Il 14/11/2012 03:14, Isaku Yamahata ha scritto: >> > Identifying ballooned zero pages is useful, because those cause the >> > clear_page calls in the kernel even in a guest that has been running for >> > a while. >> > >> > But a generic solution doesn't really matter, because is_dup_page and >> > clear_page shouldn't really be in the profile in practice, except in >> > microbenchmarks. > I guess mincore(2) can be used as easy way to detect non-mapped page. > This is just implementation detail anyway.
Doesn't work if the page is swapped, doesn't it? But I wonder if the clear_page occurrences are because of the problem described recently on LWN (http://lwn.net/Articles/517465/), and so really more of a kernel bug than anything else. Paolo
