From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f198.google.com (mail-io0-f198.google.com [209.85.223.198]) by kanga.kvack.org (Postfix) with ESMTP id 6524F280244 for ; Thu, 4 Jan 2018 16:33:09 -0500 (EST) Received: by mail-io0-f198.google.com with SMTP id d17so2822138ioc.23 for ; Thu, 04 Jan 2018 13:33:09 -0800 (PST) Received: from aserp2120.oracle.com (aserp2120.oracle.com. [141.146.126.78]) by mx.google.com with ESMTPS id c17si3419438itc.33.2018.01.04.13.33.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 04 Jan 2018 13:33:07 -0800 (PST) Subject: Re: [PATCH 1/2] Move kfree_call_rcu() to slab_common.c From: Rao Shoaib 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> Message-ID: <64ca3929-4044-9393-a6ca-70c0a2589a35@oracle.com> Date: Thu, 4 Jan 2018 13:27:49 -0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit 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 On 01/04/2018 12:35 PM, Rao Shoaib wrote: > 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. It turns out I did not remember the real reason for the change. With the macro rewritten, using rcu_head as a macro argument does not work because it conflicts with the name of the type 'struct rcu_head' used in the macro. I have renamed the macro argument to rcu_name. Shoaib > >> +#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 -- 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