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=-9.6 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,USER_AGENT_GIT 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 5D91BC28CBC for ; Wed, 6 May 2020 20:03:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 356CF2070B for ; Wed, 6 May 2020 20:03:05 +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="M9DQmflz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727970AbgEFUDE (ORCPT ); Wed, 6 May 2020 16:03:04 -0400 Received: from mail27.static.mailgun.info ([104.130.122.27]:64042 "EHLO mail27.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725966AbgEFUDE (ORCPT ); Wed, 6 May 2020 16:03:04 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1588795384; h=Message-Id: Date: Subject: Cc: To: From: Sender; bh=0qIdTUUATMq8n20RL86MZF5csAq5w4nM1wfS8+2VTvs=; b=M9DQmflzQrgA6Yh+1R8P3RJn8gs3tIfveR6TovryIrbeFORAxqHZPorje+svnroZcyAsEug/ CFVXxON/Vd41EGjKZBO7weKyj2ZHP+yDlVWkwqNDcAfc/Oj86HJxMYV4ckT9fZbAA6LCnz/Q a97SFlbqVEqYHm5tCAvU8nqLOcs= X-Mailgun-Sending-Ip: 104.130.122.27 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 5eb317f5.7fa7ba007dc0-smtp-out-n03; Wed, 06 May 2020 20:03:01 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 6A3B6C433F2; Wed, 6 May 2020 20:03:00 +0000 (UTC) Received: from vjitta-linux.qualcomm.com (blr-c-bdr-fw-01_GlobalNAT_AllZones-Outside.qualcomm.com [103.229.19.19]) (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 DE3C8C433BA; Wed, 6 May 2020 20:02:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org DE3C8C433BA 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, vjitta@codeaurora.org Subject: [PATCH] iommu/iova: Retry from last rb tree node if iova search fails Date: Thu, 7 May 2020 01:31:57 +0530 Message-Id: <1588795317-20879-1-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 | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index 0e6a953..2985222 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -186,6 +186,7 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad, unsigned long flags; unsigned long new_pfn; unsigned long align_mask = ~0UL; + bool retry = false; if (size_aligned) align_mask <<= fls_long(size - 1); @@ -198,6 +199,8 @@ 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); + +retry_search: do { limit_pfn = min(limit_pfn, curr_iova->pfn_lo); new_pfn = (limit_pfn - size) & align_mask; @@ -207,6 +210,14 @@ static int __alloc_and_insert_iova_range(struct iova_domain *iovad, } while (curr && new_pfn <= curr_iova->pfn_hi); if (limit_pfn < size || new_pfn < iovad->start_pfn) { + if (!retry) { + curr = rb_last(&iovad->rbroot); + curr_iova = rb_entry(curr, struct iova, node); + limit_pfn = curr_iova->pfn_lo; + retry = true; + goto retry_search; + } + 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