I would like to know (and I apologize if there is an obvious answer) if folks on this list have pointers to documents or discussions regarding the long-term evolution of the Linux memory manager. I realize there is plenty of shorter-term stuff to worry about, but a long-term vision would be helpful---even more so if there is some agreement. My super-simple view is that when memory reclaim is possible there is a cost attached to it, and the goal is to minimize the cost. The cost for reclaiming a unit of memory of some kind is a function of various parameters: the CPU cycles, the I/O bandwidth, and the latency, to name the main components. This function can change a lot depending on the load and in practice it may have to be grossly approximated, but the concept is valid IMO. For instance, the cost of compressing and decompressing RAM is mainly CPU cycles. A user program (a browser, for instance :) may be caching decompressed JPEGs into transcendent (discardable) memory, for quick display. In this case, almost certainly the decompressed JPEGs should be discarded before memory is compressed, under the realistic assumption that one JPEG decompression is cheaper than one LZO compression/decompression. But there may be situations in which a lot more work has gone into creating the application cache, and then it makes sense to compress/decompress it rather than discard it. It may be hard for the kernel to figure out how expensive it is to recreate the application cache, so the application should tell it. Of course, for a cache the cost needs to be multiplied by the probability that the memory will be used again in the future. A good part of the Linux VM is dedicated to estimating that probability, for some kinds of memory. But I don't see simple hooks for describing various costs such as the one I mentioned, and I wonder if this paradigm makes sense in general, or if it is peculiar to Chrome OS. Thanks! ... and Happy New Year -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>