On Sun, 2011-10-30 at 12:18 -0700, Dan Magenheimer wrote: > > since they're the ones who will have to understand this stuff and know > > how to maintain it. And keeping this maintainable is a key goal. > > Absolutely agree. Count the number of frontswap lines that affect > the current VM core code and note also how they are very clearly > identified. It really is a very VERY small impact to the core VM > code (e.g. in the files swapfile.c and page_io.c). Granted, the impact on the core VM in lines of code is small. But, I think the behavioral impact is potentially huge since tmem's hooks add non-trivial amounts of framework underneath the VM in core paths. In zcache's case, this means a bunch of allocations and an entirely new allocator memory allocator being used in the swap paths. We're certainly still shaking bugs out of the interactions there like with zcache_direct_reclaim_lock. Granted, that's not a tmem/frontswap/cleancache bug, but it does speak to the difficulty and subtlety of writing one of those frameworks underneath the tmem API. -- Dave -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>