> Both the RFC patch and the above 5-step recovery plan look neat, step 4) > is nice to carry forward on icelake when a single instruction to clear > poison is available. Jane, Clearing poison has some challenges. On persistent memory it probably works (as the DIMM is going to remap that address to a different part of the media to avoid the bad spot). On DDR memory you'd need to decide whether the problem was transient, so that a simple overwrite fixes the problem. Or persistent ... in which case the problem will likely come back with the right data pattern. To tell that you may need to run some memory test on the affected area. If the error was just in a 4K page, I'd be inclined to copy the good data to a new page and map that in instead. Throwing away one 4K page isn't likely to be painful. If it is in a 2M/1G page ... perhaps it is worth the effort and risk of trying to clear the poison in place to avoid the pain of breaking up a large page. -Tony
