From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id A77CA4404A3 for ; Fri, 16 Jun 2017 15:45:42 -0400 (EDT) Received: by mail-pg0-f72.google.com with SMTP id b13so51150961pgn.4 for ; Fri, 16 Jun 2017 12:45:42 -0700 (PDT) Received: from mga06.intel.com (mga06.intel.com. [134.134.136.31]) by mx.google.com with ESMTPS id q125si2588026pgq.187.2017.06.16.12.45.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Jun 2017 12:45:42 -0700 (PDT) Date: Fri, 16 Jun 2017 13:45:40 -0600 From: Ross Zwisler Subject: Re: [PATCH v2 3/3] dax: use common 4k zero page for dax mmap reads Message-ID: <20170616194540.GB20742@linux.intel.com> References: <20170614172211.19820-1-ross.zwisler@linux.intel.com> <20170614172211.19820-4-ross.zwisler@linux.intel.com> <20170615145856.GO1764@quack2.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170615145856.GO1764@quack2.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: Ross Zwisler , Andrew Morton , linux-kernel@vger.kernel.org, "Darrick J. Wong" , Theodore Ts'o , Alexander Viro , Andreas Dilger , Christoph Hellwig , Dan Williams , Dave Hansen , Ingo Molnar , Jonathan Corbet , Matthew Wilcox , Steven Rostedt , linux-doc@vger.kernel.org, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-nvdimm@lists.01.org, linux-xfs@vger.kernel.org On Thu, Jun 15, 2017 at 04:58:56PM +0200, Jan Kara wrote: > On Wed 14-06-17 11:22:11, Ross Zwisler wrote: > > @@ -216,17 +217,6 @@ static void dax_unlock_mapping_entry(struct address_space *mapping, > > dax_wake_mapping_entry_waiter(mapping, index, entry, false); > > } > > > > -static void put_locked_mapping_entry(struct address_space *mapping, > > - pgoff_t index, void *entry) > > -{ > > - if (!radix_tree_exceptional_entry(entry)) { > > - unlock_page(entry); > > - put_page(entry); > > - } else { > > - dax_unlock_mapping_entry(mapping, index); > > - } > > -} > > - > > The naming becomes asymetric with this. So I'd prefer keeping > put_locked_mapping_entry() as a trivial wrapper around > dax_unlock_mapping_entry() unless we can craft more sensible naming / API > for entry grabbing (and that would be a separate patch anyway). Sure, that works for me. I'll fix for v3. > > -static int dax_load_hole(struct address_space *mapping, void **entry, > > +static int dax_load_hole(struct address_space *mapping, void *entry, > > struct vm_fault *vmf) > > { > > struct inode *inode = mapping->host; > > - struct page *page; > > - int ret; > > - > > - /* Hole page already exists? Return it... */ > > - if (!radix_tree_exceptional_entry(*entry)) { > > - page = *entry; > > - goto finish_fault; > > - } > > + unsigned long vaddr = vmf->address; > > + int ret = VM_FAULT_NOPAGE; > > + struct page *zero_page; > > + void *entry2; > > > > - /* This will replace locked radix tree entry with a hole page */ > > - page = find_or_create_page(mapping, vmf->pgoff, > > - vmf->gfp_mask | __GFP_ZERO); > > With this gone, you can also remove the special DAX handling from > mm/filemap.c: page_cache_tree_insert() and remove from dax.h > dax_wake_mapping_entry_waiter(), dax_radix_locked_entry() and RADIX_DAX > definitions. Yay! As a separate patch please. Oh, yay! :) Sure, I'll have this patch for v3. -- 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