powerpc/mm/slice: implement slice_check_range_fits

Browse source

Rather than build slice masks from a range then use that to check for
fit in a candidate mask, implement slice_check_range_fits that checks
if a range fits in a mask directly.

This allows several structures to be removed from stacks, and also we
don't expect a huge range in a lot of these cases, so building and
comparing a full mask is going to be more expensive than testing just
one or two bits of the range.

On POWER8, this increases vfork+exec+exit performance by 0.3%
and reduces time to mmap+munmap a 64kB page by 5%.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

...

This commit is contained in:

Nicholas Piggin 2018-03-07 11:37:13 +10:00 • committed by Michael Ellerman

parent 5709f7cfd8

commit ae3066bd1c

1 changed files with 34 additions and 28 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

62

arch/powerpc/mm/slice.c

View file