freebsd kernel with SKQ
5b603201cc
without Giant held. A quick outline of the locking strategy: Since all IOMMUs are synchronized, there is a single lock, iommu_mtx, which protects the hardware registers (where needed) and the global and per-IOMMU software states. As soon as the IOMMUs are divorced, each struct iommu_state will have its own mutex (and the remaining global state will be moved into the struct). The dvma rman has its own internal mutex; the TSB slots may only be accessed by the owner of the corresponding resource, so neither needs extra protection. Since there is a second access path to maps via LRU queues, the consumer- provided locking is not sufficient; therefore, each map which is on a queue is additionally protected by iommu_mtx (in part, there is one member which only the map owner may access). Each map on a queue may be accessed and removed from or repositioned in a queue in any context as long as the lock is held; only the owner may insert a map. To reduce lock contention, some bus_dma functions remove the map from the queue temporarily (on behalf of the map owner) for some operations and reinsert it when they are done. Shorter operations and operations which are not done on behalf of the lock owner are completely covered by the lock. To facilitate the locking, reorganize the streaming buffer handling; while being there, fix an old oversight which would cause the streaming buffer to always be flushed, regardless of whether streaming was enabled in the TSB entry. The streaming buffer is still disabled for now, since there are a number of drivers which lack critical bus_dmamp_sync() calls. Additional testing by: jake |
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| bin | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| 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 ``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. 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. 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