Messages in this thread | | | Date | Tue, 10 Jul 2007 15:55:30 -0500 | From | William Tambe <> | Subject | Re: Concerning a post that you made about expandable anonymous shared mappings |
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Hugh Dickins wrote: > On Mon, 9 Jul 2007, William Tambe wrote: >> Hugh Dickins wrote: >>> I've come right around to your original view, Stas, and William's: >>> if that mmap creates such an object, then the expanding mremap really >>> ought to be useful, and allow the underlying object to be expanded. >>> The shared anonymous object is already anomalous: expanding it on >>> fault makes it more consistent with its own nature, not less. >>> ... >>> Here's a patch against 2.6.22-rc7: would you, Stas, put your >>> Signed-off-by into this, and accept authorship - although I'm >>> sending this back to you, it's very much your idea, and only >>> trivially modified from your three-year-old patch by me. If >>> you're agreeable, I can then forward it or its shmem_zero_fault >>> equivalent to Andrew when we see which way 2.6.23 is going. >> ... >> Will this patch be added to stable versions of the linux kernel? >> Please let me know. > > I confess that the lukewarm response from Stas cooled my enthusiasm, > and left me feeling that perhaps I'm an idiot to be adding such a > feature so many years too late; and my old caution about the way > a child could use up memory not freed on child's exit, unknown to > parent, returned to haunt me. That could be documented for new > usages, but I just don't know what usages are already out there, > and fear I'd be introducing an exploit. > > It most certainly will not be added to a stable version of the > linux kernel, if by that you mean 2.6.22.N or 2.6.21.N etc. > Though it can be viewed as a bugfix, the patch as it stands > seems in danger of introducing its own bug, and it's just too > much of a feature to be suitable for a -stable release. > > But more probably you meant, will it be in 2.6.23 or 2.6.24? > Sorry to be such a vacillatiing wimp, but I don't know. > How well are you managing with the shm_open approach? > > Hugh >
I understand your concern. But since I am working on a dynamic memory management code that I wish to use with other projects that I have, I didn't find appropriate to use shm_open.
In fact there is a name associated with the shared memory requested with shm_open, so that it can be mmap(ed) in another process. And I do not wish to have it accessible by any other process, unless I choose to do so.
shm_open is great, but it doesn't quite fit my needs. And I think remap(ing) ANONYMOUS memory kind of make a lot of things easier.
Can that feature be added at least to release candidates series so that everybody can try it and see how well it does?
Sincerely, William Tambe - 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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