From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) by kanga.kvack.org (Postfix) with ESMTP id 688AC6B026D for ; Mon, 5 Nov 2018 04:26:45 -0500 (EST) Received: by mail-ed1-f71.google.com with SMTP id x1-v6so4893801edh.8 for ; Mon, 05 Nov 2018 01:26:45 -0800 (PST) Received: from outbound-smtp25.blacknight.com (outbound-smtp25.blacknight.com. [81.17.249.193]) by mx.google.com with ESMTPS id h4-v6si3933260ejx.88.2018.11.05.01.26.44 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 05 Nov 2018 01:26:44 -0800 (PST) Received: from mail.blacknight.com (pemlinmail03.blacknight.ie [81.17.254.16]) by outbound-smtp25.blacknight.com (Postfix) with ESMTPS id E2D22B8750 for ; Mon, 5 Nov 2018 09:26:43 +0000 (GMT) Date: Mon, 5 Nov 2018 09:26:42 +0000 From: Mel Gorman Subject: Re: [PATCH 1/2] mm/page_alloc: free order-0 pages through PCP in page_frag_free() Message-ID: <20181105092642.GF23537@techsingularity.net> References: <20181105085820.6341-1-aaron.lu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20181105085820.6341-1-aaron.lu@intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Aaron Lu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Andrew Morton , "=?utf-8:iso-8859-1?B?UGF3ZcWC?= Staszewski" , Jesper Dangaard Brouer , Eric Dumazet , Tariq Toukan , Ilias Apalodimas , Yoel Caspersen , Saeed Mahameed , Michal Hocko , Vlastimil Babka , Dave Hansen On Mon, Nov 05, 2018 at 04:58:19PM +0800, Aaron Lu wrote: > page_frag_free() calls __free_pages_ok() to free the page back to > Buddy. This is OK for high order page, but for order-0 pages, it > misses the optimization opportunity of using Per-Cpu-Pages and can > cause zone lock contention when called frequently. > > [1]: https://www.spinics.net/lists/netdev/msg531362.html > [2]: https://www.spinics.net/lists/netdev/msg531421.html > [3]: https://www.spinics.net/lists/netdev/msg531556.html > Reported-by: PaweA? Staszewski > Analysed-by: Jesper Dangaard Brouer > Signed-off-by: Aaron Lu Well spotted, Acked-by: Mel Gorman -- Mel Gorman SUSE Labs