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Thu, 27 Aug 2026 02:26:46 -0700 (PDT) Date: Thu, 27 Aug 2026 11:26:45 +0200 From: Michal =?utf-8?Q?Koutn=C3=BD?= To: Ridong Chen Cc: sashiko-reviews@lists.linux.dev, tj@kernel.org, hannes@cmpxchg.org, "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" Subject: Re: [RFC PATCH] mm/mglru: fix ineffective memory protection for non-kswapd reclaim Message-ID: References: <20260826133054.88529-1-ridong.chen@linux.dev> <20260826134733.051941F000E9@smtp.kernel.org> <0c606cf9-2b5a-4549-8ab1-0be619487412@linux.dev> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="xzefaujiz7w5j4fo" Content-Disposition: inline In-Reply-To: <0c606cf9-2b5a-4549-8ab1-0be619487412@linux.dev> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 3155720009 X-Stat-Signature: j4c31rxb6dxio7euryenw9t4ziyoh71m X-Rspam-User: X-HE-Tag: 1787822809-907269 X-HE-Meta: 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 Vp4ihUtb O2gO61/+loOZqCQkuDSrGkHdPZHizwNs14yxLJjpUM3YvUL4zwxmK0NH696LFNY8Xr7UIEyHsI/65/99mU6/4L1a0UksjdTTN8OzOvKFLS9E7xMKHjPl5PzkOm4JDgQaElIwj/MgWwK9Gw4gR0Mg/bgpIT6Uq4/YpZHLEgEfu7IrWn9sO3r7Mk8xu3zuQhicjzKk3kc3lR2EXlXNDyhQw5h3RlHK0b0x2Ba4h+WVPmwcV6jY2qkmiMXiO0FyJcoEohD5/g3m8z2akHUEtwDkcBAzQz+VbVluKw8zZCXlv9GgJPFgR3i7l3JCmX9/mljPuF7aGWOud2DfHVrQhYOz0+gikHeKMPzMcu5ajhE54kebLXJhaYMNg+L5JX3pqvqohXdfkhET7v8OcwvXn5+Btd0FS+YuYzY30rfEh5IF95VQqZ1bPfpL/rznc1izNZCWAuVK7m1HeTEXGFqKCwlA6gtoCRmfRijW5dRdO Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: --xzefaujiz7w5j4fo Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Subject: Re: [RFC PATCH] mm/mglru: fix ineffective memory protection for non-kswapd reclaim MIME-Version: 1.0 Hi Ridong. On Thu, Aug 27, 2026 at 09:29:13AM +0800, Ridong Chen wrote: > On 8/26/2026 9:47 PM, sashiko-bot@kernel.org wrote: > > Thank you for your contribution! Sashiko AI review found 1 potential is= sue(s) to consider: > >=20 > > Pre-existing issues: > > - [High] Integer overflow in `effective_protection()` calculations on s= ystems with >=3D 16TB RAM. > > -- > >=20 >=20 > Thanks for the careful analysis. You're right that this is pre-existing in > effective_protection() and not introduced by this patch. >=20 > I'm not sure it's worth fixing in practice, though =E2=80=94 the overflow= requires > systems with >=3D 16TB of RAM, which I've never encountered > myself. So I'd rather not fold a fix for it into this patch. >=20 > I'd like to hear the maintainers' thoughts on whether this is worth > addressing separately. Machines with >=3D16 TiB aren't completely out of reach [1]. Then configuring such protections to attain the overflow is another condition, so I'd consider this a nice to have but not a pressing fixup (separately, with thorough review of occurences where total page counts/bytes might get multiplied). HTH, Michal [1] E.g. https://aws.amazon.com/ec2/instance-types/u7i/ --xzefaujiz7w5j4fo Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iJEEABYKADkWIQRCE24Fn/AcRjnLivR+PQLnlNv4CAUCapACwBsUgAAAAAAEAA5t YW51MiwyLjUrMS4xMiwyLDIACgkQfj0C55Tb+AjofAD+NsuFu0PDFJHyrulcXKzI igkF85NY5/lYAU523FvrLmwBAKSa/iEpzYpKL0GrbsrBCZng/5QlqrJuwRFlL0SD bvIF =UNaW -----END PGP SIGNATURE----- --xzefaujiz7w5j4fo--