1431996bf9
Though tmpfs does not need it, percpu_counter_limited_add() can be twice as useful if it works sensibly with negative amounts (subs) - typically decrements towards a limit of 0 or nearby: as suggested by Dave Chinner. And in the course of that reworking, skip the percpu counter sum if it is already obvious that the limit would be passed: as suggested by Tim Chen. Extend the comment above __percpu_counter_limited_add(), defining the behaviour with positive and negative amounts, allowing negative limits, but not bothering about overflow beyond S64_MAX. Link: https://lkml.kernel.org/r/8f86083b-c452-95d4-365b-f16a2e4ebcd4@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Carlos Maiolino <cem@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Dave Chinner <dchinner@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Tim Chen <tim.c.chen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.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.