freebsd kernel with SKQ
58f61ce4eb
The dealock was caused in the following way: - thread T1 on CPU C1 holds a spin mutex, IPIs CPU C2 and waits for the IPI to be handled - C2 executes timer interrupt filter, thus has interrupts disabled, and gets blocked on the spin mutex held by T1 The problem seems to have been introduced by simplifications made to OpenSolaris code during porting. The problem is fixed by reorganizing the code to more closely resemble the upstream version. Interrupt filter (cyclic_fire) now doesn't acquire any locks, all per-CPU data accesses are performed on a target CPU with preemption and interrupts disabled thus precluding concurrent access to the data. cyp_mtx spin mutex is used to disable preemtion and interrupts; it's not used for classical mutual exclusion, because xcall already serializes calls to a CPU. It's an emulation of OpenSolaris cyb_set_level(CY_HIGH_LEVEL) call, the spin mutexes could probably be reduced to just a spinlock_enter()/_exit() pair. Diff with upstream version is now reduced by ~500 lines, however it still remains quite large - many things that are not needed (at the moment) or are irrelevant on FreeBSD were simply ripped out during porting. Examples of such things: - support for CPU onlining/offlining - support for suspend/resume - support for running callouts at soft interrupt levels - support for callout rebinding from CPU to CPU - support for CPU partitions Tested by: Artem Belevich <fbsdlist@src.cx> MFC after: 3 weeks X-MFC with: r216252 |
||
|---|---|---|
| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.mips | ||
| ObsoleteFiles.inc | ||
| README | ||
| UPDATING | ||
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``world'' target should only be used in cases where the source tree has not changed from the currently running version. See: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html for more information, including setting make(1) variables. The ``buildkernel'' and ``installkernel'' targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html And in the config(8) man page. Note: If you want to build and install the kernel with the ``buildkernel'' and ``installkernel'' targets, you might need to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/<arch>/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/user commands. cddl Various commands and libraries under the Common Development and Distribution License. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberos5 Kerberos5 (Heimdal) package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. rescue Build system for statically linked /rescue utilities. sbin System commands. secure Cryptographic libraries and commands. share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html