Messages in this thread | | | Subject | Re: [openib-general] Re: madvise MADV_DONTFORK/MADV_DOFORK | From | Roland Dreier <> | Date | Mon, 13 Feb 2006 11:16:32 -0800 |
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Linus> Why?
Linus> That VM_DONTCOPY _is_ DONTFORK.
Linus> Don't add a new useless DONTFORK that doesn't have any Linus> value.
VM_DONTCOPY is hardly used in the kernel, so the semantics aren't very precisely defined. But the idea is that a driver setting VM_DONTCOPY probably has a good reason for doing it, and we don't want userspace to be able to erase that flag through madvise().
As Hugh said in his suggestion for a better changelog entry:
> Explain that MADV_DONTFORK should be reversible, hence > MADV_DOFORK; but should not be reversible on areas a driver has > so marked, hence VM_DONTFORK distinct from VM_DONTCOPY.
Perhaps we don't care for now, and we should wait and add VM_KERNEL_DONTCOPY later if we really need it. I honestly don't know.
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