Re: [PATCH 06/19] mm: store mapcount for compound page separate

From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Dave Hansen <dave.hansen@intel.com>,
	Hugh Dickins <hughd@google.com>, Mel Gorman <mgorman@suse.de>,
	Rik van Riel <riel@redhat.com>, Vlastimil Babka <vbabka@suse.cz>,
	Christoph Lameter <cl@gentwo.org>,
	Steve Capper <steve.capper@linaro.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@suse.cz>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH 06/19] mm: store mapcount for compound page separate
Date: Wed, 19 Nov 2014 02:54:55 +0200	[thread overview]
Message-ID: <20141119005455.GA32179@node.dhcp.inet.fi> (raw)
In-Reply-To: <20141118234145.GA4116@hori1.linux.bs1.fc.nec.co.jp>

On Tue, Nov 18, 2014 at 11:41:08PM +0000, Naoya Horiguchi wrote:
> > > > @@ -6632,10 +6637,12 @@ static void dump_page_flags(unsigned long flags)
> > > >  void dump_page_badflags(struct page *page, const char *reason,
> > > >  		unsigned long badflags)
> > > >  {
> > > > -	printk(KERN_ALERT
> > > > -	       "page:%p count:%d mapcount:%d mapping:%p index:%#lx\n",
> > > > +	pr_alert("page:%p count:%d mapcount:%d mapping:%p index:%#lx",
> > > >  		page, atomic_read(&page->_count), page_mapcount(page),
> > > >  		page->mapping, page->index);
> > > > +	if (PageCompound(page))
> > > 
> > > > +		printk(" compound_mapcount: %d", compound_mapcount(page));
> > > > +	printk("\n");
> > > 
> > > These two printk() should be pr_alert(), too?
> > 
> > No. It will split the line into several messages in dmesg.
> 
> This splitting is fine. I meant that these printk()s are for one series
> of message, so setting the same log level looks reasonable to me.

Hm. It seems what I really need to use there is pr_cont(). I didn't know
it exists. Thanks for hint ;)

-- 
 Kirill A. Shutemov