freebsd with flexible iflib nic queues
2cd5358a66
close or assert the bug that it is clear when leaving. Remove an unrelated rotted comment that was attached to the buggy clearing. Since draining is not done in more cases, flushing is needed in more cases, so start fixing flushing: - do a full flush in ttydisc_close(). State what POSIX requires more clearly. This was missing ttydevsw_pktnotify() calls to tell the devsw layer to flush. Hardware tty drivers don't actually flush since they don't understand this API. - fix 2 missing wakeups in tty_flush(). Most of the wakeups here are unnecessary for last close. But ttydisc_close() did one of the missing ones. This flow control bug ameliorated the design bug of requiring potentially unbounded waits in draining. Software flow control is the easiest way to get an unbounded wait, and a long wait is sometimes actually useful. Users can type the xoff character on the receiver and (if ixon is set on the sender) expect the output to be held until the user is ready for more. Hardware flow control can also give the unbounded wait, and this bug didn't affect hardware flow control. Unbounded waits from hardware flow control take a more unusual configuration. E.g., a terminal program that controls the modem status lines, or unplugging the cable in a configuration where this doesn't break the connection. The design bug is still ameliorated by a newer bug in draining for last close -- the 1 second timeout. E.g., if the user types the xoff character and the sender reaches last close, then output is not resumed and the wait times out after just 1 second. This is broken, but preferable to an unbounded wait. Before this change, the output was resumed immediately and usually completed. Submitted by: bde MFC after: 2 weeks |
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| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| 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. See build(7) and 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. See build(7), config(8), and http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information. 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 kernel configuration files reside in the sys/<arch>/conf sub-directory. GENERIC is the default configuration used in release builds. NOTES contains entries and documentation for all possible devices, not just those commonly used. 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. tests Regression tests which can be run by Kyua. See tests/README for additional information. 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