Linux mainline fork with MSM8998 patches | https://mainline.space | Currently supported devices:
OnePlus 5/5T, Xiaomi Mi 6, F(x)tec Pro¹ (2019 QX1000 model) & Sony Xperia XZ Premium (UNTESTED!)
b4c6f86ec2
The irq_work callback is invoked in hard IRQ context. By default all callbacks are scheduled for invocation right away (given supported by the architecture) except for the ones marked IRQ_WORK_LAZY which are delayed until the next timer-tick. While looking over the callbacks, some of them may acquire locks (spinlock_t, rwlock_t) which are transformed into sleeping locks on PREEMPT_RT and must not be acquired in hard IRQ context. Changing the locks into locks which could be acquired in this context will lead to other problems such as increased latencies if everything in the chain has IRQ-off locks. This will not solve all the issues as one callback has been noticed which invoked kref_put() and its callback invokes kfree() and this can not be invoked in hardirq context. Some callbacks are required to be invoked in hardirq context even on PREEMPT_RT to work properly. This includes for instance the NO_HZ callback which needs to be able to observe the idle context. The callbacks which require to be run in hardirq have already been marked. Use this information to split the callbacks onto the two lists on PREEMPT_RT: - lazy_list Work items which are not marked with IRQ_WORK_HARD_IRQ will be added to this list. Callbacks on this list will be invoked from a per-CPU thread. The handler here may acquire sleeping locks such as spinlock_t and invoke kfree(). - raised_list Work items which are marked with IRQ_WORK_HARD_IRQ will be added to this list. They will be invoked in hardirq context and must not acquire any sleeping locks. The wake up of the per-CPU thread occurs from irq_work handler/ hardirq context. The thread runs with lowest RT priority to ensure it runs before any SCHED_OTHER tasks do. [bigeasy: melt tglx's irq_work_tick_soft() which splits irq_work_tick() into a hard and soft variant. Collected fixes over time from Steven Rostedt and Mike Galbraith. Move to per-CPU threads instead of softirq as suggested by PeterZ.] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211007092646.uhshe3ut2wkrcfzv@linutronix.de |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.