On Tue, May 28, 2019 at 11:08:21AM +0200, Michal Hocko wrote: > On Tue 28-05-19 17:49:27, Minchan Kim wrote: > > On Tue, May 28, 2019 at 01:31:13AM -0700, Daniel Colascione wrote: > > > On Tue, May 28, 2019 at 1:14 AM Minchan Kim <minchan@xxxxxxxxxx> wrote: > > > > if we went with the per vma fd approach then you would get this > > > > > feature automatically because map_files would refer to file backed > > > > > mappings while map_anon could refer only to anonymous mappings. > > > > > > > > The reason to add such filter option is to avoid the parsing overhead > > > > so map_anon wouldn't be helpful. > > > > > > Without chiming on whether the filter option is a good idea, I'd like > > > to suggest that providing an efficient binary interfaces for pulling > > > memory map information out of processes. Some single-system-call > > > method for retrieving a binary snapshot of a process's address space > > > complete with attributes (selectable, like statx?) for each VMA would > > > reduce complexity and increase performance in a variety of areas, > > > e.g., Android memory map debugging commands. > > > > I agree it's the best we can get *generally*. > > Michal, any opinion? > > I am not really sure this is directly related. I think the primary > question that we have to sort out first is whether we want to have > the remote madvise call process or vma fd based. This is an important > distinction wrt. usability. I have only seen pid vs. pidfd discussions > so far unfortunately. With current usecase, it's per-process API with distinguishable anon/file but thought it could be easily extended later for each address range operation as userspace getting smarter with more information.
