Hi, this is an updated version of the patchset previous posted here: http://marc.info/?l=linux-mm&m=141779771518056&w=2. Changes since then are: - cleanups, doc and function renames as per Tejun - __thaw_task moved to mark_tsk_oom_victim and frozen() check removed as it would be racy and it is not necessary anyway - per Tejun - obvious typo in wait_event condition - oom_killer_enable moved to thaw_processes before user tasks are thawed rather than thaw_kernel_threads which is even not called from s2ram resume path - per Tejun - oom_killer_disable moved to freeze_processes to be more in sync with the enable. I have tested the series in KVM with 100M RAM: - many small tasks (20M anon mmap) which are triggering OOM continually - s2ram which resumes automatically is triggered in a loop echo processors > /sys/power/pm_test while true do echo mem > /sys/power/state sleep 1s done - simple module which allocates and frees 20M in 8K chunks. If it sees freezing(current) then it tries another round of allocation before calling try_to_freeze - debugging messages of PM stages and OOM killer enable/disable/fail added and unmark_oom_victim is delayed by 1s after it clears TIF_MEMDIE and before it wakes up waiters. - rebased on top of the current mmotm which means some necessary updates in mm/oom_kill.c. mark_tsk_oom_victim is now called under task_lock but I think this should be OK because __thaw_task shouldn't interfere with any locking down wake_up_process. Oleg? As expected there are no OOM killed tasks after oom is disabled and allocations requested by the kernel thread are failing after all the tasks are frozen and OOM disabled. I wasn't able to catch a race where oom_killer_disable would really have to wait but I kinda expected the race is really unlikely. [ 242.609330] Killed process 2992 (mem_eater) total-vm:24412kB, anon-rss:2164kB, file-rss:4kB [ 243.628071] Unmarking 2992 OOM victim. oom_victims: 1 [ 243.636072] (elapsed 2.837 seconds) done. [ 243.641985] Trying to disable OOM killer [ 243.643032] Waiting for concurent OOM victims [ 243.644342] OOM killer disabled [ 243.645447] Freezing remaining freezable tasks ... (elapsed 0.005 seconds) done. [ 243.652983] Suspending console(s) (use no_console_suspend to debug) [ 243.903299] kmem_eater: page allocation failure: order:1, mode:0x204010 [...] [ 243.992600] PM: suspend of devices complete after 336.667 msecs [ 243.993264] PM: late suspend of devices complete after 0.660 msecs [ 243.994713] PM: noirq suspend of devices complete after 1.446 msecs [ 243.994717] ACPI: Preparing to enter system sleep state S3 [ 243.994795] PM: Saving platform NVS memory [ 243.994796] Disabling non-boot CPUs ... The first 2 patches are simple cleanups for OOM. They should go in regardless the rest IMO. Patches 3 and 4 are trivial printk -> pr_info conversion and they should go in ditto. The main patch is the last one and I would appreciate acks from Tejun and Rafael. I think the OOM part should be OK (except for __thaw_task vs. task_lock where a look from Oleg would appreciated) but I am not so sure I haven't screwed anything in the freezer code. I have found several surprises there. The patchset is based on the current mmotm tree (mmotm-2015-01-07-17-07). I think it make more sense if it is routed via Andrew due to dependences on other OOM killer patches. Shortlog says: Michal Hocko (5): oom: add helpers for setting and clearing TIF_MEMDIE oom: thaw the OOM victim if it is frozen PM: convert printk to pr_* equivalent sysrq: convert printk to pr_* equivalent oom, PM: make OOM detection in the freezer path raceless And diffstat: drivers/staging/android/lowmemorykiller.c | 7 +- drivers/tty/sysrq.c | 23 ++--- include/linux/oom.h | 18 ++-- kernel/exit.c | 3 +- kernel/power/process.c | 76 +++++---------- mm/memcontrol.c | 4 +- mm/oom_kill.c | 149 ++++++++++++++++++++++++++---- mm/page_alloc.c | 17 +--- 8 files changed, 185 insertions(+), 112 deletions(-) -- 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>