1f827dab9e
- Optimise the RCU implementation to not allocate and free ck_epoch_records during runtime. Instead allocate two sets of ck_epoch_records per CPU for general purpose use. The first set is only used for reader locks and the second set is only used for synchronization and barriers and is protected with a regular mutex to prevent simultaneous issues. - Move the task structure away from the rcu_head structure and into the per-CPU structures. This allows the size of the rcu_head structure to be reduced down to the size of two pointers. - Fix a bug where the linux_rcu_barrier() function only waited for one per-CPU epoch record to be completed instead of all. - Use a critical section or a mutex to protect ck_epoch_begin() and ck_epoch_end() depending on RCU or SRCU type. All the ck_epoch_xxx() functions, except ck_epoch_register(), ck_epoch_unregister() and ck_epoch_recycle() are not re-entrant and needs a critical section or a mutex to operate in the LinuxKPI, after inspecting the CK implementation of the above mentioned functions. The simultaneous issues arise from per-CPU epoch records being shared between multiple threads depending on the amount of taskswitching and how many threads are involved with the RCU and SRCU operations. - Properly free all epoch records by using safe list traversal at LinuxKPI module unload. It turns out the ck_epoch_recycle() always have the records on an internal list and use a flag in the epoch record to track allocated and free entries. This would lead to use after free during module unload. - Remove redundant synchronize_rcu() call from the linux_compat_uninit() function. Let the linux_rcu_runtime_uninit() function do the final rcu_barrier() instead. MFC after: 1 week Sponsored by: Mellanox Technologies
FreeBSD Source:
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.
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