Date: Wed, 25 Nov 2015 15:52:02 +0100
From: Michal Hocko <mhocko@kernel.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, Minchan Kim <minchan@kernel.org>,
        Sasha Levin <sasha.levin@oracle.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Mel Gorman <mgorman@suse.de>
Subject: Re: [PATCH v2 3/9] mm, page_owner: convert page_owner_inited to
 static key
Message-ID: <20151125145202.GL27283@dhcp22.suse.cz>
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On Tue 24-11-15 13:36:15, Vlastimil Babka wrote:
> CONFIG_PAGE_OWNER attempts to impose negligible runtime overhead when enabled
> during compilation, but not actually enabled during runtime by boot param
> page_owner=on. This overhead can be further reduced using the static key
> mechanism, which this patch does.

Is this really worth doing? If we do not have jump labels then the check
will be atomic rather than a simple access, so it would be more costly,
no? Or am I missing something?
-- 
Michal Hocko
SUSE Labs
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