Re: [PATCH 1/6] mm/page_alloc: use appropriate printk priority level

On 01/27/2011 05:22 PM, Mandeep Singh Baines wrote:

Ryan Mallon (ryan@bluewatersys.com) wrote:

quoted

On 01/27/2011 12:29 PM, Mandeep Singh Baines wrote:

quoted

printk()s without a priority level default to KERN_WARNING. To reduce
noise at KERN_WARNING, this patch set the priority level appriopriately
for unleveled printks()s. This should be useful to folks that look at
dmesg warnings closely.

Signed-off-by: Mandeep Singh Baines <redacted>
---

quoted

@@ -4700,33 +4700,36 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
 	find_zone_movable_pfns_for_nodes(zone_movable_pfn);
 
 	/* Print out the zone ranges */
-	printk("Zone PFN ranges:\n");
+	printk(KERN_INFO "Zone PFN ranges:\n");
 	for (i = 0; i < MAX_NR_ZONES; i++) {
 		if (i == ZONE_MOVABLE)
 			continue;
-		printk("  %-8s ", zone_names[i]);
+		printk(KERN_INFO "  %-8s ", zone_names[i]);
 		if (arch_zone_lowest_possible_pfn[i] ==
 				arch_zone_highest_possible_pfn[i])
 			printk("empty\n");

Should be printk(KERN_CONT ... (or pr_cont).

quoted

 		else
-			printk("%0#10lx -> %0#10lx\n",
+			printk(KERN_INFO "%0#10lx -> %0#10lx\n",
 				arch_zone_lowest_possible_pfn[i],
 				arch_zone_highest_possible_pfn[i]);

The printk above doesn't have a trailing newline so this should be
printk(KERN_CONT ...

There are a couple of other places in this patch series that also need
to be fixed in a similar manner.

D'oh. Good catch;)

The KERN_INFO here was unintentional. I had intended to leave it out.
The code I was looking at as a reference was just omitting KERN_ for
continuations. But I take it that the convention is to use KERN_CONT.
I'll fixup the patch series to use that.

I think in general it is nicer to use KERN_CONT because it explicitly
shows that there is a printk somewhere above with no trailing newline.

Note that include/linux/printk.h has this to say about KERN_CONT:

/*
 * Annotation for a "continued" line of log printout (only done after a
 * line that had no enclosing \n). Only to be used by core/arch code
 * during early bootup (a continued line is not SMP-safe otherwise).
 */

I'm guessing that the above is safe, but if you are fixing printks up
then it would be good to check that places using continued lines are safe.

I tried to use pr_ wherever the file was already using it or where I was
changing all printk()s. For files with many printk()s I just continued
using printk() to keep the patch small and also to avoid mixing printk
with pr_. However, if it is preferrable, I'm happy to replace all printk()s
with pr_ in the files I touch in the series.

I'm not sure what the policy on changing printk to the pr_ variants is.
Cc'ed Joe Perches who knows more about such things.

~Ryan

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