From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f198.google.com (mail-wr0-f198.google.com [209.85.128.198]) by kanga.kvack.org (Postfix) with ESMTP id 927236B0390 for ; Tue, 28 Mar 2017 03:32:23 -0400 (EDT) Received: by mail-wr0-f198.google.com with SMTP id y77so25163998wrb.22 for ; Tue, 28 Mar 2017 00:32:23 -0700 (PDT) Received: from mail-wr0-x243.google.com (mail-wr0-x243.google.com. [2a00:1450:400c:c0c::243]) by mx.google.com with ESMTPS id e17si2430031wmf.12.2017.03.28.00.32.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Mar 2017 00:32:22 -0700 (PDT) Received: by mail-wr0-x243.google.com with SMTP id u1so19935928wra.3 for ; Tue, 28 Mar 2017 00:32:22 -0700 (PDT) Subject: Re: Page allocator order-0 optimizations merged References: <83a0e3ef-acfa-a2af-2770-b9a92bda41bb@mellanox.com> <20170322234004.kffsce4owewgpqnm@techsingularity.net> <20170323144347.1e6f29de@redhat.com> <20170323145133.twzt4f5ci26vdyut@techsingularity.net> <779ab72d-94b9-1a28-c192-377e91383b4e@gmail.com> <1fc7338f-2b36-75f7-8a7e-8321f062207b@gmail.com> <2123321554.7161128.1490599967015.JavaMail.zimbra@redhat.com> <20170327105514.1ed5b1ba@redhat.com> <20170327143947.4c237e54@redhat.com> <20170327133212.6azfgrariwocdzzd@techsingularity.net> From: Tariq Toukan Message-ID: <0873b65b-2217-005d-0b42-4af6ad66cc0f@gmail.com> Date: Tue, 28 Mar 2017 10:32:19 +0300 MIME-Version: 1.0 In-Reply-To: <20170327133212.6azfgrariwocdzzd@techsingularity.net> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman , Jesper Dangaard Brouer Cc: Pankaj Gupta , Tariq Toukan , netdev@vger.kernel.org, akpm@linux-foundation.org, linux-mm , Saeed Mahameed On 27/03/2017 4:32 PM, Mel Gorman wrote: > On Mon, Mar 27, 2017 at 02:39:47PM +0200, Jesper Dangaard Brouer wrote: >> On Mon, 27 Mar 2017 10:55:14 +0200 >> Jesper Dangaard Brouer wrote: >> >>> A possible solution, would be use the local_bh_{disable,enable} instead >>> of the {preempt_disable,enable} calls. But it is slower, using numbers >>> from [1] (19 vs 11 cycles), thus the expected cycles saving is 38-19=19. >>> >>> The problematic part of using local_bh_enable is that this adds a >>> softirq/bottom-halves rescheduling point (as it checks for pending >>> BHs). Thus, this might affects real workloads. >> >> I implemented this solution in patch below... and tested it on mlx5 at >> 50G with manually disabled driver-page-recycling. It works for me. >> >> To Mel, that do you prefer... a partial-revert or something like this? >> > > If Tariq confirms it works for him as well, this looks far safer patch Great. I will test Jesper's patch today in the afternoon. > than having a dedicate IRQ-safe queue. Your concern about the BH > scheduling point is valid but if it's proven to be a problem, there is > still the option of a partial revert. > -- 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