On Wed, 2007-06-06 at 00:48 -0700, David Rientjes wrote: > On Wed, 6 Jun 2007, Paul Jackson wrote: > > > Seems like that mlock code is able then to get great globs of memory > > without returning to user space ... perhaps that's where the fix > > should be ... that code should quit chewing up memory if it's > > marked MEMDIE or some such? > > > > That's one case. Are there others? > > The TIF_MEMDIE exception in cpuset_zone_allowed_softwall() allowed this > problem in mlock(). If it had not been allowed to allocate anywhere > based simply on the zonelist ordering, the mlock iteration would break > because it could not handle the fault. > > Thus, at the least, we should make sure that memory is not allocated > outside of a task's mems_allowed unless we do sanity checks against > gfp_mask in the TIF_MEMDIE case via cpuset_zone_allowed_softwall() to make > sure a rouge application doesn't cause the same trouble. That is, unless > you can guarantee this type of problem will not happen again through any > other means. The logic needs to be with the TIF_MEMDIE exception to grant > access to memory outside the cpuset only when it is relevant to the OOM > killed task's prompt exit.
I don't think your patch alone would have been sufficient. With it it would have depleted the local reserves and then jumped onwards to other nodes (since the ALLOC_NO_WATERMARKS allocation doesn't have ALLOC_CPUSET). Unless there was a mem-policy restricting the zonelist (not sure if cpusets and mem-policies are independent like that) But your point stands. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
