From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763287AbYBLPah (ORCPT ); Tue, 12 Feb 2008 10:30:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763118AbYBLPaB (ORCPT ); Tue, 12 Feb 2008 10:30:01 -0500 Received: from mga10.intel.com ([192.55.52.92]:22278 "EHLO fmsmga102.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1763090AbYBLP37 (ORCPT ); Tue, 12 Feb 2008 10:29:59 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.25,341,1199692800"; d="scan'208";a="517242236" Date: Tue, 12 Feb 2008 07:33:54 -0800 From: mark gross To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Greg KH Subject: Re: iova RB tree setup tweak. Message-ID: <20080212153354.GA27490@linux.intel.com> Reply-To: mgross@linux.intel.com References: <20080211215651.GA24412@linux.intel.com> <20080211142946.379455af.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080211142946.379455af.akpm@linux-foundation.org> 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 On Mon, Feb 11, 2008 at 02:29:46PM -0800, Andrew Morton wrote: > On Mon, 11 Feb 2008 13:56:51 -0800 > mark gross wrote: > > > 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. > > > > I guess this is a PCI patch hence I'd be tagging is as > to-be-merged-via-greg's-pci-tree. > > > > > Singed-off-by: > > > > ow, that musta hurt. Not at first but ever since I posted the patch its been a bit. > > > > > 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 @@ > > For some reason patch(1) claims that the patch is corrupted at this line. > My bad. Try the following: --mgross Signed-off-by : fa-la-la 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 2008-02-12 07:12:47.000000000 -0800 @@ -72,10 +72,11 @@ 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; @@ -84,8 +85,10 @@ 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 +102,7 @@ adjust_limit_pfn: limit_pfn = curr_iova->pfn_lo - 1; move_left: + prev = curr; curr = rb_prev(curr); } @@ -115,7 +119,33 @@ 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 +201,15 @@ 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; }