From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932176Ab2D0OrP (ORCPT ); Fri, 27 Apr 2012 10:47:15 -0400 Received: from mail-pz0-f51.google.com ([209.85.210.51]:60015 "EHLO mail-pz0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759969Ab2D0OrO (ORCPT ); Fri, 27 Apr 2012 10:47:14 -0400 Date: Fri, 27 Apr 2012 07:47:09 -0700 From: Tejun Heo To: Vivek Goyal Cc: axboe@kernel.dk, ctalbott@google.com, rni@google.com, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, containers@lists.linux-foundation.org, fengguang.wu@intel.com, hughd@google.com, akpm@linux-foundation.org Subject: Re: [PATCH 02/11] blkcg: __blkg_lookup_create() doesn't have to fail on radix tree preload failure 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 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120427144258.GI10579@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.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