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 we need is to teach nodemask_pr_args to handle NULL nodemask carefully. This allows simplification of both alloc_warn() and dump_header() and gets rid of pr_cont altogether. This patch has been motivated by patch from Joe Perches http://lkml.kernel.org/r/b31236dfe3fc924054fd7842bde678e71d193638.1509991345.git.joe@perches.com [[email protected]: fix tile warning, per Arnd] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Michal Hocko <[email protected]> Acked-by: Joe Perches <[email protected]> Cc: Arnd Bergmann <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
vieko · Nov 16, 2017 · 0205f75 · 0205f75
1 parent c50842c
commit 0205f75
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Showing 3 changed files with 10 additions and 18 deletions.
diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
@@ -104,7 +104,9 @@ extern nodemask_t _unused_nodemask_arg_;
  *
  * Can be used to provide arguments for '%*pb[l]' when printing a nodemask.
  */
-#define nodemask_pr_args(maskp)		MAX_NUMNODES, (maskp)->bits
+#define nodemask_pr_args(maskp)				\
+	((maskp) != NULL) ? MAX_NUMNODES : 0,		\
+	((maskp) != NULL) ? (maskp)->bits : NULL
 
 /*
  * The inline keyword gives the compiler room to decide to inline, or

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);
 	if (!IS_ENABLED(CONFIG_COMPACTION) && oc->order)
 		pr_warn("COMPACTION is disabled!!!\n");
 

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
@@ -3279,20 +3279,14 @@ 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));
 	va_end(args);
 
-	pr_cont(", mode:%#x(%pGg), nodemask=", gfp_mask, &gfp_mask);
-	if (nodemask)
-		pr_cont("%*pbl\n", nodemask_pr_args(nodemask));
-	else
-		pr_cont("(null)\n");
-
 	cpuset_print_current_mems_allowed();
 
 	dump_stack();