3042f83f19
Update the kvfree_call_rcu() function with head-less support. This allows RCU to reclaim objects without an embedded rcu_head. tree-RCU: We introduce two chains of arrays to store SLAB-backed and vmalloc pointers, each. Storage in either of these arrays does not require embedding an rcu_head within the object. Maintaining the arrays may become impossible due to high memory pressure. For such cases there is an emergency path. Objects with rcu_head inside are just queued on a backup rcu_head list. Later on that list is drained. As for the head-less variant, as the current context can sleep, the following emergency measures are applied: a) Synchronously wait until a grace period has elapsed. b) Call kvfree(). tiny-RCU: For double argument calls, there are no new changes in behavior. For single argument call, kvfree() is directly inlined on the current stack after a synchronize_rcu() call. Note that for tiny-RCU, any call to synchronize_rcu() is actually a quiescent state, therefore it does nothing. Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> Co-developed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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.
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.