Re: [Xen-devel] [PATCH v3 05/12] xenstore: add support for reading directory with many children

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Fri, Nov 11, 2016 at 09:00:03AM +0100, Juergen Gross wrote:
> As the payload size for one xenstore wire command is limited to 4096
> bytes it is impossible to read the children names of a node with a
> large number of children (e.g. /local/domain in case of a host with
> more than about 2000 domains). This effectively limits the maximum
> number of domains a host can support.
> 
> In order to support such long directory outputs add a new wire command
> XS_DIRECTORY_PART which will return only some entries in each call and
> can be called in a loop to get all entries.
> 
> Input data are the path of the node and the byte offset into the child
> list where returned data should start.
> 
> Output is the generation count of the node (which will change each time
> the node is being modified) and a list of child names starting with
> the specified index. The end of the list is indicated by an empty
> child name. It is the responsibility of the caller to check for data
> consistency by comparing the generation counts of all returned data
> sets to be the same for one node.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>

(with Jan's comment addressed)

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