e7d38f16c2
Pull RCU updates from Paul McKenney: - Documentation updates, perhaps most notably Neil Brown's writeup of the reference-counting analogy to RCU. - Expedited grace-period cleanups. - Remove CONFIG_RCU_FAST_NO_HZ due to lack of valid users. I have asked around, posted a blog entry, and sent this series to LKML without result. - Miscellaneous fixes. - RCU callback offloading updates, perhaps most notably Frederic Weisbecker's updates allowing CPUs booted in the de-offloaded state to be offloaded at runtime. - nolibc fixes from Willy Tarreau and Anmar Faizi, but also including Mark Brown's addition of gettid(). - RCU Tasks Trace fixes, including changes that increase the scalability of call_rcu_tasks_trace() for the BPF folks (Martin Lau and KP Singh). - Various fixes including those from Wander Lairson Costa and Li Zhijian. - Fixes plus addition of tests for the increased call_rcu_tasks_trace() scalability. * tag 'rcu.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (87 commits) rcu/nocb: Merge rcu_spawn_cpu_nocb_kthread() and rcu_spawn_one_nocb_kthread() rcu/nocb: Allow empty "rcu_nocbs" kernel parameter rcu/nocb: Create kthreads on all CPUs if "rcu_nocbs=" or "nohz_full=" are passed rcu/nocb: Optimize kthreads and rdp initialization rcu/nocb: Prepare nocb_cb_wait() to start with a non-offloaded rdp rcu/nocb: Remove rcu_node structure from nocb list when de-offloaded rcu-tasks: Use fewer callbacks queues if callback flood ends rcu-tasks: Use separate ->percpu_dequeue_lim for callback dequeueing rcu-tasks: Use more callback queues if contention encountered rcu-tasks: Avoid raw-spinlocked wakeups from call_rcu_tasks_generic() rcu-tasks: Count trylocks to estimate call_rcu_tasks() contention rcu-tasks: Add rcupdate.rcu_task_enqueue_lim to set initial queueing rcu-tasks: Make rcu_barrier_tasks*() handle multiple callback queues rcu-tasks: Use workqueues for multiple rcu_tasks_invoke_cbs() invocations rcu-tasks: Abstract invocations of callbacks rcu-tasks: Abstract checking of callback lists rcu-tasks: Add a ->percpu_enqueue_lim to the rcu_tasks structure rcu-tasks: Inspect stalled task's trc state in locked state rcu-tasks: Use spin_lock_rcu_node() and friends rcutorture: Combine n_max_cbs from all kthreads in a callback flood ...
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.