On 12/14/2016 12:59 AM, Li, Liang Z wrote: >> Subject: Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for >> fast (de)inflating & fast live migration >> >> On 12/08/2016 08:45 PM, Li, Liang Z wrote: >>> What's the conclusion of your discussion? It seems you want some >>> statistic before deciding whether to ripping the bitmap from the ABI, >>> am I right? >> >> I think Andrea and David feel pretty strongly that we should remove the >> bitmap, unless we have some data to support keeping it. I don't feel as >> strongly about it, but I think their critique of it is pretty valid. I think the >> consensus is that the bitmap needs to go. >> >> The only real question IMNHO is whether we should do a power-of-2 or a >> length. But, if we have 12 bits, then the argument for doing length is pretty >> strong. We don't need anywhere near 12 bits if doing power-of-2. > > Just found the MAX_ORDER should be limited to 12 if use length instead of order, > If the MAX_ORDER is configured to a value bigger than 12, it will make things more > complex to handle this case. > > If use order, we need to break a large memory range whose length is not the power of 2 into several > small ranges, it also make the code complex. I can't imagine it makes the code that much more complex. It adds a for loop. Right? > It seems we leave too many bit for the pfn, and the bits leave for length is not enough, > How about keep 45 bits for the pfn and 19 bits for length, 45 bits for pfn can cover 57 bits > physical address, that should be enough in the near feature. > > What's your opinion? I still think 'order' makes a lot of sense. But, as you say, 57 bits is enough for x86 for a while. Other architectures.... who knows? -- 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>