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=-2.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 DF84DC43603 for ; Thu, 12 Dec 2019 01:11:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B3D812173E for ; Thu, 12 Dec 2019 01:11:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="ThQkGLv0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727441AbfLLBLR (ORCPT ); Wed, 11 Dec 2019 20:11:17 -0500 Received: from mail-pj1-f65.google.com ([209.85.216.65]:36934 "EHLO mail-pj1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726791AbfLLBLR (ORCPT ); Wed, 11 Dec 2019 20:11:17 -0500 Received: by mail-pj1-f65.google.com with SMTP id ep17so293742pjb.4 for ; Wed, 11 Dec 2019 17:11:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=sGp68FxG1milZwgqvhCx5ABmHyTyp4gdvpmuwSTWMgg=; b=ThQkGLv0kWCvxCkrZE9KsADVrmz66ji1pqT0HfsZ/RBCDVO/obqW9Ao6VM6WfFYO+e QhRWx9ExsON63+CkJs1t0Z3+zSgeIS+W1ByhgR7qHL2pGjTiZz72GKJz9IaGI9ynmF16 2SDnB3EdkuQL9iRDkUTMVE3SkoMAJLSeQvzFW3SYusmZJTyeoy5ifZGT5fobtGQzxNdr TGK2FlWfxd0hl/RGoNC28QrLarZFWBQOAL+Ngu3InkGf6NZprgaKTN8RBs458W2KLcPs p44GZuDYtVgcJelf2Hc+qZ1gAul0amLCWvYmst9bKcLjuYCEcvbHYLn+n3udxG4zA1oU l/lg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=sGp68FxG1milZwgqvhCx5ABmHyTyp4gdvpmuwSTWMgg=; b=UMbQtRkw7cT5FyHomM8XWaqkvW0oXz3vNy3wxzdAKMTSjOCy+AsfEohFj9Tt5l7tWT 3PGghCb7I7NZNl4bkhOZY+4a/Tr53PJXVTm/48JIX8iqMxeJkPyeQ+Sv5pxP6WTsMZNk MQeZU3PLh9jpXJkgnVbvhBmKNcvKwHephiJTZhLil9mOxB8akTDZ9/s4deoGhWDhOAzV YF76o4jduv/VE+APeZv0ApqhAeWXyX1ccUkGFhAEBG4UezpByA/Dtz8lJ0rRLMsRQIG4 X+Bl7bHlEPdMMLyQ+sMBi7tLdZpZ6/3WiItQ2mIg2tzBeSwxp2lUNxgVtVdABZ0vwmUF dV4A== X-Gm-Message-State: APjAAAV5uS8lsIx3DoRQJU5pBf0m7A7bOZsz+I8n7EfUnUQy9xPdlXjy qCtDDObDMM7NQkIwDa1q83IrIw== X-Google-Smtp-Source: APXvYqyccbP8taY3xEoa/hOPmelOCM+2rRePZa3inYolV7y9/awTpbymwJZCjz2wKvfeJTt/iVVOiw== X-Received: by 2002:a17:90a:9bc6:: with SMTP id b6mr6962092pjw.77.1576113076415; Wed, 11 Dec 2019 17:11:16 -0800 (PST) Received: from [192.168.1.188] ([66.219.217.145]) by smtp.gmail.com with ESMTPSA id c10sm4650779pfo.135.2019.12.11.17.11.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 11 Dec 2019 17:11:15 -0800 (PST) Subject: Re: [PATCHSET v3 0/5] Support for RWF_UNCACHED To: Linus Torvalds Cc: Linux-MM , linux-fsdevel , linux-block , Matthew Wilcox , Chris Mason , Dave Chinner , Johannes Weiner References: <20191211152943.2933-1-axboe@kernel.dk> <0d4e3954-c467-30a7-5a8e-7c4180275533@kernel.dk> From: Jens Axboe Message-ID: <1c93194a-ed91-c3aa-deb5-a3394805defb@kernel.dk> Date: Wed, 11 Dec 2019 18:11:13 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 12/11/19 6:08 PM, Linus Torvalds wrote: > On Wed, Dec 11, 2019 at 3:41 PM Jens Axboe wrote: >> >> Here's what I did to reproduce: > > Gaah. I have a fairly fast ssd (but it's "consumer fast" - Samsung 970 > Pro - I'm assuming yours is a different class), but I encrypt my disk, > so I only get about 15k iops and I see kcyrptd in my profiles, not > kswapd. > > I didn't even try to worry about RWF_UNCACHED or RWF_NOACCESS, since I > wanted to see the problem. But I think that with my setup, I can't > really see it just due to my IO being slow ;( > > I do see xas_create and kswapd0, but it's 0.42%. I'm assuming it's the > very first signs of this problem, but it's certainly not all that > noticeable. 15K is likely too slow to really show an issue, I'm afraid. The 970 is no slouch, but your crypt setup will likely hamper it a lot. You don't have a non-encrypted partition on it? I always set aside a decently sized empty partition on my laptop to be able to run these kinds of things without having to resort to a test box. Latency is where it's down the most, you'll likely do better with more threads to get the IOPS up. -- Jens Axboe