On Thu, 5 Nov 2015, Michal Hocko wrote: > > diff --git a/fs/proc/base.c b/fs/proc/base.c > > --- a/fs/proc/base.c > > +++ b/fs/proc/base.c > > @@ -1032,6 +1032,16 @@ static ssize_t oom_adj_read(struct file *file, char > > __user *buf, size_t count, > > return simple_read_from_buffer(buf, count, ppos, buffer, len); > > } > > > > +/* > > + * /proc/pid/oom_adj exists solely for backwards compatibility with > > previous > > + * kernels. The effective policy is defined by oom_score_adj, which has a > > + * different scale: oom_adj grew exponentially and oom_score_adj grows > > linearly. > > + * Values written to oom_adj are simply mapped linearly to oom_score_adj. > > + * Processes that become oom disabled via oom_adj will still be oom > > disabled > > + * with this implementation. > > + * > > + * oom_adj cannot be removed since existing userspace binaries use it. > > This is a bit strong wording. I think the knob can be removed in the future. >
Perhaps you are my optimistic than I am, but I would think it would be difficult to remove a tunable that requires binaries to be re-built to avoid. That was Linus's primary objection, IIRC. If an application fails to oom disable itself because it still writes to oom_adj, the results could be a system wide failure. There are workarounds to that if you have root, but I don't think we're in a position to remove it in the near future. I think the comment is clear why it cannot be removed right now and its current implementation. Converting software that writes to oom_adj to use oom_score_adj instead is still a worthwhile goal, though, since they'd be using the semantics of the effective policy. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/