On Tue 10-04-18 11:41:44, Zhaoyang Huang wrote: > On Tue, Apr 10, 2018 at 11:12 AM, Steven Rostedt <rost...@goodmis.org> wrote: > > On Tue, 10 Apr 2018 10:32:36 +0800 > > Zhaoyang Huang <huangzhaoy...@gmail.com> wrote: > > > >> For bellowing scenario, process A have no intension to exhaust the > >> memory, but will be likely to be selected by OOM for we set > >> OOM_CORE_ADJ_MIN for it. > >> process A(-1000) process B > >> > >> i = si_mem_available(); > >> if (i < nr_pages) > >> return -ENOMEM; > >> schedule > >> ---------------> > >> allocate huge memory > >> <------------- > >> if (user_thread) > >> set_current_oom_origin(); > >> > >> for (i = 0; i < nr_pages; i++) { > >> bpage = kzalloc_node > > > > Is this really an issue though? > > > > Seriously, do you think you will ever hit this? > > > > How often do you increase the size of the ftrace ring buffer? For this > > to be an issue, the system has to trigger an OOM at the exact moment > > you decide to increase the size of the ring buffer. That would be an > > impressive attack, with little to gain. > > > > Ask the memory management people. If they think this could be a > > problem, then I'll be happy to take your patch. > > > > -- Steve > add Michael for review. > Hi Michael, > I would like suggest Steve NOT to set OOM_CORE_ADJ_MIN for the process > with adj = -1000 when setting the user space process as potential > victim of OOM.
OOM_SCORE_ADJ_MIN means "hide the process from the OOM killer completely". So what exactly do you want to achieve here? Because from the above it sounds like opposite things. /me confused... -- Michal Hocko SUSE Labs