On Mon, 5 Apr 2010, Andrew Morton wrote: > > This patch applies cleanly on mmotm-2010-03-24-14-48 and I don't see > > anything that has been added since then that touches > > mem_cgroup_out_of_memory(). > > I'm working on another mmotm at present. > Nothing else you've merged since mmotm-2010-03-24-14-48 has touched mem_cgroup_out_of_memory() that I've been cc'd on. This patch should apply cleanly. > > I haven't seen any outstanding compatibility issues raised. The only > > thing that isn't backwards compatible is consolidating > > /proc/sys/vm/oom_kill_allocating_task and /proc/sys/vm/oom_dump_tasks into > > /proc/sys/vm/oom_kill_quick. We can do that because we've enabled > > oom_dump_tasks by default so that systems that use both of these tunables > > need to now disable oom_dump_tasks to avoid the costly tasklist scan. > > This can break stuff, as I've already described - if a startup tool is > correctly checking its syscall return values and a /procfs file > vanishes, the app may bail out and not work. > This is not the first time we have changed or obsoleted tunables in /proc/sys/vm. If a startup tool really is really bailing out depending on whether echo 1 > /proc/sys/vm/oom_kill_allocating_task succeeds, it should be fixed regardless because you're not protecting anything by doing that since you can't predict what task is allocating memory at the time of oom. Those same startup tools will need to disable /proc/sys/vm/oom_dump_tasks if we are to remove the consolidation into oom_kill_quick and maintain two seperate VM sysctls that are always used together by the same users. Nobody can even cite a single example of oom_kill_allocating_task being used in practice, yet we want to unnecessarily maintain these two seperate sysctls forever because it's possible that a buggy startup tool cares about the return value of enabling it? > Others had other objections, iirc. > I'm all ears. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>