Pulled for ckpt-v22-dev (will push soon).
Oren.
On 05/05/2010 11:22 PM, Sukadev Bhattiprolu wrote:
> The typos/errors were identified by Randy Dunlap. Also add a pointer to the
> user-cr git tree and a note about building eclone() library interface for other
> architectures. This pointer can probably be removed when eclone() makes it
> into libc.
>
> Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
> ---
> Documentation/eclone | 37 ++++++++++++++++++++++---------------
> 1 files changed, 22 insertions(+), 15 deletions(-)
>
> diff --git a/Documentation/eclone b/Documentation/eclone
> index c2f1b4b..c1032d5 100644
> --- a/Documentation/eclone
> +++ b/Documentation/eclone
> @@ -13,7 +13,7 @@ struct clone_args {
> sys_eclone(u32 flags_low, struct clone_args * __user cargs, int cargs_size,
> pid_t * __user pids)
>
> - In addition to doing everything that clone() system call does, the
> + In addition to doing everything that the clone() system call does, the
> eclone() system call:
>
> - allows additional clone flags (31 of 32 bits in the flags
> @@ -30,7 +30,7 @@ sys_eclone(u32 flags_low, struct clone_args * __user cargs, int cargs_size,
> pids to specify during restart.
>
> The @flags_low parameter is identical to the 'clone_flags' parameter
> - in existing clone() system call.
> + in the existing clone() system call.
>
> The fields in 'struct clone_args' are meant to be used as follows:
>
> @@ -47,35 +47,34 @@ sys_eclone(u32 flags_low, struct clone_args * __user cargs, int cargs_size,
> clone() and clone2() (on IA64) system calls. The usage of
> these two fields depends on the processor architecture.
>
> - Most architectures use ->child_stack to pass-in a stack-pointer
> + Most architectures use ->child_stack to pass in a stack-pointer
> itself and don't need the ->child_stack_size field. On these
> architectures the ->child_stack_size field must be 0.
>
> - Some architectures, eg IA64, use ->child_stack to pass-in the
> + Some architectures, e.g. IA64, use ->child_stack to pass in the
> base of the region allocated for stack. These architectures
> - must pass in the size of the stack-region in ->child_stack_size.
> + must pass in the size of the stack region in ->child_stack_size.
>
> u64 parent_tid_ptr;
> u64 child_tid_ptr;
>
> These two fields correspond to the 'parent_tid_ptr' and
> - 'child_tid_ptr' fields in the clone() system call
> + 'child_tid_ptr' fields in the clone() system call.
>
> u32 nr_pids;
>
> nr_pids specifies the number of pids in the @pids array
> parameter to eclone() (see below). nr_pids should not exceed
> - the current nesting level of the calling process (i.e if the
> + the current nesting level of the calling process (i.e. if the
> process is in init_pid_ns, nr_pids must be 1, if process is
> in a pid namespace that is a child of init-pid-ns, nr_pids
> cannot exceed 2, and so on).
>
> u32 reserved0;
> - u64 reserved1;
>
> - These fields are intended to extend the functionality of the
> + This field is intended to extend the functionality of the
> eclone() in the future, while preserving backward compatibility.
> - They must be set to 0 for now.
> + It must be set to 0 for now.
>
> The @cargs_size parameter specifes the sizeof(struct clone_args) and
> is intended to enable extending this structure in the future, while
> @@ -90,7 +89,7 @@ sys_eclone(u32 flags_low, struct clone_args * __user cargs, int cargs_size,
> namespace in which case the process is a container-init (and must have
> the pid 1 in that namespace).
>
> - See CLONE_NEWPID section of clone(2) man page for details about pid
> + See CLONE_NEWPID section of the clone(2) man page for details about pid
> namespaces.
>
> If a pid in the @pids list is 0, the kernel will assign the next
> @@ -103,8 +102,8 @@ sys_eclone(u32 flags_low, struct clone_args * __user cargs, int cargs_size,
> The order of pids in @pids is oldest in pids[0] to youngest pid
> namespace in pids[nr_pids-1]. If the number of pids specified in the
> @pids list is fewer than the nesting level of the process, the pids
> - are applied from youngest namespace. i.e if the process is nested in
> - a level-6 pid namespace and @pids only specifies 3 pids, the 3 pids
> + are applied from the youngest namespace. I.e. if the process is nested
> + in a level-6 pid namespace and @pids only specifies 3 pids, the 3 pids
> are applied to levels 6, 5 and 4. Levels 0 through 3 are assumed to
> have a pid of '0' (the kernel will assign a pid in those namespaces).
>
> @@ -119,17 +118,25 @@ sys_eclone(u32 flags_low, struct clone_args * __user cargs, int cargs_size,
> CAP_SYS_ADMIN is not required).
>
> EINVAL The number of pids specified in 'clone_args.nr_pids' exceeds
> - the current nesting level of parent process
> + the current nesting level of parent process.
>
> EINVAL Not all specified clone-flags are valid.
>
> EINVAL The reserved fields in the clone_args argument are not 0.
>
> EINVAL The child_stack_size field is not 0 (on architectures that
> - pass in a stack pointer in ->child_stack field)
> + pass in a stack pointer in ->child_stack field).
>
> EBUSY A requested pid is in use by another process in that namespace.
>
> +Following shows an example usage of eclone() on x86. To build/use eclone() with
> +other supported architectures (x86_64, ppc and s390), see the clone*[hcS] files
> +in the following git-tree.
> +
> + git://git.ncl.cs.columbia.edu/pub/git/user-cr.git
> +
> +The Makefile in the top-level directory builds a 'libeclone.a' which implements
> +the eclone() interface for the appropriate architecture.
> ---
> /*
> * Example eclone() usage - Create a child process with pid CHILD_TID1 in
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