Messages in this thread | | | From | Linus Torvalds <> | Date | Fri, 8 Oct 2021 13:25:51 -0700 | Subject | Re: [GIT PULL] arm64 fixes for 5.15-rc5 |
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On Fri, Oct 8, 2021 at 11:37 AM Catalin Marinas <catalin.marinas@arm.com> wrote: > > Pingfan Liu (2): > kernel/irq: make irq_{enter,exit}() in handle_domain_irq() arch optional > arm64: entry: avoid double-accounting IRQ RCU entry
Ugh. This is *really* ugly. And it seems to be going exactly the wrong way.
I read the commit descriptions, and it still doesn't answer the fundamental question of why arm64 needs to do the accounting in arch-specific code, and disable the generic code.
It says
To fix this, we must perform all the accounting from the architecture code. We prevent the IRQ domain code from performing any accounting by selecting HAVE_ARCH_IRQENTRY, and must call irq_enter_rcu() and irq_exit_rcu() around invoking the root IRQ handler.
but at no point does it actually explain *why* all the accounting needs to be done by the architecture code.
Yes, yes, I read the previous paragraph. But why isn't the fix to just stop doing the double accounting in the arm64 specific code?
Instead it doubles down on that "let's do this non-arch-specific accounting in arch-specific code", making the common code uglier and weaker.
I initially pulled this, and then I just unpulled in disgust.
Please explain why arm64 does this bad thing, and why the fix isn't "fix arm64", but instead "make the generic code uglier and harder to maintain and follow".
Really, from all the explanations those commits give, the natural thing to do would be "just fix arm64".
So if that really isn't the answer, then the explanations are clearly lacking.
Linus
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