freebsd with flexible iflib nic queues
85f190e4d1
Problem: selwakeup required calling pfind which would cause lock order reversals with the allproc_lock and the per-process filedesc lock. Solution: Instead of recording the pid of the select()'ing process into the selinfo structure, actually record a pointer to the thread. To avoid dereferencing a bad address all the selinfo structures that are in use by a thread are kept in a list hung off the thread (protected by sellock). When a selwakeup occurs the selinfo is removed from that threads list, it is also removed on the way out of select or poll where the thread will traverse its list removing all the selinfos from its own list. Problem: Previously the PROC_LOCK was used to provide the mutual exclusion needed to ensure proper locking, this couldn't work because there was a single condvar used for select and poll and condvars can only be used with a single mutex. Solution: Introduce a global mutex 'sellock' which is used to provide mutual exclusion when recording events to wait on as well as performing notification when an event occurs. Interesting note: schedlock is required to manipulate the per-thread TDF_SELECT flag, however if given its own field it would not need schedlock, also because TDF_SELECT is only manipulated under sellock one doesn't actually use schedlock for syncronization, only to protect against corruption. Proc locks are no longer used in select/poll. Portions contributed by: davidc |
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| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| kerberosIV | ||
| lib | ||
| libexec | ||
| release | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| COPYRIGHT | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.upgrade | ||
| 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/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 have to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/i386/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. kerberosIV Kerberos 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/handbook/synching.html