Re: [PATCH v5 19/25] arm64/mm: Wire up PTE_CONT for user mappings

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



If so, I wonder if we could instead do that comparison modulo the access/dirty
bits,

I think that would work - but will need to think a bit more on it.

and leave ptep_get_lockless() only reading a single entry?

I think we will need to do something a bit less fragile. ptep_get() does collect
the access/dirty bits so its confusing if ptep_get_lockless() doesn't IMHO. So
we will likely want to rename the function and make its documentation explicit
that it does not return those bits.

ptep_get_lockless_noyoungdirty()? yuk... Any ideas?

Of course if I could convince you the current implementation is safe, I might be
able to sidestep this optimization until a later date?

As discussed (and pointed out abive), there might be quite some callsites where we don't really care about uptodate accessed/dirty bits -- where ptep_get() is used nowadays.

One way to approach that I had in mind was having an explicit interface:

ptep_get()
ptep_get_uptodate()
ptep_get_lockless()
ptep_get_lockless_uptodate()

Especially the last one might not be needed.

Futher, "uptodate" might not be the best choice because of PageUptodate() and friends. But it's better than "youngdirty"/"noyoungdirty" IMHO.

Of course, any such changes require care and are better done one step at at time separately.

--
Cheers,

David / dhildenb





[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux