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OPNsense - FreeBSD source
b3fed13e9d
In order to avoid livelock, swapoff() skips over objects with a nonzero pip count and makes another pass if necessary. Since it is impossible to know which objects we care about, it would choose an arbitrary object with a nonzero pip count and wait for it before making another pass, the theory being that this object would finish paging about as quickly as the ones we care about. Unfortunately, we may have slept since we acquired a reference to this object. Hack around this problem by tsleep()ing on the pointer anyway, but timeout after a fixed interval. More elegant solutions are possible, but the ones I considered unnecessarily complicate this rare case. Also, kill some nits that seem to have crept into the swapoff() code in the last 75 revisions or so: - Don't pass both sp and sp->sw_used to swap_pager_swapoff(), since the latter can be derived from the former. - Replace swp_pager_find_dev() with something simpler. There's no need to iterate over the entire list of swap devices just to determine if a given block is assigned to the one we're interested in. - Expand the scope of the swhash_mtx in a couple of places so that it isn't released and reacquired once for every hash bucket. - Don't drop the swhash_mtx while holding a reference to an object. We need to lock the object first. Unfortunately, doing so would violate the established lock order, so use VM_OBJECT_TRYLOCK() and try again on a subsequent pass if the object is already locked. - Refactor swp_pager_force_pagein() and swap_pager_swapoff() a bit. |
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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 | ||
| installworld_newk | ||
| installworld_oldk | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| README | ||
| UPDATING | ||
| UPDATING.64BTT | ||
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