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b=KW2YAXJCNl8qhVsFRzwOAYPlM2AWvmsNX+Tlkjsxa3a1k+SYEadjOodVb+Usmz+bq LHm2JGHEnPvDDzUUdaCM2PlAjMq00MF/ah2bpPK/D+nOQSRkLJp0N1nvFWbjnl+Ari EnohuB0idMlXpGF2dQTIRDzCeh2I5k3Z+gVOmoSZAzHVc3N8fnJdvcBIZnA/ThOQ7a UGUnfEJQ2iF+YuWmTPmv+mrNU8etsXXQFxoGTc6P9B+c90lz/9IDZ66S4R150Wj/LD NBPMcrJ58izFbj6bQQqiiQ75uWpXkT8ddrQiZkWC0sfg0vE8hVvfpJLEOSefxrTV6/ YWvfAy9rOkocg== Message-ID: Date: Wed, 22 Jul 2026 00:42:11 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm/slub: prevent pfmemalloc objects from entering the barn To: hu.shengming@zte.com.cn, vbabka@kernel.org Cc: akpm@linux-foundation.org, hao.li@linux.dev, cl@gentwo.org, rientjes@google.com, roman.gushchin@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhang.run@zte.com.cn, cai.qu@zte.com.cn References: <20260721170439864YfrJGliTZWCikCX-HcPzl@zte.com.cn> Content-Language: en-US From: Harry Yoo In-Reply-To: <20260721170439864YfrJGliTZWCikCX-HcPzl@zte.com.cn> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------3tg7DmIrLoZVRKTFmyx5wMJE" X-Rspamd-Queue-Id: A54F920003 X-Stat-Signature: 7ugj8ej8eqiyoucg1zappx16ps5q79e9 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1784648539-210014 X-HE-Meta: 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 xzfr3q9T 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --------------3tg7DmIrLoZVRKTFmyx5wMJE Content-Type: multipart/mixed; boundary="------------sknT1z40q0AKvdHcsxeuBT70"; protected-headers="v1" From: Harry Yoo To: hu.shengming@zte.com.cn, vbabka@kernel.org Cc: akpm@linux-foundation.org, hao.li@linux.dev, cl@gentwo.org, rientjes@google.com, roman.gushchin@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhang.run@zte.com.cn, cai.qu@zte.com.cn Message-ID: Subject: Re: [PATCH v3] mm/slub: prevent pfmemalloc objects from entering the barn References: <20260721170439864YfrJGliTZWCikCX-HcPzl@zte.com.cn> In-Reply-To: <20260721170439864YfrJGliTZWCikCX-HcPzl@zte.com.cn> --------------sknT1z40q0AKvdHcsxeuBT70 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 7/21/26 6:04 PM, hu.shengming@zte.com.cn wrote: > Vlastimil wrote: >> On 7/21/26 09:34, Vlastimil Babka (SUSE) wrote: >>> On 7/21/26 02:45, hu.shengming@zte.com.cn wrote: >>>> From: Shengming Hu >>>> >>>> kmem_cache_return_sheaf() may refill a partially consumed sheaf befo= re >>>> placing it in the barn. Without an explicit restriction, this refill= may >>>> draw objects from pfmemalloc slabs and consume emergency reserves. >>>> >>>> Add __GFP_NOMEMALLOC so that returned sheaves are refilled only from= >>>> non-pfmemalloc slabs. Also add __GFP_NOWARN, as suggested by Hao Li,= >>>> because this refill is a best-effort attempt and failure is acceptab= le.. >>>> If the refill fails, flush and free the sheaf instead. >>>> >>>> Fixes: 3c1ea5c5019f ("slab: sheaf prefilling for guaranteed allocati= ons") >>> >>> Wonder if 1ce20c28eafd ("slab: handle pfmemalloc slabs properly with >>> sheaves") is a better match. Until that commit we just didn't care, a= nd it >>> seems like this is a case that commit missed? >=20 > Agreed, 1ce20c28eafd is a better match. Thanks for catching this. Agreed, thanks! --=20 Cheers, Harry / Hyeonggon --------------sknT1z40q0AKvdHcsxeuBT70-- --------------3tg7DmIrLoZVRKTFmyx5wMJE Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQQQ1ub6gR5ogjaKRmOGXBN6rc5S1gUCal+TUwAKCRCGXBN6rc5S 1pTOAQCaYmEPjb3oa7nqKKas83R+C6PdrboJ4y0zaJuND5YOVwEAmvNtaHdwKxXE oGimas2EKd6CfXp885aX53GRy6KGYwY= =TL4q -----END PGP SIGNATURE----- --------------3tg7DmIrLoZVRKTFmyx5wMJE--