On Thu, 2017-11-09 at 11:05 +0100, Michal Hocko wrote:
[]
> Subject: [PATCH] mm: simplify nodemask printing
>
> alloc_warn and dump_header have to explicitly handle NULL nodemask which
> forces both paths to use pr_cont. We can do better. printk already
> handles NULL pointers properly so all what we need is to teach
> nodemask_pr_args to handle NULL nodemask carefully. This allows
> simplification of both alloc_warn and dump_header and get rid of pr_cont
> altogether.
[]
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
[]
> @@ -426,14 +426,10 @@ static void dump_tasks(struct mem_cgroup *memcg, const
> nodemask_t *nodemask)
>
> static void dump_header(struct oom_control *oc, struct task_struct *p)
> {
> - pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), nodemask=",
> - current->comm, oc->gfp_mask, &oc->gfp_mask);
> - if (oc->nodemask)
> - pr_cont("%*pbl", nodemask_pr_args(oc->nodemask));
> - else
> - pr_cont("(null)");
> - pr_cont(", order=%d, oom_score_adj=%hd\n",
> - oc->order, current->signal->oom_score_adj);
> + pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), nodemask=%*pbl,
> order=%d, oom_score_adj=%hd\n",
> + current->comm, oc->gfp_mask, &oc->gfp_mask,
> + nodemask_pr_args(oc->nodemask), oc->order,
> + current->signal->oom_score_adj);
trivia:
You could align the arguments to the open parenthesis here
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
[]
> @@ -3281,20 +3281,14 @@ void warn_alloc(gfp_t gfp_mask, nodemask_t *nodemask,
> const char *fmt, ...)
> if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs))
> return;
>
> - pr_warn("%s: ", current->comm);
> -
> va_start(args, fmt);
> vaf.fmt = fmt;
> vaf.va = &args;
> - pr_cont("%pV", &vaf);
> + pr_warn("%s: %pV, mode:%#x(%pGg), nodemask=%*pbl\n",
> + current->comm, &vaf, gfp_mask, &gfp_mask,
> + nodemask_pr_args(nodemask));
and here
