From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 02/11] blkcg: __blkg_lookup_create() doesn't have to fail on radix tree preload failure Date: Fri, 27 Apr 2012 07:47:09 -0700 Message-ID: <20120427144709.GJ27486@google.com> References: <1335477561-11131-1-git-send-email-tj@kernel.org> <1335477561-11131-3-git-send-email-tj@kernel.org> <20120427144258.GI10579@redhat.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=owJaPlB+EXhnkqEwCOj9lo9yxoinTXlaT1jhl5xyYGM=; b=j2b30b9V/Q2bX2wwgZs8fre9yRJgV2BW7MWRR8EoEn6Etf74mq4htsy4e8htLyducv 7WSz8KMTkCp7sxgbj/UPRJkqtgRN8s6XwpdPRf2Uk7HdBkM4nQokGHQRefLIatB/VcrB Yg7WsBLM3Q7T5cDnTM0ZcOf5dqD65llR6987p/fhgDCSeM2xzgwzB3alfuwwEY8vwpAh Ee28WzZfWyKmSJelREQL58UdbwcvfXfVAzZDr6PFcNUUSH8cV9MIq9850yCSSO1xv+KZ MOkB2ainL+Atr5xl/x9QmEh8WCyl726TeoLLbFj0NDZVlutt/9Uq973udutxqqFXiLwO GLrw== Content-Disposition: inline In-Reply-To: <20120427144258.GI10579-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Vivek Goyal Cc: axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, ctalbott-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, rni-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, fengguang.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, hughd-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org Hello, On Fri, Apr 27, 2012 at 10:42:58AM -0400, Vivek Goyal wrote: > On Thu, Apr 26, 2012 at 02:59:12PM -0700, Tejun Heo wrote: > > __blkg_lookup_create() currently fails if radix_tree_preload() fails; > > however, preload failrue doesn't imply insertion failure. Don't fail > > __blkg_lookup_create() on preload failure. > > > > If we are going to try the insertion anyway irrespective of the fact > whether preload succeeded or not, they why call radix_tree_preload() > at all? How does that help? Hmmm... it seems I originally misread radix_tree_node_alloc() - I thought it didn't go through kmem_cache_alloc() if gfp_mask didn't contain __GFP_WAIT. If we don't use more permissible GFP flag during preloading there's no point in preloading. Will drop it. Thanks. -- tejun