From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCA54C433E0 for ; Tue, 26 May 2020 05:19:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C87F207D8 for ; Tue, 26 May 2020 05:19:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="kx1lX6Th" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726277AbgEZFTY (ORCPT ); Tue, 26 May 2020 01:19:24 -0400 Received: from mail26.static.mailgun.info ([104.130.122.26]:43804 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725773AbgEZFTY (ORCPT ); Tue, 26 May 2020 01:19:24 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1590470364; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=ohp+JgoF6ma7SmGrp8A76s29bGP0dhSRyUxWeLQkWYM=; b=kx1lX6ThjBYpYoUyXiD9LuiHo7hRlU5+dA3X+E896HEcSeO4W8JNwxteXRKJOMfGeTUwUvCC UkE/pQzfYejSLk41KQNmLMlVyWxwFWRPY0m4s7jg7J4JDFofB52aYOl+UPNOdnH2jcc/jmwv 9xzA1aczBbQH+aGyXEDDPY4W2MY= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5ecca6d1.7f4f7685bc70-smtp-out-n01; Tue, 26 May 2020 05:19:13 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 29ED9C43387; Tue, 26 May 2020 05:19:13 +0000 (UTC) Received: from [192.168.0.104] (unknown [103.248.210.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vjitta) by smtp.codeaurora.org (Postfix) with ESMTPSA id AF95FC433C6; Tue, 26 May 2020 05:19:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org AF95FC433C6 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=vjitta@codeaurora.org Subject: Re: [PATCH v2] iommu/iova: Retry from last rb tree node if iova search fails To: joro@8bytes.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Cc: robin.murphy@arm.com, ajaynumb@gmail.com, vinmenon@codeaurora.org, kernel-team@android.com References: <1589195093-17129-1-git-send-email-vjitta@codeaurora.org> From: Vijayanand Jitta Message-ID: <00e03593-cc31-4af5-470f-da717781fa9b@codeaurora.org> Date: Tue, 26 May 2020 10:48:58 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <1589195093-17129-1-git-send-email-vjitta@codeaurora.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/11/2020 4:34 PM, vjitta@codeaurora.org wrote: > From: Vijayanand Jitta > > When ever a new iova alloc request comes iova is always searched > from the cached node and the nodes which are previous to cached > node. So, even if there is free iova space available in the nodes > which are next to the cached node iova allocation can still fail > because of this approach. > > Consider the following sequence of iova alloc and frees on > 1GB of iova space > > 1) alloc - 500MB > 2) alloc - 12MB > 3) alloc - 499MB > 4) free - 12MB which was allocated in step 2 > 5) alloc - 13MB > > After the above sequence we will have 12MB of free iova space and > cached node will be pointing to the iova pfn of last alloc of 13MB > which will be the lowest iova pfn of that iova space. Now if we get an > alloc request of 2MB we just search from cached node and then look > for lower iova pfn's for free iova and as they aren't any, iova alloc > fails though there is 12MB of free iova space. > > To avoid such iova search failures do a retry from the last rb tree node > when iova search fails, this will search the entire tree and get an iova > if its available > > Signed-off-by: Vijayanand Jitta > --- > drivers/iommu/iova.c | 19 +++++++++++++++---- > 1 file changed, 15 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c > index 0e6a953..7d82afc 100644 > --- a/drivers/iommu/iova.c > +++ b/drivers/iommu/iova.c > @@ -184,8 +184,9 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad, > struct rb_node *curr, *prev; > struct iova *curr_iova; > unsigned long flags; > - unsigned long new_pfn; > + unsigned long new_pfn, alloc_lo_new; > unsigned long align_mask = ~0UL; > + unsigned long alloc_hi = limit_pfn, alloc_lo = iovad->start_pfn; > > if (size_aligned) > align_mask <<= fls_long(size - 1); > @@ -198,15 +199,25 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad, > > curr = __get_cached_rbnode(iovad, limit_pfn); > curr_iova = rb_entry(curr, struct iova, node); > + alloc_lo_new = curr_iova->pfn_hi; > + > +retry: > do { > - limit_pfn = min(limit_pfn, curr_iova->pfn_lo); > - new_pfn = (limit_pfn - size) & align_mask; > + alloc_hi = min(alloc_hi, curr_iova->pfn_lo); > + new_pfn = (alloc_hi - size) & align_mask; > prev = curr; > curr = rb_prev(curr); > curr_iova = rb_entry(curr, struct iova, node); > } while (curr && new_pfn <= curr_iova->pfn_hi); > > - if (limit_pfn < size || new_pfn < iovad->start_pfn) { > + if (alloc_hi < size || new_pfn < alloc_lo) { > + if (alloc_lo == iovad->start_pfn && alloc_lo_new < limit_pfn) { > + alloc_hi = limit_pfn; > + alloc_lo = alloc_lo_new; > + curr = &iovad->anchor.node; > + curr_iova = rb_entry(curr, struct iova, node); > + goto retry; > + } > iovad->max32_alloc_size = size; > goto iova32_full; > } > ping? -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation