Messages in this thread | | | Date | Tue, 12 Apr 2022 16:30:58 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH V5 3/7] x86/entry: Move PUSH_AND_CLEAR_REGS out of error_entry() |
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On Tue, Apr 12, 2022 at 09:52:44PM +0800, Lai Jiangshan wrote: > The mapped size for the text is always 2M when the kernel is booted > since it is 2M-aligned. So I don't think the size is a concern.
This is not how this argumentation works: you add 0.01% size increase here, 0.01% slowdown there and it all soon adds up into a bloated kernel. Besides, nowadays the kernel runs a lot as a guest and guest kernel size does matter.
So no, just because you want to turn error_entry() into C code and for that you'll add some bloat doesn't justify it in my book. All changes to core code need to be absolutely needed and justifiable.
> For example, a heavy page fault and IPI or timer at the same time. > I'm not sure if it is a real case.
I wouldn't be surprised if it shows in some perf profiles.
> I'm Okay with asm_error_entry(). And also we can use an ASM function > containing PUSH_AND_CLEAR_REGS only.
Just do the necessary and minimal thing - this is core code and in asm for that matter, so be conservative pls. This is not some random driver.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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