Namespaces exhausted CLONE_XXX bits problem
xemul at openvz.org
Mon Jan 14 05:45:08 PST 2008
I started looking at PTYs/TTYs/Console to make the appropriate
namespace and suddenly remembered that we have already
exhausted all the CLONE_ bits in 32-bit mask.
So, I recalled the discussions we had and saw the following
proposals of how to track this problem (with their disadvantages):
1. make the clone2 system call with 64-bit mask
- this is a new system call
2. re-use CLONE_STOPPED
- this will give us only one bit
3. merge existing bits into one
- we lose the ability to create them separately
4. implement a sys_unshare_ns system call with 64bit/arbitrary mask
- this is anew system call
- this will bring some dissymmetry between namespaces
5. use sys_indirect
- this one is not in even -mm tree yet and it's questionable
whether it will be at all
I have one more suggestion:
6. re-use bits, that don't make sense in sys_unshare (e.g.
CLONE_STOPPED, CLONE_PARENT_SETTID, CLONE_VFORK etc)
This will give us ~16 new bits, but this will look not very nice.
What do you think about all of this?
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