On Thu, Mar 02, 2023 at 05:36:20PM -0500, Rik van Riel wrote: > > The questions, do we have this indirection layer apply to all swap > > entries? > > > I believe we should have a system that tracks every swap entry > the same, data structure wise. Otherwise we will have two sets > of code in the kernel, and it will be too easy to get corner > cases wrong. It is all about trade offs. The original proposal is adding 20-30 bytes per swapped out page, compared to existing swap devices. That is why I want to trade some code complexity for less memory usage. I will mind less if indirect overhead is much smaller, for the user who doesn't use it. > > > That might be a net reduction in the code over what we have today, > > > because it gets rid of some ugly corner cases. > > > > Great. > > ... but that won't happen if the indirection layer only applies > to some swap devices, because we will still need to keep around > the crazy code to deal with the swap devices that don't have it. I understand your concern. It is important to have good abstraction between the different swap devices. I was hoping to good abstraction can isolate out the difference in different swap devices. Chris
