From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4BE363191BA; Fri, 10 Jul 2026 14:51:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783695073; cv=none; b=RMaVUAQHdBWKp8KL4IbEN6rl9kxd8jydu6p4ABIKgq0hn9j+aLW4FwhEkGJFSj2fin2hUTK8gdp6xeKuGmwgwwjFJ1R6cMVKT2PcoqsDicsf39y2HhYoKIcIjp+l0DAOkuPh1yJIS0yFVWxURvTPfbZoOBQpbUOkbDtH/MfOqEU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783695073; c=relaxed/simple; bh=HVCHZJFQAGlkuskJ7SayMhosIqfStBiyOTKFtFT5fdk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JdowGOYA6kcqCoWBOaON0YBx4rGBqhH6UgACOr9zrM43N9YtsQsTqBcgukxWI1OuPkZNj2rsL6I33CQG4qT8CxfgoxZv9bvsXmZ+p/VDk3HnNFlv+2182xYfwpFaEfKqNx9YqsYlwjJkidiqa9tySqhuNk7/6YuDFQaRVSoOk3o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GV0G1PCd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GV0G1PCd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A13DE1F00A3A; Fri, 10 Jul 2026 14:50:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783695069; bh=/adl28F1RG11+xFCTzjhiMT3/quSA/55SrYHe5Xl+as=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=GV0G1PCdVWL/17cPDVZfz86GmBO0VpAcpElRSgqzkFaZnFKsDK6rIw+lxzMvM7oyM gOb7BmlLZV+r7XfvVToV0An5vS3DWoiRNZEtakP1kgKdd/pwAzK/AhJrUnpZlFH/ma IDgVC6vlNuOfwFAEke1UlfCP3mMcmRNqv1rAQF1Ta5n8CDc7P/kP23VMlYUdFRkbMx btXD63gJA5fhI4bndbOxrinkAQhHaNvBor7RN1UECzz5h5BotHDkxdGHR0ZdFn1Wle sxRRlN3kLf8W7g8Lmmkim9s7ySe4W1NlivrC5VU8viOWzvoYYPKNt7/4lb6lTsMCz8 i1PWPp9WBYC/w== Date: Fri, 10 Jul 2026 15:50:44 +0100 From: Lorenzo Stoakes To: Gregory Price 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: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Jul 09, 2026 at 11:18:40AM -0400, Gregory Price wrote: > 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). Yeah I know, I do hope to refactor all this at some point to make it simpler, but for the time being tried to make the confusing thing at least _slightly_ less confusing :) > > ~Gregory Cheers, Lorenzo > > > + /* > > + * 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 > > + */