Mirrored cache protection
AssigneePMC-Sierra US, Inc.
InventorsJonathan Flower, Nadesan Narenthiran
Life of this patent
Estimating the term…
Abstract
Methods of protecting cache data are provided. For example, various methods are described that assist in handling dirty write data cached in memory by duplication into other locations to protect against data loss. One method includes caching a data item from a data source in a first cache device. The data item cached in the first cache device is designated with a first designation. In response to the data item being modified by a data consumer, the designation of the data item in the first cache device is re-assigned from the first designation to a second designation, and the data item with the second designation is copied to a second cache device.
Claims20
A method of cache data redundancy, comprising:
- providing a plurality of cache devices, wherein each of the plurality of cache devices is partitioned into a first allocated area and a second allocated area, the first allocated area being used for storing data items that are in an unmodified form and the second allocated area being used for storing data items that are in a modified form;
- copying a data item from a data source to the first allocated area in one of the plurality of cache devices, the data item being in the unmodified form;
- in response to the data item being modified by a data consumer,
- (a) logically removing the data item from the first allocated area of one of the plurality of cache devices;
- (b) copying the data item in the modified form to the second allocated area in one of the plurality of cache devices;
- and
- transferring the data item in the modified form from the second allocated area of one of the plurality of cache devices to the data source, in response to the transferring to the data source, copying the data item in the modified form from the second allocated area of the one of the plurality of cache devices to the first allocated area of one of the plurality of cache devices.
A method of protecting cache data, comprising:
- caching a data item from a data source in a first cache device;
- designating the data item in the first cache device with a first designation;
- in response to the data item being modified by a data consumer, re-assigning the designation of the data item in the first cache device from the first designation to a second designation;
- and
- copying the data item with the second designation to a second cache device, wherein the first designation used to associate state information related to an unmodified form of the data item and the second designation used to associate state information related to a modified form of the data item, in response to the copying, re-initializing the data item in the first cache device, the re-initializing changing the designation of the data item from the second designation to the first designation.
A system for protecting cache data comprising:
- a data source operable to store a data item;
- a data consumer operable to request the data item stored in the data source, the data consumer further operable to modify the data item;
- and
- a plurality of cache devices, each of the plurality of cache devices partitioned into a first allocated area and a second allocated area, the plurality of cache devices including,
- a first cache device operable to copy the data item stored in the data source into the first allocated area that is used for storing data in unmodified form, and designate the data item in an unmodified state with a first designation, the first cache device further operable to modify the designation of the data item in a modified state to a second designation in response to the data item being modified by the data consumer;
- and
- a second cache device operable to store the copy of the data item with the second designation in the second allocation area that is used for storing data in modified form, wherein the first designation is used to associate state information related to an unmodified form of the data item and the second designation is used to associate state information related to a modified form of the data item and wherein the second cache device is further operable to transfer the data item in the modified form to the data source and to copy the data item in the modified form from the second allocated area to the first allocated area of any one of the plurality of cache devices, the copying causes re-initializing of the data item from second designation to the first designation in the first allocated area.
Dependencies are inferred from the claim text.