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 BD8DDC43458 for ; Thu, 9 Jul 2026 15:18:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1CDFC6B0098; Thu, 9 Jul 2026 11:18:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 17E506B0099; Thu, 9 Jul 2026 11:18:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F3BBF6B009B; Thu, 9 Jul 2026 11:18:50 -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 AC8446B0098 for ; Thu, 9 Jul 2026 11:18:50 -0400 (EDT) Received: from smtpin29.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 337741C1575 for ; Thu, 9 Jul 2026 15:18:50 +0000 (UTC) X-FDA: 84969595620.29.13A2936 Received: from mail-qt1-f177.google.com (mail-qt1-f177.google.com [209.85.160.177]) by imf28.hostedemail.com (Postfix) with ESMTP id 425A6C0007 for ; Thu, 9 Jul 2026 15:18:48 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=gourry.net header.s=google header.b=CiMrjRrr; spf=pass (imf28.hostedemail.com: domain of gourry@gourry.net designates 209.85.160.177 as permitted sender) smtp.mailfrom=gourry@gourry.net; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1783610328; 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=D66HPeIJnm5ZDnK+VorUOpyiniaZPeUCt2fPIKMnyb4=; b=sJRSyCBX7+6EhGvk0lfc2hZxaj8ZGhXJ05UGO/+cCvFgz0C3AeAuX4dd7qhYt7NNHXX14r 5n2DCPuMs14nbaqvwe/sC6NCziFtaaZH3GzTBaEz5hHzjxjlMfgJMOj1pFFWeGnm4Y86V/ REC7d4hYQwUW4emnazjOpR1TqMZHLmM= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1783610328; b=lKpeSJigK1lk0UFiAC8h7DhsrfhOoxjpJjUKOk400cUqvwKTGALU59ggzeCmfaIGEPkkGU HlXGEW6u522cuF+p+oL4yQCcixy2YdsgtApk0FjnTfFzmpFaImBSnPAYDXbDx0lbHcMmqF fIlc8DdPHhqducSxUQOLPRE7IjU/NTw= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=gourry.net header.s=google header.b=CiMrjRrr; spf=pass (imf28.hostedemail.com: domain of gourry@gourry.net designates 209.85.160.177 as permitted sender) smtp.mailfrom=gourry@gourry.net; dmarc=none Received: by mail-qt1-f177.google.com with SMTP id d75a77b69052e-51c4436d02cso9165151cf.1 for ; Thu, 09 Jul 2026 08:18:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1783610327; x=1784215127; 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=D66HPeIJnm5ZDnK+VorUOpyiniaZPeUCt2fPIKMnyb4=; b=CiMrjRrrmROfY0qDtON6pqzEjLpj+emHUu43zYNd+Ke9nxsFp7dYpxsd54A62n20Ux 6GhRPmbq8vTEAZEDHzaAaw2F5hew6M2dXmGjbn+4WO3vS8HVXTrGRDBpago1OO6vcWda chgp2tVZhRIG/Jj+pJKreSP1Y8ujAIdCwISqDu13DZECelzyFcHTIr7PccM6JEdqIMGZ pTVjvw9UFJSnP4nPmiR9glw3+tNXTZlECKt3XilezMIXUv7EOj29+hhTVX10jOjCYY2n SNSzaf352k4Y2elZjAn8AuPSh7P5JSN4OIUxxoON3BZO4iPONFMZtbh5A0plOmBH4Gac fDkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783610327; x=1784215127; 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=D66HPeIJnm5ZDnK+VorUOpyiniaZPeUCt2fPIKMnyb4=; b=KEsjsL3pC+lpiHoLHTKIg3SC1sWXDSYpzPEYYgJRqlGBVqDBopJ8We4iEiVaOB0FUD mXMelp9ZG+YSntskmnMiVMzz4HP2LqW/ZQvKnGtV2gXiuQVyz3HdY6NUlwqWD/YiwUDR jWQ9+5oJawJZVdDpyFnx/jKvHMBYbZPMMmLTxH/nWBUYOpBDfPrWE4nOo8l+CJOVTgcr c7J3BNcvH6+HALQvDeskPQQkw2VsGH42OVqTVBSEOaB+rc9K9NHBbT+AcDnUr7ynnBM5 rFNK/J1z4E6sfF2SBvdB8f4JgeHdFyo98pwcem6aN4lDY9qDXbDvZBKXORydrGn66wCE iIkQ== X-Forwarded-Encrypted: i=1; AHgh+RrAVwlJhPPZdPjD7OUatum6NoH+og+Hmq/3ZfOwhR4uoKGHjFyvkmTi3Yqq+/5bfEVP+tLQ0G26DQ==@kvack.org X-Gm-Message-State: AOJu0Yw5hdscrAcV7xwEvS0hzVqOj+tADnxzwUICfP3OTo1j/qavucXG 3Qw1PNcQAmDxj6wPUuUUTar1iMpPf0QXRPveBjn3Q9/kobnzNTmAfBW7yI/OkLgVMxU= X-Gm-Gg: AfdE7cnNixoKK/WRi7UmM0r1Csw8A/SWiVsaefNL5foB+Un3y+Pbt6ND+E3bF373Kdd RZj0GryEBBS2zhP23yf1Au3wYLSUZSMSRXgiOYGqa+S2AqEELq0AKRciO14KoRgv++wT+vu3Iip 1vFv1xA3bJ22DxITsQx+VlNPxroZsYV5IGyZ0a8bGrVr0GKO+4oo5zUFVBfjop7KHlt8789X6jc xhU2dpn0obvqc2ZQiu9c0Phxs4GC6KjBvnkD5Db6Kkxm2wnqm1hrbtIGmCuSxG/Xx3jtMmQd61m W/02JW67glBxNaUGk3JWGjfXyAUC4VxteBUhuE5EFQBRi1GV6pX6LSLFWpttp1N+GXUbHs4RhE/ Ogc6Go9jjgkzEAYdj1aMrdmUIGp6LJtYS3bN+AuO5mEevCWeUDDWjwml5wrEobQcaNdkkWMZiSI 1ytr3Yb9UFWSkeGv6fu9evJBR947ie2oh210FLfLKNG2pme44mOUewvtVoPohoczuGo0KYzrDKB bN/U+0= X-Received: by 2002:ac8:5cd4:0:b0:51c:1c2c:a8c9 with SMTP id d75a77b69052e-51c8b3e2e32mr79753441cf.43.1783610327278; Thu, 09 Jul 2026 08:18:47 -0700 (PDT) Received: from gourry-fedora-PF4VCD3F (pool-173-79-60-52.washdc.fios.verizon.net. [173.79.60.52]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-51c41db4fb5sm158006781cf.25.2026.07.09.08.18.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 09 Jul 2026 08:18:45 -0700 (PDT) Date: Thu, 9 Jul 2026 11:18:40 -0400 From: Gregory Price To: Lorenzo Stoakes Cc: Andrew Morton , Russell King , Dinh Nguyen , Simon Schuster , "James E . J . Bottomley" , Helge Deller , Jarkko Sakkinen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Ian Abbott , H Hartley Sweeten , Lucas Stach , David Airlie , Simona Vetter , Patrik Jakobsson , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Clark , Dmitry Baryshkov , Tomi Valkeinen , Thierry Reding , Mikko Perttunen , Jonathan Hunter , Christian Koenig , Huang Rui , Ankit Agrawal , Alex Williamson , Alexander Viro , Christian Brauner , Dan Williams , Muchun Song , Oscar Salvador , David Hildenbrand , Suren Baghdasaryan , "Liam R . Howlett" , Matthew Wilcox , Marek Szyprowski , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Masami Hiramatsu , Oleg Nesterov , Steven Rostedt , SeongJae Park , Miaohe Lin , Hugh Dickins , Mike Rapoport , Kees Cook , Paolo Bonzini , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-parisc@vger.kernel.org, linux-sgx@vger.kernel.org, etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-tegra@vger.kernel.org, kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev, linux-mm@kvack.org, iommu@lists.linux.dev, linux-perf-users@vger.kernel.org, linux-trace-kernel@vger.kernel.org, kasan-dev@googlegroups.com, damon@lists.linux.dev, Pedro Falcato , Rik van Riel , Harry Yoo , Jann Horn Subject: Re: [PATCH 13/30] mm/vma: refactor vmg_adjust_set_range() for clarity Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 425A6C0007 X-Stat-Signature: bjkswa4o3tiw8m9ctox5rrz33oz98xbx X-HE-Tag: 1783610328-539209 X-HE-Meta: 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 6ZIQxehJ 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jun 29, 2026 at 01:23:24PM +0100, Lorenzo Stoakes wrote: > Add comments with ASCII diagrams to describe what we're doing, avoid > dubious use of PHYS_PFN(), and use vma_start_pgoff(). > > The most complicated scenario represented here is vmg->__adjust_next_start > - when this is set, vmg->[start, end] actually indicate the range to be > retained, so take special care to describe this accurately. > > No functional change intended. > > Signed-off-by: Lorenzo Stoakes Reviewed-by: Gregory Price > + /* > + * vmg->start vmg->end > + * | | > + * v merge v > + * <-------------> > + * delta > + * <------> > + * |------|----------------| > + * | prev | middle | > + * |------|----------------| > + * ^ > + * | > + * middle->vm_start > + */ Even with these diagrams, it's a bit difficult to understand what the actual intent/result of this chunk is (but that may be a limitation of me not spending enough time reading the surrounding code, not a comment of your work here). ~Gregory > + /* > + * Originally: > + * > + * vmg->start vmg->end > + * | | > + * v merge v > + * <------------> > + * . . > + * merge_existing_range() updates to: > + * . . > + * vmg->start vmg->end . > + * | | . > + * v retain v . > + * <----------> . > + * delta . > + * <-----> . > + * |----------------|------| > + * | middle | next | > + * |----------------|------| > + * ^ > + * | > + * next->vm_start > + */