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_HELO_NONE,SPF_PASS, USER_AGENT_MUTT autolearn=unavailable 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 8FE44C43613 for ; Thu, 20 Jun 2019 17:02:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 652A120675 for ; Thu, 20 Jun 2019 17:02:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561050177; bh=lIp8l9DK015GOcCxOE8CHeNJkBtCSUuS80+Oe7INHH0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=X8XBIqrwxC5zrh4PdCkwNVWEqIetG2qmLOiLCSpGy2F7cCPWKKOk/y60qhN429ejf vXszyWIXbR91qI5mRAQ1TMx+aDHjv6VpUb8W4IJEkzGZCTtc260Yy8gKtAeQ38UBPP LJvnLt6hWb6XZjaii+8m8dZne9xUKd+mf5E9CHCU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726838AbfFTRCy (ORCPT ); Thu, 20 Jun 2019 13:02:54 -0400 Received: from mail-pf1-f193.google.com ([209.85.210.193]:46475 "EHLO mail-pf1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726530AbfFTRCx (ORCPT ); Thu, 20 Jun 2019 13:02:53 -0400 Received: by mail-pf1-f193.google.com with SMTP id 81so1992253pfy.13; Thu, 20 Jun 2019 10:02:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=8wf4cUw4MBLQ5ZMRZPNnEwMB/4TzHc3tHqQ0sOQp8Os=; b=Wg6NBK6vKlCLiPsPaXNE5QvvdM2CnFaRmcfdeCBn9IjI1jcuHtXo7vm10THbVibgnu u0U7RfwHLhckYVSyanRghxO5KKgFrrx1Tx4JOIjTIzPy1Od9dftVLvCn9tWRZ1vUSSXU d+3feEShEKF3XAyfMZcDewHa0x/55pg6P0pN0kSQShr+btUn26moy4nPnGaKIoul6YM/ Pr7GbJHYFwpcwYnHcejjSWyjTgcRVINTrfM+oS3oYJ7kIpqZStAf0KLTrI3+NwphEEyA 5vV47bnRpY8qlF/5PnVI9gwXpelTqwQ0RNcBW8OiyK6J3jOOUcERQ6pfuTPhiI5JtpkL dzag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=8wf4cUw4MBLQ5ZMRZPNnEwMB/4TzHc3tHqQ0sOQp8Os=; b=EGGdUTVV4rNbNCSm13F0Ykg4l5k1/ltY/+3LhvFDm+AZ+ndEKypiAdOTuyufOnkwnx /b0Bgt+dUw1naLiA/HLZjhpSRkfyEcrw4nNlGBbeuxOAf8iJzySK24ETOF9RH2Y/HvEN GnjxPwAGQIz0fh+7wJnY5qiJ6vzQ8ZGdKH8YhKQqoORYXl5rA/jxL+mJhoZ+1A3fikcq Iys1cvUGmIwXbnEHr+ZkzIgB4geiJfbIlgTgLaqZe6obVOb+CHvyfSafq6rVsvJJq3uX jb40JjYCRNvA0GyUxo+JamDCQggv5rSC0fPPrt+lQ8fNDkd9eL5+xff04znr77MKkerz liLQ== X-Gm-Message-State: APjAAAV2TFVkq6iusIwF7AZZ4GzK8CX3GGxUwPWAnHiQQw1oy5pa64RR L6Paui0G/AT5fk1udigv8h2ED2K1zI4= X-Google-Smtp-Source: APXvYqzo7LjGo49CmlMqmYF7gjPoklzF78RZuEScWmDOaqfh7XoF3z//V+4KuxJQBWcA7NOcTxhIvg== X-Received: by 2002:aa7:8157:: with SMTP id d23mr131848775pfn.92.1561050172819; Thu, 20 Jun 2019 10:02:52 -0700 (PDT) Received: from localhost ([2620:10d:c091:500::3:8402]) by smtp.gmail.com with ESMTPSA id p27sm27462pfq.136.2019.06.20.10.02.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 20 Jun 2019 10:02:52 -0700 (PDT) Date: Thu, 20 Jun 2019 10:02:50 -0700 From: Tejun Heo To: Jan Kara Cc: dsterba@suse.com, clm@fb.com, josef@toxicpanda.com, axboe@kernel.dk, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 2/9] blkcg, writeback: Add wbc->no_wbc_acct Message-ID: <20190620170250.GL657710@devbig004.ftw2.facebook.com> References: <20190615182453.843275-1-tj@kernel.org> <20190615182453.843275-3-tj@kernel.org> <20190620152145.GL30243@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190620152145.GL30243@quack2.suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Hello, Jan. On Thu, Jun 20, 2019 at 05:21:45PM +0200, Jan Kara wrote: > I'm completely ignorant of how btrfs compressed writeback works so don't > quite understand implications of this. So does this mean that writeback to > btrfs compressed files won't be able to transition inodes from one memcg to > another? Or are you trying to say the 'wbc' used from async worker thread > is actually a dummy one and we would double-account the writeback? So, before, only the async compression workers would run through the wbc accounting code regardless of who originated the dirty pages, which is obviously wrong. After the patch, the code accounts when the dirty pages are being handed off to the compression workers and no_wbc_acct is used to suppress spurious accounting from the workers. > Anyway, AFAICS no_wbc_acct means: "IO done as a result of this wbc will not > have influence on inode memcg ownership", doesn't it? Yeap. Thanks. -- tejun