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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 5CF60C433E0 for ; Tue, 9 Feb 2021 13:55:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0825164EEC for ; Tue, 9 Feb 2021 13:55:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230299AbhBINzF (ORCPT ); Tue, 9 Feb 2021 08:55:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33830 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232054AbhBINyc (ORCPT ); Tue, 9 Feb 2021 08:54:32 -0500 Received: from mail-qk1-x72d.google.com (mail-qk1-x72d.google.com [IPv6:2607:f8b0:4864:20::72d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 678F8C061794 for ; Tue, 9 Feb 2021 05:53:33 -0800 (PST) Received: by mail-qk1-x72d.google.com with SMTP id q85so5625933qke.8 for ; Tue, 09 Feb 2021 05:53:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=T8f8DDfwXSd9VRLmEP8P3umzAghI6Kqw6/qy/jeS5Qo=; b=gh04iuWWyfXXLlaV1RWSVt6ZQHHbXgL+7SqTdgohcZssGB7SFCglc2Da1zz58QYygR 9tVoLF0GKpMU5fAKOJUQeZbKmiZNBpriOh6NJ88Z8/8Oiy+02484H0DfDsD9oLpEdCJB iqbllGJHAulzwrFuz8zaWKtRoDWR91pkLeY3goABlW/bNnl7a7ucWFWFLWHoTWeFdCfi E81odK7NiX2mIG23/RyV6fotvVvwHXBJ3/Y6NQ+7HvCiAyAGmRSY3kUdW52i458n5RX4 NyglMvima/h3o9mIMHNuMfUszee7pZjUtNzI0o4O78Zz7zTTtKPysaZeIPpMxYD972RH nQ7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=T8f8DDfwXSd9VRLmEP8P3umzAghI6Kqw6/qy/jeS5Qo=; b=U0y4Dd/vXbUVq0kxG2pjGIEVHnFfziD4Jk4aMiAgfJzujfjej6KX7d3PCYD88pP6SR l4Pue4PJpmpbZWcfHsvJkcT0PduY+u/+ZRIWH/iCK7MhmkOompLraQT2Fnu5SXcEUrXI TFfJ+/uxXgSuh4TqtTRak4w0V9VjW5W4BEoW0rnNqGgphGul7ueecp3lOcawnBnLPM4T vC33+Oe/iWEoqJ3o3dbB+3IijAHnQXwCjt5monnE6/SG2/FBw84vUWpLNOCKmEM5kIKn SxuXK3JsFzIpCxkLQO4ErWHYTXX6/lRNYC44a6D0NHIavXyNTJl7VjP0+eaCH5PCMAKU utvw== X-Gm-Message-State: AOAM532zR+zbgy67Pj66mvLHkfAJcUwlzm+gp0dQi7bhtcQJRWwt9IEo GDLeipY8cruX7gDbfiIb69pNOw== X-Google-Smtp-Source: ABdhPJx3et279cgNvk+uqR894IQLoOIQFoSZDGEjQvDKhVHg09126LSd7Y8VSphbQdCDRlOdHVR86w== X-Received: by 2002:ae9:e80e:: with SMTP id a14mr11633708qkg.103.1612878812715; Tue, 09 Feb 2021 05:53:32 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-162-115-133.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.115.133]) by smtp.gmail.com with ESMTPSA id d16sm17820271qka.44.2021.02.09.05.53.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Feb 2021 05:53:32 -0800 (PST) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1l9TSN-005RZu-ON; Tue, 09 Feb 2021 09:53:31 -0400 Date: Tue, 9 Feb 2021 09:53:31 -0400 From: Jason Gunthorpe To: "Song Bao Hua (Barry Song)" Cc: David Hildenbrand , "Wangzhou (B)" , "linux-kernel@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-mm@kvack.org" , "linux-arm-kernel@lists.infradead.org" , "linux-api@vger.kernel.org" , Andrew Morton , Alexander Viro , "gregkh@linuxfoundation.org" , "kevin.tian@intel.com" , "jean-philippe@linaro.org" , "eric.auger@redhat.com" , "Liguozhu (Kenneth)" , "zhangfei.gao@linaro.org" , "chensihang (A)" Subject: Re: [RFC PATCH v3 1/2] mempinfd: Add new syscall to provide memory pin Message-ID: <20210209135331.GF4718@ziepe.ca> References: <1612685884-19514-1-git-send-email-wangzhou1@hisilicon.com> <1612685884-19514-2-git-send-email-wangzhou1@hisilicon.com> <20210208183348.GV4718@ziepe.ca> <0dca000a6cd34d8183062466ba7d6eaf@hisilicon.com> <20210208213023.GZ4718@ziepe.ca> <0868d209d7424942a46d1238674cf75d@hisilicon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0868d209d7424942a46d1238674cf75d@hisilicon.com> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Tue, Feb 09, 2021 at 03:01:42AM +0000, Song Bao Hua (Barry Song) wrote: > On the other hand, wouldn't it be the benefit of hardware accelerators > to have a lower and more stable latency zip/encryption than CPU? No, I don't think so. If this is an important problem then it should apply equally to CPU and IO jitter. Honestly I find the idea that occasional migration jitters CPU and DMA to not be very compelling. Such specialized applications should allocate special pages to avoid this, not adding an API to be able to lock down any page Jason