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Date: Fri, 18 Sep 2026 08:44:42 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: liam@infradead.org, ljs@kernel.org, vbabka@kernel.org, david@kernel.org,
 willy@infradead.org, jannh@google.com, paulmck@kernel.org,
 pfalcato@suse.de, xueyuan.chen21@gmail.com, linux-mm@kvack.org,
 linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v5 0/7] read proc/pid/smaps_rollup under per-vma lock
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On Fri, 18 Sep 2026 08:33:11 -0700 Suren Baghdasaryan <surenb@google.com> wrote:

> proc/pid/smaps_rollup can be read using the combination of RCU and
> VMA read locks, similar to proc/pid/{maps|smaps|numa_maps}. RCU is
> required to safely traverse the VMA tree and VMA lock stabilizes the
> VMA being processed and the pagetable walk.
> Note that we have to keep the logic to drop mmap_lock on contention
> because even when using per-VMA locks we might have to fall back to
> holding the mmap_lock.
> 
> The first 5 patches are cleanups making later change simpler. The main
> change is in patch 6. Patch 7 extends existing proc-maps-race tearing
> test to verify smaps_rollup content.

Thanks, I added this to mm.git's mm-new branch.