Messages in this thread | | | Date | Wed, 6 Jun 2007 16:29:13 -0700 (PDT) | From | Davide Libenzi <> | Subject | Re: [patch 7/8] fdmap v2 - implement sys_socket2 |
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On Thu, 7 Jun 2007, Alan Cox wrote:
> > > prctl(PR_SPARSEFD, 1); > > > > > > to turn on sparse fd allocation for a process ? > > > > There was a little discussion where I tried to whisper something similar, > > but Linus and Uli shot me :) - with good reasons IMO. > > You may link to runtimes that are not non-sequentialfd aware, and will > > break them. > > Linking to the correct version of a libary and getting the library > versioning right is not rocket science and isn't a sane excuse. Its no > different to the stdio to large fd migration issues with many Unixen and > they all coped just fine.
I don't think it's a matter of versioning. Many userspace libraries expects their fds to be compact (for many reasons - they use select, they use them to index 0-based arrays, etc...), and if the kernel suddendly starts returning values in the 1<<28 up arena, they sure won't be happy. So I believe that the correct way is that the caller specifically selects the feature, leaving the legacy fd allocation as default.
- Davide
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