Messages in this thread | | | Subject | Re: [PATCH v1] clk: Convert managed get functions to devm_add_action API | From | Marc Gonzalez <> | Date | Mon, 2 Dec 2019 10:25:37 +0100 |
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On 02/12/2019 02:42, Dmitry Torokhov wrote:
> On Thu, Nov 28, 2019 at 10:56:30AM -0800, Bjorn Andersson wrote: > >> On Tue 26 Nov 08:13 PST 2019, Marc Gonzalez wrote: >> >>> Date: Tue, 26 Nov 2019 13:56:53 +0100 >>> >>> Using devm_add_action_or_reset() produces simpler code and smaller >>> object size: >>> >>> 1 file changed, 16 insertions(+), 46 deletions(-) >>> >>> text data bss dec hex filename >>> - 1797 80 0 1877 755 drivers/clk/clk-devres.o >>> + 1499 56 0 1555 613 drivers/clk/clk-devres.o >>> >>> Signed-off-by: Marc Gonzalez <marc.w.gonzalez@free.fr> >> >> Looks neat >> >> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> > > This however increases the runtime costs as each custom action cost us > an extra pointer. Given that in a system we likely have many clocks > managed by devres, I am not sure that this code savings is actually > gives us overall win. It might still, I just want to understand how we > are allocating/packing devres structures.
I'm not 100% sure what you are saying.
Are you arguing that the proposed patch increases the run-time cost of devm_clk_put() so much that the listed improvements (simpler source code, smaller object size) are not worth it?
AFAIU, the release action is only called - explicitly, when devm_clk_put() is called - implicitly, when the device is removed
How often are clocks removed?
In hot code-path (called hundreds of times per second) it makes sense to write more complex code, to shave a few cycles every iteration. But in cold code-path, I think it's better to write short/simple code.
Regards.
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