linux-kernel - Re: [PATCH v4 7/7] mm/maps: execute PROCMAP

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Message-ID: <CAEf4BzYxOfk3_dTmQY4hkx-6f+OqpCOL0agY1x=9LM08py+s+A@mail.gmail.com>
Date: Fri, 13 Jun 2025 13:36:26 -0700
From: Andrii Nakryiko <andrii.nakryiko@...il.com>
To: Suren Baghdasaryan <surenb@...gle.com>
Cc: akpm@...ux-foundation.org, Liam.Howlett@...cle.com, 
	lorenzo.stoakes@...cle.com, david@...hat.com, vbabka@...e.cz, 
	peterx@...hat.com, jannh@...gle.com, hannes@...xchg.org, mhocko@...nel.org, 
	paulmck@...nel.org, shuah@...nel.org, adobriyan@...il.com, brauner@...nel.org, 
	josef@...icpanda.com, yebin10@...wei.com, linux@...ssschuh.net, 
	willy@...radead.org, osalvador@...e.de, andrii@...nel.org, 
	ryan.roberts@....com, christophe.leroy@...roup.eu, tjmercier@...gle.com, 
	kaleshsingh@...gle.com, linux-kernel@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, linux-mm@...ck.org, 
	linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v4 7/7] mm/maps: execute PROCMAP_QUERY ioctl under per-vma locks

On Wed, Jun 4, 2025 at 4:12 PM Suren Baghdasaryan <surenb@...gle.com> wrote:
>
> Utilize per-vma locks to stabilize vma after lookup without taking
> mmap_lock during PROCMAP_QUERY ioctl execution. While we might take
> mmap_lock for reading during contention, we do that momentarily only
> to lock the vma.
> This change is designed to reduce mmap_lock contention and prevent
> PROCMAP_QUERY ioctl calls from blocking address space updates.
>
> Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
> ---
>  fs/proc/task_mmu.c | 56 ++++++++++++++++++++++++++++++++++++----------
>  1 file changed, 44 insertions(+), 12 deletions(-)
>

The overall approach in this patch set looks good to me! PROCMAP_QUERY
changes specifically are pretty straightforward, nice. LGTM:

Acked-by: Andrii Nakryiko <andrii@...nel.org>

And for the rest of the changes you seem to be in good hands, so I'll
just be waiting for the final thing to land, thanks for working on
this!