> Changes > ------- > > This is v2 of the BPF OOM policy patchset. > v1 : https://lore.kernel.org/lkml/20230804093804.47039-1-zhouchuyi@xxxxxxxxxxxxx/ > v1 -> v2 changes: > > - rename bpf_select_task to bpf_oom_evaluate_task and bypass the > tsk_is_oom_victim (and MMF_OOM_SKIP) logic. (Michal) > > - add a new hook to set policy's name, so dump_header() can know > what has been the selection policy when reporting messages. (Michal) > > - add a tracepoint when select_bad_process() find nothing. (Alan) > > - add a doc to to describe how it is all supposed to work. (Alan) > > ================ > > This patchset adds a new interface and use it to select victim when OOM > is invoked. The mainly motivation is the need to customizable OOM victim > selection functionality. > > The new interface is a bpf hook plugged in oom_evaluate_task. It takes oc > and current task as parameters and return a result indicating which one is > selected by the attached bpf program. > > There are several conserns when designing this interface suggested by > Michal: > > 1. Hooking into oom_evaluate_task can keep the consistency of global and > memcg OOM interface. Besides, it seems the least disruptive to the existing > oom killer implementation. > > 2. Userspace can handle a lot on its own and provide the input to the BPF > program to make a decision. Since the oom scope iteration will be > implemented already in the kernel so all the BPF program has to do is to > rank processes or memcgs. > > 3. The new interface should better bypass the current heuristic rules > (e.g., tsk_is_oom_victim, and MMF_OOM_SKIP) to meet an arbitrary oom > policy's need. Can we linux-mm on such changes? I almost missed this series :)
