Re: [RFC][v8][PATCH 0/10] Implement clone3() system call

From: H. Peter Anvin
Date: Wed Oct 14 2009 - 19:04:05 EST


On 10/14/2009 03:36 PM, Sukadev Bhattiprolu wrote:
> H. Peter Anvin [hpa@xxxxxxxxx] wrote:
> |
> | Overall it seems sane to:
> |
> | a) make it an actual 3-argument call;
> | b) make the existing flags a u32 forever, and make it a separate
> | argument;
> | c) any new expansion can be via the struct, which may want to have
> | an "c3_flags" field first in the structure.
>
> Ok, So will this work ?
>
> struct clone_args {
> u32 flags_high; /* new clone flags (higher bits) */
> u32 reserved1;
> u32 nr_pids;
> u32 reserved2;
> u64 child_stack_base;
> u64 child_stack_size;
> u64 parent_tid_ptr;
> u64 child_tid_ptr;
> u64 reserved3;
> };
>
> sys_clone3(u32 flags_low, struct clone_args *args, pid_t *pid_list)
>
> Even on 64bit architectures the applications have to use sys_clone3() for
> the extended features.

Yes, although I'd just make flags_high a u64. The other thing that
might be worthwhile is to have a length field on the structure; that way
we could add new fields at the end if ever necessary in the future.

-hpa
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