Messages in this thread | | | Date | Wed, 14 Oct 2009 17:17:39 -0700 | From | Sukadev Bhattiprolu <> | Subject | Re: [RFC][v8][PATCH 0/10] Implement clone3() system call |
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H. Peter Anvin [hpa@zytor.com] wrote: | On 10/14/2009 03:36 PM, Sukadev Bhattiprolu wrote: | > H. Peter Anvin [hpa@zytor.com] 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.
so we allow 96 bits for flags ?
| 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.
So: struct clone_args { u64 flags_high; /* new clone flags (higher bits) */ u64 reserved1;
u32 nr_pids; u32 clone_args_size;
u64 child_stack_base; u64 child_stack_size;
u64 parent_tid_ptr; u64 child_tid_ptr; };
sys_clone3(u32 flags_low, struct clone_args *args, pid_t *pid_list)
BTW, on 64-bit architectures, the flags_low would be 64-bits, but the high- bits there would be ignored right ?
Not sure if we need a second reserved field now that we add ->clone_args_size.
Thanks,
Sukadev
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