From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ross Zwisler Subject: Re: [PATCH v11 54/63] dax: Hash on XArray instead of mapping Date: Tue, 22 May 2018 15:38:22 -0600 Message-ID: <20180522213822.GA12733@linux.intel.com> References: <20180414141316.7167-1-willy@infradead.org> <20180414141316.7167-55-willy@infradead.org> <20180521044756.GD27043@linux.intel.com> <20180521102524.GB20878@bombadil.infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=In-Reply-To:Content-Type:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=pQUSoWZvCaabNYbhhgx7hzhqZD9W75jILp9x/veQ0lI=; b=P2Ao1WGh5zBeRTb3pMcDUSFhqh l3qiaAHZdcUV2LzOhLRTnFsZ7aOFLPvgUJClaXYZD4nj67OMzyEb8a9rGmybf4RHUbY+ROeanxSe0 WmRoSOAcQKqt18JwhQMtSVZT5cDxAwCTPEYesn+UUU6YzgoTgOzKSTsW32TrzJdHTQCA=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To :From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=pQUSoWZvCaabNYbhhgx7hzhqZD9W75jILp9x/veQ0lI=; b=GLZZ0/Z1OP7XzPcogG9uD8i3SB Dvqxdiy/TEcXRbUp4DMNlBZ4RS3fQYUtuPakYEox5rBZrEPtNjlcvYTCPjie6rYVBHzCq0tvsKAli XMY8IFbYhqYaDrTXtNEyCDsks2R7vb4VeSwhUULxwaLWmMYtR8L1WcUY4ZaT1UN1gUrA=; Content-Disposition: inline In-Reply-To: <20180521102524.GB20878@bombadil.infradead.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Matthew Wilcox Cc: linux-nilfs@vger.kernel.org, Jan Kara , Jeff Layton , Matthew Wilcox , James Simmons , Jaegeuk Kim , Andreas Dilger , Nicholas Piggin , linux-f2fs-devel@lists.sourceforge.net, Oleg Drokin , linux-mm@kvack.org, Ryusuke Konishi , linux-fsdevel@vger.kernel.org, Lukas Czerner , Ross Zwisler , Christoph Hellwig , Goldwyn Rodrigues , Mike Kravetz On Mon, May 21, 2018 at 03:25:24AM -0700, Matthew Wilcox wrote: > On Sun, May 20, 2018 at 10:47:56PM -0600, Ross Zwisler wrote: > > On Sat, Apr 14, 2018 at 07:13:07AM -0700, Matthew Wilcox wrote: > > > From: Matthew Wilcox > > > > > > Since the XArray is embedded in the struct address_space, this contains > > > exactly as much entropy as the address of the mapping. > > > > I agree that they both have the same amount of entropy, but what's the > > benefit? It doesn't seem like this changes any behavior, fixes any bugs or > > makes things any simpler? > > This is a preparatory patch for some of the changes later in the series. > It has no benefit in and of itself; the benefit comes later when we > switch from dax_wake_mapping_entry() to dax_wake_entry(): > > static void dax_wake_entry(struct xa_state *xas, bool wake_all) > > This switch could be left until the end; I can introduce dax_wake_entry() > without this change: > > +static void dax_wake_entry(struct xa_state *xas, bool wake_all) > +{ > + struct address_space *mapping = container_of(xas->xa, > + struct address_space, i_pages); > + return dax_wake_mapping_entry_waiter(mapping, xas->xa_index, NULL, > + wake_all); > +} > > and then cut everybody over in the final step. > > Or I can just explain in the changelog that it's a preparatory step. Sure, just a note in the changelog saying that it's a preparatory step would be good enough for me. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot