:27+00:00

The boot param and config determine the value of memcg_sysfs_enabled, which is unused since commit 10befea91b61 ("mm: memcg/slab: use a single set of kmem_caches for all allocations") as there are no per-memcg kmem caches anymore. Link: https://lkml.kernel.org/r/20210127124745.7928-1-vbabka@suse.cz Signed-off-by: Vlastimil Babka Reviewed-by: David Hildenbrand Acked-by: Roman Gushchin Acked-by: David Rientjes Reviewed-by: Miaohe Lin Cc: Christoph Lameter Cc: Pekka Enberg Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge tag 'sfi-removal-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

2021-02-24T18:35:29+00:00

Pull Simple Firmware Interface (SFI) support removal from Rafael Wysocki: "Drop support for depercated platforms using SFI, drop the entire support for SFI that has been long deprecated too and make some janitorial changes on top of that (Andy Shevchenko)" * tag 'sfi-removal-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: x86/platform/intel-mid: Update Copyright year and drop file names x86/platform/intel-mid: Remove unused header inclusion in intel-mid.h x86/platform/intel-mid: Drop unused __intel_mid_cpu_chip and Co. x86/platform/intel-mid: Get rid of intel_scu_ipc_legacy.h x86/PCI: Describe @reg for type1_access_ok() x86/PCI: Get rid of custom x86 model comparison sfi: Remove framework for deprecated firmware cpufreq: sfi-cpufreq: Remove driver for deprecated firmware media: atomisp: Remove unused header mfd: intel_msic: Remove driver for deprecated platform x86/apb_timer: Remove driver for deprecated platform x86/platform/intel-mid: Remove unused leftovers (vRTC) x86/platform/intel-mid: Remove unused leftovers (msic) x86/platform/intel-mid: Remove unused leftovers (msic_thermal) x86/platform/intel-mid: Remove unused leftovers (msic_power_btn) x86/platform/intel-mid: Remove unused leftovers (msic_gpio) x86/platform/intel-mid: Remove unused leftovers (msic_battery) x86/platform/intel-mid: Remove unused leftovers (msic_ocd) x86/platform/intel-mid: Remove unused leftovers (msic_audio) platform/x86: intel_scu_wdt: Drop mistakenly added const

Merge tag 'driver-core-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2021-02-24T18:13:55+00:00

Pull driver core / debugfs update from Greg KH: "Here is the "big" driver core and debugfs update for 5.12-rc1 This set of driver core patches caused a bunch of problems in linux-next for the past few weeks, when Saravana tried to set fw_devlink=on as the default functionality. This caused a number of systems to stop booting, and lots of bugs were fixed in this area for almost all of the reported systems, but this option is not ready to be turned on just yet for the default operation based on this testing, so I've reverted that change at the very end so we don't have to worry about regressions in 5.12 We will try to turn this on for 5.13 if testing goes better over the next few months. Other than the fixes caused by the fw_devlink testing in here, there's not much more: - debugfs fixes for invalid input into debugfs_lookup() - kerneldoc cleanups - warn message if platform drivers return an error on their remove callback (a futile effort, but good to catch). All of these have been in linux-next for a while now, and the regressions have gone away with the revert of the fw_devlink change" * tag 'driver-core-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (35 commits) Revert "driver core: Set fw_devlink=on by default" of: property: fw_devlink: Ignore interrupts property for some configs debugfs: do not attempt to create a new file before the filesystem is initalized debugfs: be more robust at handling improper input in debugfs_lookup() driver core: auxiliary bus: Fix calling stage for auxiliary bus init of: irq: Fix the return value for of_irq_parse_one() stub of: irq: make a stub for of_irq_parse_one() clk: Mark fwnodes when their clock provider is added/removed PM: domains: Mark fwnodes when their powerdomain is added/removed irqdomain: Mark fwnodes when their irqdomain is added/removed driver core: fw_devlink: Handle suppliers that don't use driver core of: property: Add fw_devlink support for optional properties driver core: Add fw_devlink.strict kernel param of: property: Don't add links to absent suppliers driver core: fw_devlink: Detect supplier devices that will never be added driver core: platform: Emit a warning if a remove callback returned non-zero of: property: Fix fw_devlink handling of interrupts/interrupts-extended gpiolib: Don't probe gpio_device if it's not the primary device device.h: Remove bogus "the" in kerneldoc gpiolib: Bind gpio_device to a driver to enable fw_devlink=on by default ...

Merge tag 'dmaengine-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine

2021-02-23T23:05:10+00:00

Pull dmaengine updates from Vinod Koul: "We have couple of drivers removed a new driver and bunch of new device support and few updates to drivers for this round. New drivers/devices: - Intel LGM SoC DMA driver - Actions Semi S500 DMA controller - Renesas r8a779a0 dma controller - Ingenic JZ4760(B) dma controller - Intel KeemBay AxiDMA controller Removed: - Coh901318 dma driver - Zte zx dma driver - Sirfsoc dma driver Updates: - mmp_pdma, mmp_tdma gained module support - imx-sdma become modern and dropped platform data support - dw-axi driver gained slave and cyclic dma support" * tag 'dmaengine-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine: (58 commits) dmaengine: dw-axi-dmac: remove redundant null check on desc dmaengine: xilinx_dma: Alloc tx descriptors GFP_NOWAIT dmaengine: dw-axi-dmac: Virtually split the linked-list dmaengine: dw-axi-dmac: Set constraint to the Max segment size dmaengine: dw-axi-dmac: Add Intel KeemBay AxiDMA BYTE and HALFWORD registers dmaengine: dw-axi-dmac: Add Intel KeemBay AxiDMA handshake dmaengine: dw-axi-dmac: Add Intel KeemBay AxiDMA support dmaengine: drivers: Kconfig: add HAS_IOMEM dependency to DW_AXI_DMAC dmaengine: dw-axi-dmac: Add Intel KeemBay DMA register fields dt-binding: dma: dw-axi-dmac: Add support for Intel KeemBay AxiDMA dmaengine: dw-axi-dmac: Support burst residue granularity dmaengine: dw-axi-dmac: Support of_dma_controller_register() dmaegine: dw-axi-dmac: Support device_prep_dma_cyclic() dmaengine: dw-axi-dmac: Support device_prep_slave_sg dmaengine: dw-axi-dmac: Add device_config operation dmaengine: dw-axi-dmac: Add device_synchronize() callback dmaengine: dw-axi-dmac: move dma_pool_create() to alloc_chan_resources() dmaengine: dw-axi-dmac: simplify descriptor management dt-bindings: dma: Add YAML schemas for dw-axi-dmac dmaengine: ti: k3-psil: optimize struct psil_endpoint_config for size ...

Merge tag 'printk-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

2021-02-22T19:04:36+00:00

Pull printk updates from Petr Mladek: - New "no_hash_pointers" kernel parameter causes that %p shows raw pointer values instead of hashed ones. It is intended only for debugging purposes. Misuse is prevented by a fat warning message that is inspired by trace_printk(). - Prevent a possible deadlock when flushing printk_safe buffers during panic(). - Fix performance regression caused by the lockless printk ringbuffer. It was visible with huge log buffer and long messages. - Documentation fix-up. * tag 'printk-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: lib/vsprintf: no_hash_pointers prints all addresses as unhashed kselftest: add support for skipped tests lib: use KSTM_MODULE_GLOBALS macro in kselftest drivers printk: avoid prb_first_valid_seq() where possible printk: fix deadlock when kernel panic printk: rectify kernel-doc for prb_rec_init_wr()

Merge tag 'docs-5.12' of git://git.lwn.net/linux

2021-02-22T18:57:46+00:00

Pull documentation updates from Jonathan Corbet: "It has been a relatively quiet cycle in docsland. - As promised, the minimum Sphinx version to build the docs is now 1.7, and we have dropped support for Python 2 entirely. That allowed the removal of a bunch of compatibility code. - A set of treewide warning fixups from Mauro that I applied after it became clear nobody else was going to deal with them. - The automarkup mechanism can now create cross-references from relative paths to RST files. - More translations, typo fixes, and warning fixes" * tag 'docs-5.12' of git://git.lwn.net/linux: (75 commits) docs: kernel-hacking: be more civil docs: Remove the Microsoft rhetoric Documentation/admin-guide: kernel-parameters: Update nohlt section doc/admin-guide: fix spelling mistake: "perfomance" -> "performance" docs: Document cross-referencing using relative path docs: Enable usage of relative paths to docs on automarkup docs: thermal: fix spelling mistakes Documentation: admin-guide: Update kvm/xen config option docs: Make syscalls' helpers naming consistent coding-style.rst: Avoid comma statements Documentation: /proc/loadavg: add 3 more field descriptions Documentation/submitting-patches: Add blurb about backtraces in commit messages Docs: drop Python 2 support Move our minimum Sphinx version to 1.7 Documentation: input: define ABS_PRESSURE/ABS_MT_PRESSURE resolution as grams scripts/kernel-doc: add internal hyperlink to DOC: sections Update Documentation/admin-guide/sysctl/fs.rst docs: Update DTB format references docs: zh_CN: add iio index.rst translation docs/zh_CN: add iio ep93xx_adc.rst translation ...