From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760870AbYBKVxa (ORCPT ); Mon, 11 Feb 2008 16:53:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760076AbYBKVxR (ORCPT ); Mon, 11 Feb 2008 16:53:17 -0500 Received: from mga05.intel.com ([192.55.52.89]:54544 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1759990AbYBKVxQ (ORCPT ); Mon, 11 Feb 2008 16:53:16 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.25,335,1199692800"; d="scan'208";a="516806658" Date: Mon, 11 Feb 2008 13:56:51 -0800 From: mark gross To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: iova RB tree setup tweak. Message-ID: <20080211215651.GA24412@linux.intel.com> Reply-To: mgross@linux.intel.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following patch merges two functions into one allowing for a 3% reduction in overhead in locating, allocating and inserting pages for use in IOMMU operations. Its a bit of a eye-crosser so I welcome any RB-tree / MM experts to take a look. It works by re-using some of the information gathered in the search for the pages to use in setting up the IOTLB's in the insertion of the iova structure into the RB tree. --mgross Singed-off-by: Index: linux-2.6.24-mm1/drivers/pci/iova.c =================================================================== --- linux-2.6.24-mm1.orig/drivers/pci/iova.c 2008-02-07 11:05:44.000000000 -0800 +++ linux-2.6.24-mm1/drivers/pci/iova.c 2008-02-07 13:05:03.000000000 -0800 @@ -72,20 +72,25 @@ return pad_size; } -static int __alloc_iova_range(struct iova_domain *iovad, unsigned long size, - unsigned long limit_pfn, struct iova *new, bool size_aligned) +static int __alloc_and_insert_iova_range(struct iova_domain *iovad, + unsigned long size, unsigned long limit_pfn, + struct iova *new, bool size_aligned) { - struct rb_node *curr = NULL; + struct rb_node *prev, *curr = NULL; unsigned long flags; unsigned long saved_pfn; unsigned int pad_size = 0; /* Walk the tree backwards */ spin_lock_irqsave(&iovad->iova_rbtree_lock, flags); saved_pfn = limit_pfn; curr = __get_cached_rbnode(iovad, &limit_pfn); + prev = curr; while (curr) { struct iova *curr_iova = container_of(curr, struct iova, node); + if (limit_pfn < curr_iova->pfn_lo) goto move_left; else if (limit_pfn < curr_iova->pfn_hi) @@ -99,6 +104,7 @@ adjust_limit_pfn: limit_pfn = curr_iova->pfn_lo - 1; move_left: + prev = curr; curr = rb_prev(curr); } @@ -115,7 +121,33 @@ new->pfn_lo = limit_pfn - (size + pad_size) + 1; new->pfn_hi = new->pfn_lo + size - 1; + /* Insert the new_iova into domain rbtree by holding writer lock */ + /* Add new node and rebalance tree. */ + { + struct rb_node **entry = &((prev)), *parent = NULL; + /* Figure out where to put new node */ + while (*entry) { + struct iova *this = container_of(*entry, + struct iova, node); + parent = *entry; + + if (new->pfn_lo < this->pfn_lo) + entry = &((*entry)->rb_left); + else if (new->pfn_lo > this->pfn_lo) + entry = &((*entry)->rb_right); + else + BUG(); /* this should not happen */ + } + + /* Add new node and rebalance tree. */ + rb_link_node(&new->node, parent, entry); + rb_insert_color(&new->node, &iovad->rbroot); + } + __cached_rbnode_insert_update(iovad, saved_pfn, new); + spin_unlock_irqrestore(&iovad->iova_rbtree_lock, flags); + + return 0; } @@ -171,23 +203,15 @@ size = __roundup_pow_of_two(size); spin_lock_irqsave(&iovad->iova_alloc_lock, flags); - ret = __alloc_iova_range(iovad, size, limit_pfn, new_iova, - size_aligned); + ret = __alloc_and_insert_iova_range(iovad, size, limit_pfn, + new_iova, size_aligned); + spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); if (ret) { - spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); free_iova_mem(new_iova); return NULL; } - /* Insert the new_iova into domain rbtree by holding writer lock */ - spin_lock(&iovad->iova_rbtree_lock); - iova_insert_rbtree(&iovad->rbroot, new_iova); - __cached_rbnode_insert_update(iovad, limit_pfn, new_iova); - spin_unlock(&iovad->iova_rbtree_lock); - - spin_unlock_irqrestore(&iovad->iova_alloc_lock, flags); - return new_iova; }