Techniques for reducing read i/o latency in virtual machines

A non-transitory computer readable storage medium containing instructions for reducing the latency of an anticipated read of disk blocks from a swap file in a virtualized environment, the environment including:

• a host swap file maintained by a host operating system and a virtual machine (VM) that includes a guest swap file maintained by a guest operating system, the instructions when executed, control a computer system to be configured for:
• identifying, in the guest swap file, a sequence of disk blocks that was written by the guest operating system;
• detecting, within the sequence of disk blocks, a first reference to a first disk block stored in the host swap file;
• detecting, within the sequence of disk blocks, a second reference to a second disk block stored in the host swap file;
• and
• moving the second disk block to a location in the host swap file adjacent to the first disk block.

An apparatus for reducing the latency of an anticipated read of disk blocks from a swap file in a virtualized environment, the environment including:

• a host swap file maintained by a host operating system and a virtual machine (VM) that includes a guest swap file maintained by a guest operating system, the apparatus comprising:
• one or more computer processors;
• and
• a non-transitory computer-readable storage medium comprising instructions, that when executed, control the one or more computer processors to be configured for:
• identifying, in the guest swap file, a sequence of disk blocks that was written by the guest operating system;
• detecting, within the sequence of disk blocks, a first reference to a first disk block stored in the host swap file;
• detecting, within the sequence of disk blocks, a second reference to a second disk block stored in the host swap file;
• and
• moving the second disk block to a location in the host swap file adjacent to the first disk block.