Messages in this thread | | | Date | Fri, 23 Sep 2022 15:54:12 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v2] minmax: clamp more efficiently by avoiding extra comparison |
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On Fri, 23 Sep 2022 17:40:01 +0200 "Jason A. Donenfeld" <Jason@zx2c4.com> wrote:
> Currently the clamp algorithm does: > > if (val > hi) > val = hi; > if (val < lo) > val = lo; > > But since hi > lo by definition, this can be made more efficient with: > > if (val > hi) > val = hi; > else if (val < lo) > val = lo; > > So fix up the clamp and clamp_t functions to do this, adding the same > argument checking as for min and min_t. >
The patch adds 140 bytes of text to mm/memblock.o, for example. Presumably from the additional branch. Larger text means larger cache footprint means slower.
So where's the proof that this change gives us a more efficient kernel?
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