Yunsheng Lin <linyunsheng@xxxxxxxxxx> writes: >> But, well, I'm not sure it is? You seem to be taking it as axiomatic >> that the wait in itself is bad. Why? It's just a bit memory being held >> on to while it is still in use, and so what? > > Actually, I thought about adding some sort of timeout or kicking based on > jakub's waiting patch too. > > But after looking at more caching in the networking, waiting and kicking/flushing > seems harder than recording the inflight pages, mainly because kicking/flushing > need very subsystem using page_pool owned page to provide a kicking/flushing > mechanism for it to work, not to mention how much time does it take to do all > the kicking/flushing. Eliding the details above, but yeah, you're right, there are probably some pernicious details to get right if we want to flush all caches. S I wouldn't do that to start with. Instead, just add the waiting to start with, then wait and see if this actually turns out to be a problem in practice. And if it is, identify the source of that problem, deal with it, rinse and repeat :) -Toke
