From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9BACDC43381 for ; Mon, 18 Mar 2019 13:08:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A63920857 for ; Mon, 18 Mar 2019 13:08:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552914481; bh=VvjPakAEsxliX9jhpCdH/sMBrHXwQ4lA6TROjt4TWRc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=mWiHjGU9llDVeF01GV8cMkeudqiE4ebRpxMipoCA0S89kXkamjSUz6g0mqfV+89uu DjSLG+VWO+n1dtTzbMBVwJ6/nNZC9rTCksVTDWpSiqDj1mkfuJA7HmDvac4/ByN23a jEFwLVJoBENP+0arIi+H6WksG5HDlV1B0HGl0e50= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727141AbfCRNIA (ORCPT ); Mon, 18 Mar 2019 09:08:00 -0400 Received: from mx2.suse.de ([195.135.220.15]:38468 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725973AbfCRNH7 (ORCPT ); Mon, 18 Mar 2019 09:07:59 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 92E7DAE07; Mon, 18 Mar 2019 13:07:58 +0000 (UTC) Date: Mon, 18 Mar 2019 14:07:57 +0100 From: Michal Hocko To: Pankaj Suryawanshi Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "minchan@kernel.org" , Kirill Tkhai Subject: Re: mm/cma.c: High latency for cma allocation Message-ID: <20190318130757.GG8924@dhcp22.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 18-03-19 12:58:28, Pankaj Suryawanshi wrote: > Hello, > > I am facing issue of high latency in CMA allocation of large size buffer. > > I am frequently allocating/deallocation CMA memory, latency of allocation is very high. > > Below are the stat for allocation/deallocation latency issue. > > (390100 kB), latency 29997 us > (390100 kB), latency 22957 us > (390100 kB), latency 25735 us > (390100 kB), latency 12736 us > (390100 kB), latency 26009 us > (390100 kB), latency 18058 us > (390100 kB), latency 27997 us > (16 kB), latency 560 us > (256 kB), latency 280 us > (4 kB), latency 311 us > > I am using kernel 4.14.65 with android pie(9.0). > > Is there any workaround or solution for this(cma_alloc latency) issue ? Do you have any more detailed information on where the time is spent? E.g. migration tracepoints? -- Michal Hocko SUSE Labs