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author | Hugh Dickins <hughd@google.com> | 2023-10-12 07:40:09 +0300 |
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committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-19 00:34:14 +0300 |
commit | 1431996bf9088ee59f8017637ab9a7f89909ae63 (patch) | |
tree | 8b0533590f06ee436b37353695b35730eb7aa976 /mm/gup_test.c | |
parent | beb9868628445306958fd7b2da1cd369a4a381cc (diff) | |
download | linux-1431996bf9088ee59f8017637ab9a7f89909ae63.tar.xz |
percpu_counter: extend _limited_add() to negative amounts
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>
Diffstat (limited to 'mm/gup_test.c')
0 files changed, 0 insertions, 0 deletions