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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id j15si14325814pfi.8.2019.04.03.10.23.44 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 03 Apr 2019 10:23:44 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=WcbLykPN; spf=pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=willy@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; 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=zModaMrriE/hDDtVlXWrEVhoyZAp1FMyXnAmN/NXe0E=; b=WcbLykPNLboAU+ciI4NMLCIDe Z6anVMTST5BQ6g4ZKs+bxsg7dmx353AbIHO2bgVpKlNZZbXPkrk+WnujgQGLRQy8K3SRqyQiJRutv jkjwjTRBL4EvWM/7izzAvy3lOSaBii31BfLfeft6t9K0DhmrlT+B92H7hvxcpjrQVaqAtsF7JGi1F 5ySylFRefcmQbe8SXpN+HPk1EGwuI6qu0XgykFmEZ7OUhIWcmSkrGdgoWqYKTFEFRIZLfW1+/OO3I WaTFaUxXw7a3aMmahQg5Mxahyq627ia53RCgEOHLMocouJ2HFgeSu8HXGnPkZXOA8zR6JvNKwhQpk WKpMFrsxQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1hBjbi-000465-Iu; Wed, 03 Apr 2019 17:23:26 +0000 Date: Wed, 3 Apr 2019 10:23:26 -0700 From: Matthew Wilcox To: "Tobin C. Harding" Cc: Andrew Morton , Roman Gushchin , Alexander Viro , Christoph Hellwig , Pekka Enberg , David Rientjes , Joonsoo Kim , Christopher Lameter , Miklos Szeredi , Andreas Dilger , Waiman Long , Tycho Andersen , Theodore Ts'o , Andi Kleen , David Chinner , Nick Piggin , Rik van Riel , Hugh Dickins , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2 09/14] xarray: Implement migration function for objects Message-ID: <20190403172326.GJ22763@bombadil.infradead.org> References: <20190403042127.18755-1-tobin@kernel.org> <20190403042127.18755-10-tobin@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190403042127.18755-10-tobin@kernel.org> User-Agent: Mutt/1.9.2 (2017-12-15) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Apr 03, 2019 at 03:21:22PM +1100, Tobin C. Harding wrote: > +void xa_object_migrate(struct xa_node *node, int numa_node) > +{ > + struct xarray *xa = READ_ONCE(node->array); > + void __rcu **slot; > + struct xa_node *new_node; > + int i; > + > + /* Freed or not yet in tree then skip */ > + if (!xa || xa == XA_RCU_FREE) > + return; > + > + new_node = kmem_cache_alloc_node(radix_tree_node_cachep, > + GFP_KERNEL, numa_node); > + if (!new_node) > + return; > + > + xa_lock_irq(xa); > + > + /* Check again..... */ > + if (xa != node->array || !list_empty(&node->private_list)) { > + node = new_node; > + goto unlock; > + } > + > + memcpy(new_node, node, sizeof(struct xa_node)); > + > + /* Move pointers to new node */ > + INIT_LIST_HEAD(&new_node->private_list); Surely we can do something more clever, like ... if (xa != node->array) { ... if (list_empty(&node->private_list)) INIT_LIST_HEAD(&new_node->private_list); else list_replace(&node->private_list, &new_node->private_list); BTW, the raidx tree nodes / xa_nodes share the same slab cache; we need to finish converting all radix tree & IDR users to the XArray before this series can go in.