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b=ovoH7RXYEpV1zAeJEinykeprmqVgXdFWDCWcpQLn6fgXzXhY3UlUqtf4JtXqz2cLS FJo4v0tTeZSl3vT990E1U7UFovkIirYQ91CSoD03B/BMvpc4AmrLiOd69kN7d9oYcY q7PCes77Wwa/1snwRzYun4Ui4XCOGC7hNu4UnjqgXFiAbQxhMUCPgPfemHYbm0Ebix jIWqIYNM/4KH8zIc8aLMZ70l55Nk2PlSmlrx9/u3GL25Z5EORRnyKUOLQKfObPmhZw rw54uozu9lDajgan0qRSkHYZzpAXoKR7+M4Dp7fahnMc87fpr91QBFuaxx5/g5XiQz Np+FVrD/wtYIQ== Message-ID: <80afa9ac-ed48-438e-a18d-87aa8dff23c4@kernel.org> Date: Thu, 11 Jun 2026 13:57:35 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 05/16] mm/slab: introduce alloc_flags and SLAB_ALLOC_TRYLOCK To: "Vlastimil Babka (SUSE)" Cc: Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Suren Baghdasaryan , Alexei Starovoitov , Andrew Morton , Johannes Weiner , Michal Hocko , Shakeel Butt , Alexander Potapenko , Marco Elver , Dmitry Vyukov , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org References: <20260610-slab_alloc_flags-v2-0-7190909db118@kernel.org> <20260610-slab_alloc_flags-v2-5-7190909db118@kernel.org> Content-Language: en-US From: Harry Yoo In-Reply-To: <20260610-slab_alloc_flags-v2-5-7190909db118@kernel.org> Content-Type: multipart/signed; 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boundary="------------lp6v3Rt10tV79iXTePM8CevI"; protected-headers="v1" From: Harry Yoo To: "Vlastimil Babka (SUSE)" Cc: Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Suren Baghdasaryan , Alexei Starovoitov , Andrew Morton , Johannes Weiner , Michal Hocko , Shakeel Butt , Alexander Potapenko , Marco Elver , Dmitry Vyukov , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Message-ID: <80afa9ac-ed48-438e-a18d-87aa8dff23c4@kernel.org> Subject: Re: [PATCH v2 05/16] mm/slab: introduce alloc_flags and SLAB_ALLOC_TRYLOCK References: <20260610-slab_alloc_flags-v2-0-7190909db118@kernel.org> <20260610-slab_alloc_flags-v2-5-7190909db118@kernel.org> In-Reply-To: <20260610-slab_alloc_flags-v2-5-7190909db118@kernel.org> --------------lp6v3Rt10tV79iXTePM8CevI Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 6/11/26 12:40 AM, Vlastimil Babka (SUSE) wrote: > Similarly to the page allocators, introduce slab-allocator specific > alloc flags that internally control allocation behavior in addition to > gfp_flags, without occupying the limited gfp flags space. >=20 > Introduce the first flag SLAB_ALLOC_TRYLOCK that behaves similarly to > page allocator's ALLOC_TRYLOCK and will be used to reimplement > kmalloc_nolock()'s "!allow_spin" behavior. That currently relies on > gfpflags_allow_spinning() and thus the lack of both __GFP_RECLAIM flags= , > importantly __GFP_KSWAPD_RECLAIM. This can give false-positive results > e.g. in early boot with a restricted gfp_allowed_mask. >=20 > Also introduce alloc_flags_allow_spinning() to replace the usage of > gfpflags_allow_spinning(). >=20 > Start using alloc_flags and the new check first in alloc_from_pcs() and= > __pcs_replace_empty_main(). This means some slab allocations that were > falsely treated as kmalloc_nolock() due to their gfp flags will now hav= e > higher chances of succeed, and this will further increase with followup= > changes. >=20 > Remove a WARN_ON_ONCE() from refill_objects() as it's now legitimate to= > reach it from a slab allocation that's not _nolock() and yet lacks > __GFP_KSWAPD_RECLAIM for other reasons. > > Signed-off-by: Vlastimil Babka (SUSE) > --- Reviewed-by: Harry Yoo (Oracle) --=20 Cheers, Harry / Hyeonggon --------------lp6v3Rt10tV79iXTePM8CevI-- --------------zrehXDAjlbhFhdK5H063TW73 Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQQQ1ub6gR5ogjaKRmOGXBN6rc5S1gUCaipAQAAKCRCGXBN6rc5S 1liHAP93IfCcefH4oC5NqVaMFx2nH2a1RYl/VCXiuzTBFVHwygEAzw865aRaoheL 3Yd7pXejrNcoaV9GzniJGj0nDB+/Xgk= =IIMK -----END PGP SIGNATURE----- --------------zrehXDAjlbhFhdK5H063TW73--