linux-kernel - Re: Question about printking

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Date:	Sat, 02 Feb 2013 11:43:31 -0800
From:	Joe Perches <joe@...ches.com>
To:	Ezequiel Garcia <elezegarcia@...il.com>
Cc:	gregkh <gregkh@...uxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Dan Carpenter <dan.carpenter@...cle.com>,
	kernelnewbies <kernelnewbies@...nelnewbies.org>,
	kernel-janitors@...r.kernel.org,
	linux-media <linux-media@...r.kernel.org>,
	devel@...verdev.osuosl.org
Subject: Re: Question about printking

On Sat, 2013-02-02 at 16:30 -0300, Ezequiel Garcia wrote:
> ptr = kmalloc(sizeof(foo));
> if (!ptr) {
>         pr_err("Cannot allocate memory for foo\n");
>         return -ENOMEM;
> }
> His argue against it was that kmalloc already takes care of reporting/printking
> a good deal of interesting information when this happens.

> Can someone expand a bit on this whole idea? (of abuse of printing,
> or futility of printing).

k.alloc() takes a GFP_ flag as an arg.

One of those GFP flags is __GFP_NOWARN.

For all failed allocs without GFP_NOWARN
a message is emitted and a dump_stack is
done.

(see: mm/page_alloc.c warn_alloc_failed())

So, most all of these printks after
k.alloc()'s are not necessary.


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