From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f200.google.com (mail-io0-f200.google.com [209.85.223.200]) by kanga.kvack.org (Postfix) with ESMTP id 93FFD280244 for ; Thu, 4 Jan 2018 15:36:26 -0500 (EST) Received: by mail-io0-f200.google.com with SMTP id i67so2782767ioe.4 for ; Thu, 04 Jan 2018 12:36:26 -0800 (PST) Received: from aserp2130.oracle.com (aserp2130.oracle.com. [141.146.126.79]) by mx.google.com with ESMTPS id u20si3218668ioi.209.2018.01.04.12.36.25 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Jan 2018 12:36:25 -0800 (PST) Subject: Re: [PATCH 1/2] Move kfree_call_rcu() to slab_common.c References: <1514923898-2495-1-git-send-email-rao.shoaib@oracle.com> <20180102222341.GB20405@bombadil.infradead.org> <3be609d4-800e-a89e-f885-7e0f5d288862@oracle.com> <20180104013807.GA31392@tardis> From: Rao Shoaib Message-ID: Date: Thu, 4 Jan 2018 12:35:55 -0800 MIME-Version: 1.0 In-Reply-To: <20180104013807.GA31392@tardis> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: Boqun Feng Cc: Matthew Wilcox , linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com, brouer@redhat.com, linux-mm@kvack.org Hi Boqun, Thanks a lot for all your guidance and for catching the cut and paster error. Please see inline. On 01/03/2018 05:38 PM, Boqun Feng wrote: > > But you introduced a bug here, you should use rcu_state_p instead of > &rcu_sched_state as the third parameter for __call_rcu(). > > Please re-read: > > https://marc.info/?l=linux-mm&m=151390529209639 > > , and there are other comments, which you still haven't resolved in this > version. You may want to write a better commit log to explain the > reasons of each modifcation and fix bugs or typos in your previous > version. That's how review process works ;-) > > Regards, > Boqun > This is definitely a serious error. Thanks for catching this. As far as your previous comments are concerned, only the following one has not been addressed. Can you please elaborate as I do not understand the comment. The code was expanded because the new macro expansion check fails. Based on Matthew Wilcox's comment I have reverted rcu_head_name back to rcu_head. > +#define kfree_rcu(ptr, rcu_head_name) \ > + do { \ > + typeof(ptr) __ptr = ptr; \ > + unsigned long __off = offsetof(typeof(*(__ptr)), \ > + rcu_head_name); \ > + struct rcu_head *__rptr = (void *)__ptr + __off; \ > + __kfree_rcu(__rptr, __off); \ > + } while (0) why do you want to open code this? Does the following text for the commit log looks better. kfree_rcu() should use the new kfree_bulk() interface for freeing rcu structures The newly implemented kfree_bulk() interfaces are more efficient, using the interfaces for freeing rcu structures has shown performance improvements in synthetic benchmarks that allocate and free rcu structures at a high rate. Shoaib -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org