On Mon, Nov 19, 2012 at 09:52:11PM -0800, Andrew Morton wrote: > On Wed, 7 Nov 2012 03:01:52 -0800 Anton Vorontsov <anton.vorontsov@xxxxxxxxxx> wrote: > > Upon these notifications, userland programs can cooperate with > > the kernel, achieving better system's memory management. > > Well I read through the whole thread and afaict the above is the only > attempt to describe why this patchset exists! Thanks for taking a look. :) > How about we step away from implementation details for a while and > discuss observed problems, use-cases, requirements and such? What are > we actually trying to achieve here? We try to make userland freeing resources when the system becomes low on memory. Once we're short on memory, sometimes it's better to discard (free) data, rather than let the kernel to drain file caches or even start swapping. In Android case, the data includes all idling applications' state, some of which might be saved on the disk anyway -- so we don't need to swap apps, we just kill them. Another Android use-case is to kill low-priority tasks (e.g. currently unimportant services -- background/sync daemons, etc.). There are other use cases: VPS/containers balancing, freeing browser's old pages renders on desktops, etc. But I'll let folks speak for their use cases, as I truly know about Android/embedded only. But in general, it's the same stuff as the in-kernel shrinker, except that we try to make it available for the userland: the userland knows better about its memory, so we want to let it help with the memory management. Thanks, Anton. -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>