From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (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 658DE203BBBB0 for ; Mon, 7 May 2018 20:10:06 -0700 (PDT) Date: Mon, 7 May 2018 20:09:59 -0700 From: Matthew Wilcox Subject: Re: [External] Re: [RFC PATCH v1 0/6] use mm to manage NVDIMM (pmem) zone Message-ID: <20180508030959.GB16338@bombadil.infradead.org> References: <1525704627-30114-1-git-send-email-yehs1@lenovo.com> <20180507184622.GB12361@bombadil.infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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: Huaisheng HS1 Ye Cc: Sasha Levin , Michal Hocko , linux-nvdimm , Tetsuo Handa , NingTing Cheng , Linux Kernel Mailing List , "pasha.tatashin@oracle.com" , Linux MM , Dave Hansen , Johannes Weiner , "colyli@suse.de" , Mel Gorman , Andrew Morton , Vlastimil Babka List-ID: On Tue, May 08, 2018 at 02:59:40AM +0000, Huaisheng HS1 Ye wrote: > Currently in our mind, an ideal use scenario is that, we put all page caches to > zone_nvm, without any doubt, page cache is an efficient and common cache > implement, but it has a disadvantage that all dirty data within it would has risk > to be missed by power failure or system crash. If we put all page caches to NVDIMMs, > all dirty data will be safe. That's a common misconception. Some dirty data will still be in the CPU caches. Are you planning on building servers which have enough capacitance to allow the CPU to flush all dirty data from LLC to NV-DIMM? Then there's the problem of reconnecting the page cache (which is pointed to by ephemeral data structures like inodes and dentries) to the new inodes. And then you have to convince customers that what you're doing is safe enough for them to trust it ;-) _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm