fb31340f8a
Currently, rcu_gp_cleanup() scans the rcu_node tree in order to reset state to reflect the end of the grace period. It also checks to see whether a new grace period is needed, but in a number of cases, rather than directly cause the new grace period to be immediately started, it instead leaves the grace-period-needed state where various fail-safes can find it. This works fine, but results in higher contention on the root rcu_node structure's ->lock, which is undesirable, and contention on that lock has recently become noticeable. This commit therefore makes rcu_gp_cleanup() immediately start a new grace period if there is any need for one. It is quite possible that it will later be necessary to throttle the grace-period rate, but that can be dealt with when and if. Reported-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Nicholas Piggin <npiggin@gmail.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.