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[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: Precedence: bulk X-Mailing-List: linux-perf-users@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 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 > + */