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=-12.5 required=3.0 tests=BAYES_00,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_GIT autolearn=unavailable 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 59F9DC433E1 for ; Thu, 20 Aug 2020 12:50:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 339272086A for ; Thu, 20 Aug 2020 12:50:17 +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="jg6X0gcU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729184AbgHTMuP (ORCPT ); Thu, 20 Aug 2020 08:50:15 -0400 Received: from m43-7.mailgun.net ([69.72.43.7]:16026 "EHLO m43-7.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729986AbgHTMtp (ORCPT ); Thu, 20 Aug 2020 08:49:45 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1597927784; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=BhNeirievu7ABUQ2mRSmIu+sWUN4ihC6bWjNuJCyjvc=; b=jg6X0gcUrStaNIZaXRDpTvvLaby7WD8j50rS/vKiGZTrgoswqwPKQ1W/r2DiEfX4zpVk5PCf MEiXW6KzgknlhS5W9d3bQ+YWpFU9zIpth7iBf4dNpeMvjrj8onKKW2HvVwDLNaAsm0wS45Ki tfh5qAtR2SHGd2AyT1fdabgHcaI= X-Mailgun-Sending-Ip: 69.72.43.7 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 smtp-out-n03.prod.us-east-1.postgun.com with SMTP id 5f3e716755574eb3e8949855 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Thu, 20 Aug 2020 12:49:43 GMT Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 52474C43395; Thu, 20 Aug 2020 12:49:42 +0000 (UTC) Received: from vjitta-linux.qualcomm.com (unknown [202.46.22.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vjitta) by smtp.codeaurora.org (Postfix) with ESMTPSA id 6C862C433CA; Thu, 20 Aug 2020 12:49:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 6C862C433CA 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 From: vjitta@codeaurora.org To: joro@8bytes.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Cc: vinmenon@codeaurora.org, kernel-team@android.com, robin.murphy@arm.com, vjitta@codeaurora.org Subject: [PATCH v2 1/2] iommu/iova: Retry from last rb tree node if iova search fails Date: Thu, 20 Aug 2020 18:19:20 +0530 Message-Id: <1597927761-24441-1-git-send-email-vjitta@codeaurora.org> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 49fc01f..4e77116 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, low_pfn_new; unsigned long align_mask = ~0UL; + unsigned long high_pfn = limit_pfn, low_pfn = 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); + low_pfn_new = curr_iova->pfn_hi + 1; + +retry: do { - limit_pfn = min(limit_pfn, curr_iova->pfn_lo); - new_pfn = (limit_pfn - size) & align_mask; + high_pfn = min(high_pfn, curr_iova->pfn_lo); + new_pfn = (high_pfn - 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) { + } while (curr && new_pfn <= curr_iova->pfn_hi && new_pfn >= low_pfn); + + if (high_pfn < size || new_pfn < low_pfn) { + if (low_pfn == iovad->start_pfn && low_pfn_new < limit_pfn) { + high_pfn = limit_pfn; + low_pfn = low_pfn_new; + curr = &iovad->anchor.node; + curr_iova = rb_entry(curr, struct iova, node); + goto retry; + } iovad->max32_alloc_size = size; goto iova32_full; } -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation 1.9.1