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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7D18C71136 for ; Fri, 13 Jun 2025 17:48:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 68C2E6B008A; Fri, 13 Jun 2025 13:48:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 63BFD6B008C; Fri, 13 Jun 2025 13:48:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 52ABF6B0092; Fri, 13 Jun 2025 13:48:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 3239E6B008A for ; Fri, 13 Jun 2025 13:48:41 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id B30FD1A0EDA for ; Fri, 13 Jun 2025 17:48:40 +0000 (UTC) X-FDA: 83551112400.17.412173B Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by imf08.hostedemail.com (Postfix) with ESMTP id 6A8D4160011 for ; Fri, 13 Jun 2025 17:48:38 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=fb.com header.s=facebook header.b=kpBk4Sg7; dmarc=pass (policy=reject) header.from=fb.com; spf=pass (imf08.hostedemail.com: domain of "prvs=2259912e91=amastro@meta.com" designates 67.231.145.42 as permitted sender) smtp.mailfrom="prvs=2259912e91=amastro@meta.com" ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1749836918; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=/u+aoBgzPCVoRGMt4BTTmEzoT0H40U+wuAoLeJzs7M4=; b=hJsOFPuvl7Iz07GB4mGKc9+5EnA0tK7BFeEH65Gmy/1JoB5K81sn0K/vaSyQahSJUTlCvQ iXCtlpapgmuip8kzy8f0S7R7BIrygQ0XjGnC39f7KQk1mwf/sZ+BjW3lWz13B6gmtNCDEq myUr0GJ/HEQt3/wVJsBaMQ+Mtf2q/GQ= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=fb.com header.s=facebook header.b=kpBk4Sg7; dmarc=pass (policy=reject) header.from=fb.com; spf=pass (imf08.hostedemail.com: domain of "prvs=2259912e91=amastro@meta.com" designates 67.231.145.42 as permitted sender) smtp.mailfrom="prvs=2259912e91=amastro@meta.com" ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1749836918; a=rsa-sha256; cv=none; b=sYUqBf/EmTKaYR5tFlHD930WmPsWcH5OnBeuzt4munlZzmGtTf4QTW794FuYVVCsLzHqmt hkyaEaAJdDnvpv2bfNT7mHAah46Bz+dC+M0itfCTcBgBBZvsrckuQJDdDn0sri5P/PyJCU z4SxcUa2QpL+jlHf+/jB20xt/vKYWcQ= Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 55DGBpNP004108 for ; Fri, 13 Jun 2025 10:48:37 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=facebook; bh=/ u+aoBgzPCVoRGMt4BTTmEzoT0H40U+wuAoLeJzs7M4=; b=kpBk4Sg7CPto28VD+ 7+QC48Df1hESGLLuvGoW7Hx6Oyw9PKvhOtP+M+KBtZTSTDO3GCyFg1Q0zIvFVECw Du8FAXKxR89qgr0wjC6/0qfOSDMBk6JO5xpUSbYMT/07jguYd/2Hqq7/T4t2DHkS DAtC/Li4S0yAcxRee/2mAb3BcM= Received: from mail.thefacebook.com ([163.114.134.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 478gfb41mn-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 13 Jun 2025 10:48:37 -0700 (PDT) Received: from twshared11388.16.prn3.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c08b:78::c78f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.2.1748.24; Fri, 13 Jun 2025 17:48:36 +0000 Received: by devgpu004.cco5.facebook.com (Postfix, from userid 199522) id 63433413CC1; Fri, 13 Jun 2025 10:46:11 -0700 (PDT) From: Alex Mastro To: CC: , , , , , , , , , Alex Mastro Subject: Re: [PATCH 5/5] vfio-pci: Best-effort huge pfnmaps with !MAP_FIXED mappings Date: Fri, 13 Jun 2025 10:44:42 -0700 Message-ID: <20250613174442.1589882-1-amastro@fb.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250613134111.469884-6-peterx@redhat.com> References: <20250613134111.469884-6-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-ORIG-GUID: nNP5oGq-HtPU0or6DdWhr93tTpXsUid1 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNjEzMDEyNyBTYWx0ZWRfXx5wQt85n57V2 5BjRZZkuvF7Bl68+9FrpXgjZ1jYqHXc/DkSLn8HAEqU0/bfeeP6gTLQG4DzQXatXB/HMAlKiNsA nYLZeXud2hD8KXxN10rQ9qk9iaeT20CH8hTEB33Oi1RO13N7VHF4DZxZbKuAMxp3BeLwqrHIqbf kpRfP72CKFesoUpqBudhPJOFPILXCH9caH1Q4j9WA83QnhxrHz9vLYl5aaG3pHuphOcJ7tsyT3w ztsMY/U6Y3/jhxM1o1b6cYIdDWAF7zqHawLyvDmlWpme/inwdHOquNuiWhGoXHhEPu2ACrBNU1+ Z2l1AUmm4DpEORTGQZr0oVxBwKlmx2+ix33T+Ff0dldDXBFcEE7qzqWTbamI0fpyB9PsoGoLTt4 6VY8kh6rx5CMh5obemBzG7AJQMBjV9tTJbRhEvl9ZwENIiuT1EDYB0EMJ+Y71FBLA2TBPZvM X-Proofpoint-GUID: nNP5oGq-HtPU0or6DdWhr93tTpXsUid1 X-Authority-Analysis: v=2.4 cv=WsMrMcfv c=1 sm=1 tr=0 ts=684c6475 cx=c_pps a=CB4LiSf2rd0gKozIdrpkBw==:117 a=CB4LiSf2rd0gKozIdrpkBw==:17 a=6IFa9wvqVegA:10 a=VwQbUJbxAAAA:8 a=FOH2dFAWAAAA:8 a=jZ9vbDvHQ2ocIyg0wPEA:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.0.736,FMLib:17.12.80.40 definitions=2025-06-13_02,2025-06-13_01,2025-03-28_01 X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 6A8D4160011 X-Stat-Signature: ipp1t5co46hiz38jxz9s9u7s45dtztpo X-Rspam-User: X-HE-Tag: 1749836918-916715 X-HE-Meta: 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 S98x++H7 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Thank you Peter! I packported this series to our 6.13.2 tree and validated that it does in= deed provide equivalent, optimal faulting to our manual alignment approach whe= n we mmap with !MAP_FIXED. This addresses the issue we discovered in [1]. The test case is performing mmap with offset=3D0x40006000000, size=3D0xdf= 9e00000, and we see that the head and tail (975) are faulted at 2M, and middle (54= ) at 1G. The vma returned by mmap looks nice: 0x7f8646000000. $ sudo bpftrace -q -e 'fexit:vfio_pci_mmap_huge_fault { printf("order=3D%= d, ret=3D0x%x\n", args.order, retval); }' 2>&1 > ~/dump $ cat ~/dump | sort | uniq -c | sort -nr 975 order=3D9, ret=3D0x100 54 order=3D18, ret=3D0x100 2 order=3D18, ret=3D0x800 [1] https://lore.kernel.org/linux-pci/20250529214414.1508155-1-amastro@fb= .com/ Tested-by: Alex Mastro