Messages in this thread | | | Date | Mon, 13 Feb 2006 21:20:46 +0200 | From | "Michael S. Tsirkin" <> | Subject | Re: madvise MADV_DONTFORK/MADV_DOFORK |
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Quoting Linus Torvalds <torvalds@osdl.org>: > > > > Add madvise options to control whether memory range is inherited across fork. > > Useful e.g. for when hardware is doing DMA from/into these pages. > > > > Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il> > > > > - if (mpnt->vm_flags & VM_DONTCOPY) { > > + if (mpnt->vm_flags & (VM_DONTCOPY | VM_DONTFORK)) { > > Why? > > That VM_DONTCOPY _is_ DONTFORK. > > Don't add a new useless DONTFORK that doesn't have any value.
When this was last discussed, Hugh Dickins said: > If a driver sets VM_DONTCOPY, it's likely to be because the driver knows it'll > cause some nastiness (memory corruption, memory leak, lockup...) if it were > copied. The memory belongs to the driver, it's letting the process have a > window on it. I don't think we should now let the process overrule it.
Here's a pointer to the relevant discussion: http://lkml.org/lkml/2005/11/3/112
-- Michael S. Tsirkin Staff Engineer, Mellanox Technologies - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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