linux/Documentation/admin-guide/kernel-parameters.rst, branch v6.3

LoongArch: Make WriteCombine configurable for ioremap()

2023-04-18T11:38:58Z

LoongArch maintains cache coherency in hardware, but when paired with LS7A chipsets the WUC attribute (Weak-ordered UnCached, which is similar to WriteCombine) is out of the scope of cache coherency machanism for PCIe devices (this is a PCIe protocol violation, which may be fixed in newer chipsets). This means WUC can only used for write-only memory regions now, so this option is disabled by default, making WUC silently fallback to SUC for ioremap(). You can enable this option if the kernel is ensured to run on hardware without this bug. Kernel parameter writecombine=on/off can be used to override the Kconfig option. Cc: stable@vger.kernel.org Suggested-by: WANG Xuerui Reviewed-by: WANG Xuerui Signed-off-by: Huacai Chen

drivers/block: Remove PARIDE core and high-level protocols

2023-01-31T01:41:32Z

Remove PARIDE core and high level protocols, taking care not to break low-level drivers (used by pata_parport). Also update documentation. Signed-off-by: Ondrej Zary Acked-by: Jens Axboe Signed-off-by: Damien Le Moal

Docs/admin: alphabetize some kernel-parameters (part 1)

2022-04-16T08:49:05Z

Move some out-of-place kernel parameters into their correct locations. Move one out-of-order keyword/legend in kernel-parameters.rst. Add some missing keyword legends in kernel-parameters.rst: HIBERNATION HYPER_V and drop some obsolete/removed keyword legends: EIDE IOSCHED OSS TS XT Correct the location of the setup.h file. Signed-off-by: Randy Dunlap Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Cc: "Rafael J. Wysocki" Cc: Pavel Machek Signed-off-by: Jonathan Corbet

bitmap_parse: Support 'all' semantics

2021-05-10T22:38:20Z

RCU code supports an 'all' group as a special case when parsing rcu_nocbs parameter. This patch moves the 'all' support to the core bitmap_parse code, so that all bitmap users can enjoy this extension. Moving 'all' parsing to a bitmap_parse level also allows users to pass patterns together with 'all' in regular group:pattern format, for example, "rcu_nocbs=all:1/2" would offload all the even-numbered CPUs regardless of the number of CPUs on the system. Reviewed-by: Andy Shevchenko Signed-off-by: Yury Norov Signed-off-by: Paul E. McKenney

Merge tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-04-28T19:00:13Z

Pull RCU updates from Ingo Molnar: - Support for "N" as alias for last bit in bitmap parsing library (eg using syntax like "nohz_full=2-N") - kvfree_rcu updates - mm_dump_obj() updates. (One of these is to mm, but was suggested by Andrew Morton.) - RCU callback offloading update - Polling RCU grace-period interfaces - Realtime-related RCU updates - Tasks-RCU updates - Torture-test updates - Torture-test scripting updates - Miscellaneous fixes * tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits) rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu() rcu: Provide polling interfaces for Tiny RCU grace periods torture: Fix kvm.sh --datestamp regex check torture: Consolidate qemu-cmd duration editing into kvm-transform.sh torture: Print proper vmlinux path for kvm-again.sh runs torture: Make TORTURE_TRUST_MAKE available in kvm-again.sh environment torture: Make kvm-transform.sh update jitter commands torture: Add --duration argument to kvm-again.sh torture: Add kvm-again.sh to rerun a previous torture-test torture: Create a "batches" file for build reuse torture: De-capitalize TORTURE_SUITE torture: Make upper-case-only no-dot no-slash scenario names official torture: Rename SRCU-t and SRCU-u to avoid lowercase characters torture: Remove no-mpstat error message torture: Record kvm-test-1-run.sh and kvm-test-1-run-qemu.sh PIDs torture: Record jitter start/stop commands torture: Extract kvm-test-1-run-qemu.sh from kvm-test-1-run.sh torture: Record TORTURE_KCONFIG_GDB_ARG in qemu-cmd torture: Abstract jitter.sh start/stop into scripts rcu: Provide polling interfaces for Tree RCU grace periods ...

Documentation/admin-guide: kernel-parameters: correct the architectures for numa_balancing

2021-03-09T00:19:05Z

X86 isn't the only architecture supporting NUMA_BALANCING. ARM64, PPC, S390 and RISCV also support it: arch$ git grep NUMA_BALANCING arm64/Kconfig: select ARCH_SUPPORTS_NUMA_BALANCING arm64/configs/defconfig:CONFIG_NUMA_BALANCING=y arm64/include/asm/pgtable.h:#ifdef CONFIG_NUMA_BALANCING powerpc/configs/powernv_defconfig:CONFIG_NUMA_BALANCING=y powerpc/configs/ppc64_defconfig:CONFIG_NUMA_BALANCING=y powerpc/configs/pseries_defconfig:CONFIG_NUMA_BALANCING=y powerpc/include/asm/book3s/64/pgtable.h:#ifdef CONFIG_NUMA_BALANCING powerpc/include/asm/book3s/64/pgtable.h:#ifdef CONFIG_NUMA_BALANCING powerpc/include/asm/book3s/64/pgtable.h:#endif /* CONFIG_NUMA_BALANCING */ powerpc/include/asm/book3s/64/pgtable.h:#ifdef CONFIG_NUMA_BALANCING powerpc/include/asm/book3s/64/pgtable.h:#endif /* CONFIG_NUMA_BALANCING */ powerpc/include/asm/nohash/pgtable.h:#ifdef CONFIG_NUMA_BALANCING powerpc/include/asm/nohash/pgtable.h:#endif /* CONFIG_NUMA_BALANCING */ powerpc/platforms/Kconfig.cputype: select ARCH_SUPPORTS_NUMA_BALANCING riscv/Kconfig: select ARCH_SUPPORTS_NUMA_BALANCING riscv/include/asm/pgtable.h:#ifdef CONFIG_NUMA_BALANCING s390/Kconfig: select ARCH_SUPPORTS_NUMA_BALANCING s390/configs/debug_defconfig:CONFIG_NUMA_BALANCING=y s390/configs/defconfig:CONFIG_NUMA_BALANCING=y s390/include/asm/pgtable.h:#ifdef CONFIG_NUMA_BALANCING x86/Kconfig: select ARCH_SUPPORTS_NUMA_BALANCING if X86_64 x86/include/asm/pgtable.h:#ifdef CONFIG_NUMA_BALANCING x86/include/asm/pgtable.h:#endif /* CONFIG_NUMA_BALANCING */ On the other hand, setup_numabalancing() is implemented in mm/mempolicy.c which doesn't depend on architectures. Signed-off-by: Barry Song Reviewed-by: Palmer Dabbelt Acked-by: Palmer Dabbelt Cc: Mel Gorman Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: "Paul E. McKenney" Cc: Randy Dunlap Cc: Andrew Morton Cc: Thomas Gleixner Cc: Mauro Carvalho Chehab Cc: Viresh Kumar Cc: Mike Kravetz Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20210302084159.33688-1-song.bao.hua@hisilicon.com Signed-off-by: Jonathan Corbet

lib: bitmap: support "N" as an alias for size of bitmap

2021-03-08T22:16:58Z

While this is done for all bitmaps, the original use case in mind was for CPU masks and cpulist_parse() as described below. It seems that a common configuration is to use the 1st couple cores for housekeeping tasks. This tends to leave the remaining ones to form a pool of similarly configured cores to take on the real workload of interest to the user. So on machine A - with 32 cores, it could be 0-3 for "system" and then 4-31 being used in boot args like nohz_full=, or rcu_nocbs= as part of setting up the worker pool of CPUs. But then newer machine B is added, and it has 48 cores, and so while the 0-3 part remains unchanged, the pool setup cpu list becomes 4-47. Multiple deployment becomes easier when we can just simply replace 31 and 47 with "N" and let the system substitute in the actual number at boot; a number that it knows better than we do. Cc: Yury Norov Cc: Peter Zijlstra Cc: "Paul E. McKenney" Cc: Rasmus Villemoes Cc: Andy Shevchenko Suggested-by: Yury Norov # move it from CPU code Acked-by: Yury Norov Signed-off-by: Paul Gortmaker Signed-off-by: Paul E. McKenney

Documentation: kernel-parameters: add missing '<'

2021-01-28T22:24:06Z

Acked-by: Randy Dunlap Signed-off-by: Wolfram Sang Link: https://lore.kernel.org/r/20210127104343.5647-1-wsa+renesas@sang-engineering.com Signed-off-by: Jonathan Corbet

Documentation: admin: early_param()s are also listed in kernel-parameters

2020-12-31T22:46:18Z

Add info that "early_param()" kernel boot parameters are also listed in kernel-parameters.txt. Signed-off-by: Randy Dunlap Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org Link: https://lore.kernel.org/r/20201226174433.7885-1-rdunlap@infradead.org Signed-off-by: Jonathan Corbet

Documentation/admin-guide: mark memmap parameter is supported by a few architectures

2020-11-30T17:35:32Z

early_param memmap is only implemented on X86, MIPS and XTENSA. To avoid wasting users’ time on trying this on platform like ARM, mark it clearly. Signed-off-by: Barry Song Reviewed-by: Mike Rapoport Link: https://lore.kernel.org/r/20201128195121.2556-1-song.bao.hua@hisilicon.com Signed-off-by: Jonathan Corbet