98087a066f
paging. Shadow objects are marked with a COLLAPSING flag while they are collapsing with their backing object. This gives us an explicit test rather than overloading paging-in-progress. While split is on-going we mark an object with SPLIT. These two operations will modify the swap tree so they must be serialized and swap_pager_getpages() can now directly detect these conditions and page more conservatively. Callers to vm_object_collapse() now will reliably wait for a collapse to finish so that the backing chain is as short as possible before other decisions are made that may inflate the object chain. For example, split, coalesce, etc. It is now safe to run fault concurrently with collapse. It is safe to increase or decrease paging in progress with no lock so long as there is another valid ref on increase. This change makes collapse more reliable as a secondary benefit. The primary benefit is making it safe to drop the object lock much earlier in fault or never acquire it at all. This was tested with a new shadow chain test script that uncovered long standing bugs and will be integrated with stress2. Reviewed by: kib, markj Differential Revision: https://reviews.freebsd.org/D22908
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
FreeBSD
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
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), config(8), https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information, including setting make(1) variables.
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.
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.
stand Boot loader sources.
sys Kernel sources.
sys/<arch>/conf Kernel configuration files. GENERIC is the configuration
used in release builds. NOTES contains documentation of
all possible entries.
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:
https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/current-stable.html