On (22/10/18 13:50), Andrew Morton wrote: > Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in > update_used_max. x86 CMPXCHG instruction returns success in ZF flag, so > this change saves a compare after cmpxchg (and related move instruction in > front of cmpxchg). > > Also, reorder code a bit to remove additional compare and conditional jump > from the assembly code. Together, hese two changes save 15 bytes from the > function when compiled for x86_64. > > No functional change intended. > > Link: https://lkml.kernel.org/r/20221018145154.3699-1-ubizjak@xxxxxxxxx > Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx> > Cc: Minchan Kim <minchan@xxxxxxxxxx> > Cc: Nitin Gupta <ngupta@xxxxxxxxxx> > Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> I totally missed that patch. Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
