Re: x86 ptep_get_and_clear question

[Jamie Lokier]

Manfred Spraul wrote:
> Ok, Is there one case were your pragmatic solutions is vastly faster?

> * mprotect: No. The difference is at most one additional locked
> instruction for each pte.

Oh, what instruction is that?

> * munmap(anon): No. We must handle delayed accessed anyway (don't call
> free_pages_ok() until flush_tlb_ipi returned). The difference is that we
> might have to perform a second pass to clear any spurious 0x40 bits.

That second pass is what I had in mind.

> * munmap(file): No. Second pass required for correct msync behaviour.

It is?

-- Jamie


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