Re: [PATCH v4 01/15] docs/mm: add document for swap table

[Barry Song]

> Perhaps you could describe the swap table as similar to a PTE page table
> representing the swap cache mapping.
> That is correct for most 32-bit and 64-bit systems,
> but not for every machine.
>
> The only exception is a 32-bit system with a 64-bit physical address
> (Large Physical Address Extension, LPAE), which uses a 4 KB PTE table
> but a 2 KB swap table because the pointer is 32 bit while each page
> table entry is 64 bit.
>
> Maybe we can simply say that the number of entries in the swap table
> is the same as in a PTE page table?

BTW, as Kairui mentioned, you plan to store the PFN instead of a
pointer in phase 2.

I wonder whether we need to switch to atomic64_t on systems where the
physical address is 64 bit but the virtual address is 32 bit :-)

Thanks
Barry