These day, there are many platforms avaiable in the embedded market and they are smarter than kernel which has very limited information about working set so they want to involve memory management more heavily like android's lowmemory killer and ashmem or recent many lowmemory notifier(there was several trial for various company NOKIA, SAMSUNG, Linaro, Google ChromeOS, Redhat). One of the simple imagine scenario about userspace's intelligence is that platform can manage tasks as forground and backgroud so it would be better to reclaim background's task pages for end-user's *responsibility* although it has frequent referenced pages. The patch[1] prepares that force_reclaim in shrink_page_list can handle anonymous pages as well as file-backed pages. The patch[2] adds new knob "reclaim under proc/<pid>/" so task manager can reclaim any target process anytime, anywhere. It could give another method to platform for using memory efficiently. It can avoid process killing for getting free memory, which was really terrible experience because I lost my best score of game I had ever after I switch the phone call while I enjoyed the game. Reclaim file-backed pages only. echo file > /proc/PID/reclaim Reclaim anonymous pages only. echo anon > /proc/PID/reclaim Reclaim all pages echo all > /proc/PID/reclaim Some pages could be shared by several processes. (ex, libc) In case of that, it's too bad to reclaim them from the beginnig. The patch[5] causes VM to keep them on memory until last task try to reclaim them so shared pages will be reclaimed only if all of task has gone swapping out. Another requirement is per address space reclaim.(By Michael Kerrisk) In case of Webkit1, it uses a address space for handling multi tabs. IOW, it uses *one* process model so all tabs shares address space of the process. In such scenario, per-process reclaim is rather coarse-grained so patch[6] supports more fine-grained reclaim for being able to reclaim target address range of the process. For reclaim target range, you should use following format. echo [addr] [size-byte] > /proc/pid/reclaim * Changelog from v4 * Fix anonymous page write out - Minkyung Kim * Changelog from v3 * Rebased on next-20130508 * Minor change * Changelog from v2 * Use memparse - Namhung Kim * Add Acked-by * Changelog from v1 * Change reclaim knob interface - Dave Hansen * proc.txt document change - Rob Landley Minchan Kim (7): [1] mm: prevent to write out dirty page in CMA by may_writepage [2] mm: Per process reclaim [3] mm: make shrink_page_list with pages work from multiple zones [4] mm: Remove shrink_page [5] mm: Enhance per process reclaim to consider shared pages [6] mm: Support address range reclaim [7] add documentation about reclaim knob on proc.txt Documentation/filesystems/proc.txt | 20 +++++ fs/proc/base.c | 3 + fs/proc/internal.h | 1 + fs/proc/task_mmu.c | 176 +++++++++++++++++++++++++++++++++++++ include/linux/ksm.h | 6 +- include/linux/rmap.h | 10 ++- mm/Kconfig | 16 ++++ mm/ksm.c | 9 +- mm/memory-failure.c | 2 +- mm/migrate.c | 6 +- mm/rmap.c | 57 ++++++++---- mm/vmscan.c | 62 ++++++++++++- 12 files changed, 340 insertions(+), 28 deletions(-) -- 1.8.2.1 -- 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>