Emc IP Holding Company LLC

Emc Corporation

Fenghua Hu

Junping Zhao

Wei Qi

Jialin Yang

Gang Xie

Kevin Xu

Embodiments of the present invention relate to a method, apparatus and computer product for managing memory space. In one aspect of the present invention, there is provided a method for managing memory space that is organized into pages, the pages being divided into a plurality of page sets, each page set being associated with one of a plurality of upper-layer systems, by: performing state monitoring to the plurality of upper-layer systems to assign priorities to the plurality of upper-layer systems; and determining an order of releasing the pages of the memory space based on the priorities of the plurality of upper-layer systems with the page sets as units. Other aspects and embodiments of invention are also disclosed.

Method and apparatus for managing memory space

A technique manages access to a B-tree structure within a data storage apparatus. The B-tree structure maintains mappings of data blocks of a file system to data blocks of a snapshot storage area. The technique involves imposing a lock on the B-tree structure in response to a snapshot operation which copies a contiguous range of file system data blocks to a set of snapshot data blocks to save primary data of the file system as snapshot data. The technique further involves inserting multiple objects into the B-tree structure while the lock is imposed, each object including a key value which (i) identifies a respective file system data block of the contiguous range and (ii) operates as a search key to facilitate searching of nodes of the B-tree structure. The technique further involves releasing the lock imposed on the B-tree structure after the objects have been inserted into the B-tree structure.

Efficient extent-based B-tree insertion

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Beijing, China

Fenghua Hu