Systems and methods for retiring and unretiring cache lines

摘要

The systems and methods described herein may provide a flush-retire instruction for retiring “bad” cache locations (e.g., locations associated with persistent errors) to prevent their allocation for any further accesses, and a flush-unretire instruction for unretiring cache locations previously retired. These instructions may be implemented as hardware instructions of a processor. They may be executable by processes executing in a hyper-privileged state, without the need to quiesce any other processes. The flush-retire instruction may atomically flush a cache line implicated by a detected cache error and set a lock bit to disable subsequent allocation of the corresponding cache location. The flush-unretire instruction may atomically flush an identified cache line (if valid) and clear the lock bit to re-enable subsequent allocation of the cache location. Various bits in the encodings of these instructions may identify the cache location to be retired or unretired in terms of the physical cache structure.

主权项

1. A method, comprising:
performing, by a computer:
detecting an error in a cache, wherein the error is associated with a particular cache line; andin response to said detecting, executing a flush-retire instruction, wherein the flush-retire instruction is a single hardware instruction of an instruction set architecture of a processor of the computer, and wherein said executing causes the computer to atomically perform:
flushing the cache line to memory; anddisabling subsequent allocation of a cache location that held the cache line.