On Tue, Dec 03, 2019 at 06:41:32AM -0700, Jonathan Corbet wrote: > On Tue, 3 Dec 2019 12:09:43 +0530 > Amol Grover <frextrite@xxxxxxxxx> wrote: > > > - Add more information about listRCU patterns taking examples > > from audit subsystem in the linux kernel. > > > > - The initially written audit examples are kept, even though they are > > slightly different in the kernel. > > > > - Modify inline text for better passage quality. > > > > - Fix typo in code-blocks and improve code comments. > > > > - Add text formatting (italics, bold and code) for better emphasis. > > Thanks for improving the documentation! I'll leave the RCU stuff to the > experts, but I do have one request... > > [...] > > > +When a process exits, ``release_task()`` calls ``list_del_rcu(&p->tasks)`` under > > +``tasklist_lock`` writer lock protection, to remove the task from the list of > > +all tasks. The ``tasklist_lock`` prevents concurrent list additions/removals > > +from corrupting the list. Readers using ``for_each_process()`` are not protected > > +with the ``tasklist_lock``. To prevent readers from noticing changes in the list > > +pointers, the ``task_struct`` object is freed only after one or more grace > > +periods elapse (with the help of ``call_rcu()``). This deferring of destruction > > +ensures that any readers traversing the list will see valid ``p->tasks.next`` > > +pointers and deletion/freeing can happen in parallel with traversal of the list. > > +This pattern is also called an **existence lock**, since RCU pins the object in > > +memory until all existing readers finish. > > Please don't put function names as literal text. If you just say > call_rcu(), it will be formatted correctly and cross-linked to the > appropriate kerneldoc entry. Saying ``call_rcu()`` defeats that and > clutters the plain-text reading experience. > Hi Jon, The cross-reference of the functions should be done automatically by sphinx while generating HTML, right? But when compiled none of the functions were cross-referenced hence "``" was added around the methods (and other symbols) to distinguish them from normal text. Thanks Amol > Thanks, > > jon
