sched/fair: Add lsub_positive() and use it consistently

The following pattern:

   var -= min_t(typeof(var), var, val);

is used multiple times in fair.c.

The existing sub_positive() already captures that pattern, but it also
adds an explicit load-store to properly support lockless observations.
In other cases the pattern above is used to update local, and/or not
concurrently accessed, variables.

Let's add a simpler version of sub_positive(), targeted at local variables
updates, which gives the same readability benefits at calling sites,
without enforcing {READ,WRITE}_ONCE() barriers.

Signed-off-by: Patrick Bellasi <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Dietmar Eggemann <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Morten Rasmussen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Quentin Perret <[email protected]>
Cc: Steve Muckle <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Todd Kjos <[email protected]>
Cc: Vincent Guittot <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions