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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AE413C44506 for ; Fri, 10 Jul 2026 16:27:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 80E906B008A; Fri, 10 Jul 2026 12:27:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7BF086B008C; Fri, 10 Jul 2026 12:27:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6AEFA6B0092; Fri, 10 Jul 2026 12:27:54 -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 42FAB6B008A for ; Fri, 10 Jul 2026 12:27:54 -0400 (EDT) Received: from smtpin11.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id C58D01C3C4E for ; Fri, 10 Jul 2026 16:27:53 +0000 (UTC) X-FDA: 84973398426.11.1B992B4 Received: from mail-qv1-f44.google.com (mail-qv1-f44.google.com [209.85.219.44]) by imf03.hostedemail.com (Postfix) with ESMTP id CBD9D20009 for ; Fri, 10 Jul 2026 16:27:51 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=ziepe.ca header.s=google header.b=ilmKDi0L; spf=pass (imf03.hostedemail.com: domain of jgg@ziepe.ca designates 209.85.219.44 as permitted sender) smtp.mailfrom=jgg@ziepe.ca; dmarc=none ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1783700871; b=dPl+WPGqFzJBla5n9jUbzRM5gTXgkfQR3snSSbB2FPC+X/Ohxr3rNMiaMNd+iwAg1YcBDJ bD1e/fQoi6HICrvngQ7xE02I/T08TrjDjrBTNt6TCdqPteY+eWMrIIiUhNQNru+9EtxbxL lhyZflw/CXNnyXlBqKVhWdQA6rfW40c= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=ziepe.ca header.s=google header.b=ilmKDi0L; spf=pass (imf03.hostedemail.com: domain of jgg@ziepe.ca designates 209.85.219.44 as permitted sender) smtp.mailfrom=jgg@ziepe.ca; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1783700871; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=UNIXCm8Zus/z4nQ3xLBTLCwOawMM/+5sDMMsd2dm66E=; b=zzPPlaxGwrUILVqI6Ya2i/GxwLSoYDF6F0wFu7gbSPGEo/VsiCsQ7VwLEs27XlUq3VZgu5 IwrqNtpJwGHYt9XfAJWMs0vvi0N/adNaFUHWLGUvYfldQLYpxAw2ZRGLER59yfRoq1voVX gsQd92kOtKqEFmEtqjDR9sx573uW/tw= Received: by mail-qv1-f44.google.com with SMTP id 6a1803df08f44-8ff88549786so10835836d6.3 for ; Fri, 10 Jul 2026 09:27:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1783700871; x=1784305671; darn=kvack.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=UNIXCm8Zus/z4nQ3xLBTLCwOawMM/+5sDMMsd2dm66E=; b=ilmKDi0LiVY492j/FuBGvLOGhmE0XHrIN/liU0eSxombFocfxKcZfiYuaAXJtRe/if uILGq3oGyBo0kTiRVqBbEBTGqqIY3bra6lWCZY0LwEk7UxwyhAihGlghxcDNI0tIHOBx JPNNhJ99J9Fqc2rt9PNb8rWSFPEd4aDw8t3QN/Lo63u1bGEAFDAb4ddeuLl2jiEDnXMb noQ7IqmVwKlZ9RqZcwNNCVbR46wegtqk8saxCSdy1Naik4SXh/tEi4qVkmeFA9fgJ1H1 4ybH/1dyD62u2/4fAbuH/zuvaNVVANLx7ynJnTAS62DN+p4SyhMOgtzalq+wuaNUtDKW DaFw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783700871; x=1784305671; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=UNIXCm8Zus/z4nQ3xLBTLCwOawMM/+5sDMMsd2dm66E=; b=P9xYNWG8JQDFSVznRt+GvUL5GCLmm2YMKaJ13RVy0PfCwbztP8iw6rHBl5hbRI/mVj 4F+gW9b8ZLQ5ZRkVAEFknqHp3p0wDjrrUxHhD3i/03MJCF5KAOyuLc0xYpNunaj67FS8 EUlybYqOeOZC5uVzqLGykRgCkjTgOgIaeFrxkr4QsVf2/aOqw3LolBbzMO3thCPaKeJ3 3fy9xF6BujYaFQzERnxUbiWQ2SI+JJIuC67T6vcEwE1DFrM5vQKXFvzKD4dR/+EuNAYJ aAFcVOgz2gE0mf3f89Vs7v339KO4mulJV+JKVLEUTyaBQDgGuFIcaf+GPoq3Zg/PlRQh Kj6w== X-Forwarded-Encrypted: i=1; AHgh+RrMWavbiLXN1vpBJQk3aJaxHulgB/hHLSIcRv75dRT8GkUnjzLoztZgA2Y+rvZ+/Chp4lqvEwspNQ==@kvack.org X-Gm-Message-State: AOJu0YyeDc+5lc1FzY95VhjP1aNoTar1LA3jfuhl5LhMdG/aT3sko6G9 oCm/EN9dBhx+/uZheJqdzoYRjvYwMsvvfAhAKcDyOl84Lsb9PnA6ZSMg2NuB14Lj2PY= X-Gm-Gg: AfdE7clNU/Gizp5YyEN++CKDYMHbZ5y01RPeYk3jfYwV6p5Y43Hnmp64zYQeg+9AX+U fJjH9S3e0njQajtA8F2meGNTB78pqG2ph6R/lgudHl9Ymu45VpTUw8mBHL3OWC10UYZzjqD9IUl Jg9ZRZ+mMLbAsBGwWTwbBuFZLnuPewQ6nNOKhyyabMAKuLPr9Z3lwpR26Yk63hKnqsUmMRi200I eDHvU0Ao42SpgmDD/KlBH7ZcsObH5ZSL3aAJY3jGuh7MClXJYu1Mm2kzLroU+CBUKC0cgICih/C 0INi9TobLnLIrC3WGccCey8p+CjDz9aPKNhKDptoMzGtKq++caDrvrZxL6MFspnbWQQ5V0punG9 OwWVBICUQs+LiWPhDinhi2rb9K4ehXBIUs3wWvBRFPoFB/vzlTaCsw93IXjnnH7Qy+qXheOw= X-Received: by 2002:a05:6214:2127:b0:8f5:eea1:6f04 with SMTP id 6a1803df08f44-8fec3522cffmr120531466d6.54.1783700870475; Fri, 10 Jul 2026 09:27:50 -0700 (PDT) Received: from ziepe.ca ([159.2.72.92]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8ffd50e081dsm44781476d6.9.2026.07.10.09.27.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Jul 2026 09:27:49 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wiE4r-00000007XPF-1WDC; Fri, 10 Jul 2026 13:27:49 -0300 Date: Fri, 10 Jul 2026 13:27:49 -0300 From: Jason Gunthorpe To: Stanislav Kinsburskii Cc: airlied@gmail.com, akhilesh@ee.iitb.ac.in, akpm@linux-foundation.org, corbet@lwn.net, dakr@kernel.org, david@kernel.org, decui@microsoft.com, haiyangz@microsoft.com, kees@kernel.org, kys@microsoft.com, leon@kernel.org, liam@infradead.org, lizhi.hou@amd.com, ljs@kernel.org, longli@microsoft.com, lyude@redhat.com, maarten.lankhorst@linux.intel.com, mamin506@gmail.com, mhocko@suse.com, mripard@kernel.org, nouveau@lists.freedesktop.org, ogabbay@kernel.org, oleg@redhat.com, rppt@kernel.org, shuah@kernel.org, simona@ffwll.ch, skhan@linuxfoundation.org, surenb@google.com, tzimmermann@suse.de, vbabka@kernel.org, wei.liu@kernel.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-rdma@vger.kernel.org Subject: Re: [PATCH v7 2/8] mm/hmm: add hmm_range_fault_unlocked_timeout() for mmap lock-drop support Message-ID: <20260710162749.GP118978@ziepe.ca> References: <178345345668.660027.2952911919681614557.stgit@skinsburskii> <178345362182.660027.12809852179204464964.stgit@skinsburskii> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <178345362182.660027.12809852179204464964.stgit@skinsburskii> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: CBD9D20009 X-Stat-Signature: qs71ocikbgkorgyz1jb57uqqgfdn9srd X-HE-Tag: 1783700871-368474 X-HE-Meta: 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 OE9VY/UR Xdj/Eb0+ZZL/rFcHMFIFm4a0EUvA3iAxcn9R+NTMOzOyS/nl1ZuS7Wd+pxu3X/c6Mz4iS11PP/yHOhC/G15j6xwQ1t8qzjcUKJ/n3LucyNc6EHl9jTpNjftU2SwipYHSif0+F1lHQhgnkkQ8gGSSwjGdjBWQX++Da0agoP5I/wBV5cND3ZLPCFgBUiFMt3DQSQl/3xglLNtpxdZWglMg4w5lr5dsubttwm4eFTLJAnF4paVfRZNLHuhFTclzpH2gbtMuruOIVNJTevOODQJsfSJKh9FCQpsnPCUiFw30dOsB7vRt7Ewj5l6QZ4cWJ4XK6ofTyT4poZspsw1xeIKgQFIT75BSnAxAv6glPk19r9TeX+vw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jul 07, 2026 at 12:47:01PM -0700, Stanislav Kinsburskii wrote: > +int hmm_range_fault_unlocked_timeout(struct hmm_range *range, > + unsigned long timeout) > +{ > + struct mm_struct *mm = range->notifier->mm; > + unsigned long deadline = 0; > + int locked, ret; > + > + if (timeout) > + deadline = jiffies + timeout; > + > + do { > + if (fatal_signal_pending(current)) > + return -EINTR; > + > + if (timeout && time_after(jiffies, deadline)) > + return -EBUSY; I really dislike there is a timeout here, HMM is supposed to be more deterministic. GUP doesn't have a timeout, what is this about? Jason