From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f46.google.com (mail-wm0-f46.google.com [74.125.82.46]) by kanga.kvack.org (Postfix) with ESMTP id EAF7E6B0038 for ; Wed, 25 Nov 2015 09:52:04 -0500 (EST) Received: by wmuu63 with SMTP id u63so141149292wmu.0 for ; Wed, 25 Nov 2015 06:52:04 -0800 (PST) Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com. [74.125.82.51]) by mx.google.com with ESMTPS id p190si6322783wmg.80.2015.11.25.06.52.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 25 Nov 2015 06:52:03 -0800 (PST) Received: by wmww144 with SMTP id w144so72508727wmw.0 for ; Wed, 25 Nov 2015 06:52:03 -0800 (PST) Date: Wed, 25 Nov 2015 15:52:02 +0100 From: Michal Hocko Subject: Re: [PATCH v2 3/9] mm, page_owner: convert page_owner_inited to static key Message-ID: <20151125145202.GL27283@dhcp22.suse.cz> References: <1448368581-6923-1-git-send-email-vbabka@suse.cz> <1448368581-6923-4-git-send-email-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1448368581-6923-4-git-send-email-vbabka@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Vlastimil Babka Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Joonsoo Kim , Minchan Kim , Sasha Levin , "Kirill A. Shutemov" , Mel Gorman 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org