From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail1.bemta23.messagelabs.com (mail1.bemta23.messagelabs.com [67.219.246.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id C440F21B02845 for ; Tue, 24 Jul 2018 07:28:43 -0700 (PDT) From: Huaisheng HS1 Ye Subject: RE: [External] Re: [PATCH 3/5] s390, dcssblk: Allow a NULL-kaddr to ->direct_access() Date: Tue, 24 Jul 2018 14:28:23 +0000 Message-ID: References: <20180724084510.6104-1-yehs2007@zoho.com> <20180724084510.6104-4-yehs2007@zoho.com> <192a9dac-921f-e222-3a7d-32d43679cd12@de.ibm.com> <814b615b-fc5d-627a-a11e-c54796b1b08d@de.ibm.com> In-Reply-To: <814b615b-fc5d-627a-a11e-c54796b1b08d@de.ibm.com> Content-Language: zh-CN MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Christian Borntraeger Cc: "axboe@kernel.dk" , "linux-s390@vger.kernel.org" , "linux-nvdimm@lists.01.org" , NingTing Cheng , "linux-fsdevel@vger.kernel.org" , "heiko.carstens@de.ibm.com" , "linux-kernel@vger.kernel.org" , "willy@infradead.org" , "bart.vanassche@wdc.com" , "viro@zeniv.linux.org.uk" , "gregkh@linuxfoundation.org" , "schwidefsky@de.ibm.com" , "jack@suse.cz" List-ID: From: Christian Borntraeger Sent: Tuesday, July 24, 2018 7:16 PM > >> So you are trading of a load + add (dev_info->start should be cache hot) against a > >> compare+branch . Not sure that this is always a win. > > > > Hmm...the calculation process of pfn is more complicated than kaddr. I think you agree to > check pfn but not sure kaddr, right? > > From the logical consistency of code, I think it shall be better to give pfn and kaddr similar > treatment. > > Reading it again, its more that I do not like the patch description. It reads > like an optimization, (and I think it is not) but it should rather read more > like "with an upcoming change kaddr can be NULL" or so. Thanks for suggestion, I will reword the patch description during next submission. Does the patch itself need to be modified? If has, any suggestion is welcome. Cheers, Huaisheng Ye _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm