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[209.132.180.67]) by mx.google.com with ESMTP id c136si5061284pfc.141.2018.11.27.13.03.49; Tue, 27 Nov 2018 13:04:06 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@toxicpanda-com.20150623.gappssmtp.com header.s=20150623 header.b=s6TA9BR+; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726570AbeK1IAq (ORCPT + 99 others); Wed, 28 Nov 2018 03:00:46 -0500 Received: from mail-qk1-f196.google.com ([209.85.222.196]:44709 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726234AbeK1IAq (ORCPT ); Wed, 28 Nov 2018 03:00:46 -0500 Received: by mail-qk1-f196.google.com with SMTP id n12so15473118qkh.11 for ; Tue, 27 Nov 2018 13:01:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=toxicpanda-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=2+oB3NQ6DcHGeIHckr9cxaNYbTfbF5HSphI11S9KWTQ=; b=s6TA9BR+Y6w/5h1lwrPObaaUUawuQqf64/Sa+x+v3JxRRzJ57egayvruUwD9bjd+Sv q52LBGdh9SNQPlHfTlKYm6TWbbJqF/smr6Ea9KRseqDzubjyjQ1sTanXW1BHYoOTuU5a 3NZ8/eJE4EYKKA+LZUO4bnLBGQ1PCQDzG4/7UTKoQfoGKdM61nGItxtYEjl27flovFMS bPdZIhr4xB553ypzY21QJ6OAAn8rjTUX51v1ZGKGQi4Ingk2T74IA3yrxYbNeKZC31+F nNI3Ju76jqgUvDTysHyezpw4/DQuY6vCU2/AeUFqOTy2zTvTMQxXsSJuoUqJVc/CsX1G HQ6Q== 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:user-agent; bh=2+oB3NQ6DcHGeIHckr9cxaNYbTfbF5HSphI11S9KWTQ=; b=VMtWYd/3oXTJzeGQA6YRcMUc6rnPycy8XdtC/vn3nxpzF1+leuwuV9lfNBdZY4xi7A pEaYC4Yku0VSOEzdADqzmrRSNjreHfQiQ2LpH9Q9WaGNsTu2BHyLIdwBf+CVNHhDrP8d PwpXXFXNINcxd56L8oS+n+KMidsvLu6jnSfJVQWf8T8Bar7SsqtqyFPI1QmIHdJ1j6Hp 3SCkejGH6Zdz3MZ8pjpv1p7tnauNBUTMGzxUqxk6tu7IgEy4RdFMk/hsXRlcHAmTpy8X z+8ZLnCS/dzmbZ0Lze6/luV8oWV7ALa5A+fPDmfTKOT+dxy3b45Ham5ZYpj16I1kjeJH 877w== X-Gm-Message-State: AA+aEWY1+H/PbwPv29I3EqJxBc+qDR5U6lTTiC30tRFmODf2dll2Pugp Fq/dt1X7NkmRLgeDvvgvul25oA== X-Received: by 2002:a37:1b46:: with SMTP id b67mr31694458qkb.144.1543352495953; Tue, 27 Nov 2018 13:01:35 -0800 (PST) Received: from localhost ([2620:10d:c091:180::1:4c40]) by smtp.gmail.com with ESMTPSA id u16sm3672633qkg.14.2018.11.27.13.01.34 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 27 Nov 2018 13:01:35 -0800 (PST) Date: Tue, 27 Nov 2018 16:01:33 -0500 From: Josef Bacik To: Dennis Zhou Cc: Jens Axboe , Tejun Heo , Johannes Weiner , Josef Bacik , kernel-team@fb.com, linux-block@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 03/13] blkcg: convert blkg_lookup_create() to find closest blkg Message-ID: <20181127210131.7cdgku7cmixxwdbc@macbook-pro-91.dhcp.thefacebook.com> References: <20181126211946.77067-1-dennis@kernel.org> <20181126211946.77067-4-dennis@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181126211946.77067-4-dennis@kernel.org> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 26, 2018 at 04:19:36PM -0500, Dennis Zhou wrote: > There are several scenarios where blkg_lookup_create() can fail such as > the blkcg dying, request_queue is dying, or simply being OOM. Most > handle this by simply falling back to the q->root_blkg and calling it a > day. > > This patch implements the notion of closest blkg. During > blkg_lookup_create(), if it fails to create, return the closest blkg > found or the q->root_blkg. blkg_try_get_closest() is introduced and used > during association so a bio is always attached to a blkg. > > Signed-off-by: Dennis Zhou > Acked-by: Tejun Heo Reviewed-by: Josef Bacik Thanks, Josef