Messages in this thread | | | Date | Wed, 23 Aug 2023 07:25:52 -0700 | From | Jakub Kicinski <> | Subject | Re: [PATCH net-next v7 1/6] page_pool: frag API support for 32-bit arch with 64-bit DMA |
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On Wed, 23 Aug 2023 11:03:31 +0800 Yunsheng Lin wrote: > On 2023/8/22 23:38, Jakub Kicinski wrote: > > On Tue, 22 Aug 2023 17:21:35 +0800 Yunsheng Lin wrote: > >> As the CONFIG_PHYS_ADDR_T_64BIT seems to used widely in x86/arm/mips/powerpc, > >> I am not sure if we can really make the above assumption. > >> > >> https://elixir.free-electrons.com/linux/v6.4-rc6/K/ident/CONFIG_PHYS_ADDR_T_64BIT > > > > Huh, it's actually used a lot less than I anticipated! > > > > None of the x86/arm/mips/powerpc systems matter IMHO - the only _real_ > > Is there any particular reason that you think that the above systems does > not really matter?
Not the systems themselves but the combination of a 32b arch with an address space >16TB. All those arches have 64b equivalent, seems logical to use the 64b version for a system with a large address space. If we're talking about a system which ends up running Linux.
> As we have made a similar wrong assumption about those arches before, I am > really trying to be more cautious about it. > > I searched through the web, some seems to be claiming that "32-bits is DEAD", > I am not sure if there is some common agreement among the kernel community, > is there any previous discussion about that?
My suspicion/claim is that 32 + PAGE_SHIFT should be enough bits for any 32b platform.
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