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Mon, 07 Apr 2025 09:05:25 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHfWaVdDYJ0191r28pa3c0I5QAq2TX4YfoyI6/S6plMu4jTexyNQOGbQSCGtYlVpcULGOS5sw== X-Received: by 2002:a17:907:7291:b0:ac2:a4ec:46c2 with SMTP id a640c23a62f3a-ac7d1b9c1demr1174821366b.49.1744041924666; Mon, 07 Apr 2025 09:05:24 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ac7bfe5d407sm755045066b.25.2025.04.07.09.05.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Apr 2025 09:05:24 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 1E85D19918CB; Mon, 07 Apr 2025 18:05:23 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Zi Yan , Jesper Dangaard Brouer Cc: "David S. Miller" , Jakub Kicinski , Saeed Mahameed , Leon Romanovsky , Tariq Toukan , Andrew Lunn , Eric Dumazet , Paolo Abeni , Ilias Apalodimas , Simon Horman , Andrew Morton , Mina Almasry , Yonglong Liu , Yunsheng Lin , Pavel Begunkov , Matthew Wilcox , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-rdma@vger.kernel.org, linux-mm@kvack.org, kernel-team Subject: Re: [PATCH net-next v7 1/2] page_pool: Move pp_magic check into helper functions In-Reply-To: <4185FF99-160F-46A9-A5A4-4CA48CC086D1@nvidia.com> References: <20250404-page-pool-track-dma-v7-0-ad34f069bc18@redhat.com> <20250404-page-pool-track-dma-v7-1-ad34f069bc18@redhat.com> <87cydoxsgs.fsf@toke.dk> <87v7rgw1us.fsf@toke.dk> <893B4BFD-1FDA-46DE-82D5-9E5CBDD90068@nvidia.com> <4d35bda2-d032-49db-bb6e-b1d70f10d436@kernel.org> <4185FF99-160F-46A9-A5A4-4CA48CC086D1@nvidia.com> X-Clacks-Overhead: GNU Terry Pratchett Date: Mon, 07 Apr 2025 18:05:23 +0200 Message-ID: <87plhovtx8.fsf@toke.dk> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Zi Yan writes: > On 7 Apr 2025, at 10:43, Jesper Dangaard Brouer wrote: > >> On 07/04/2025 16.15, Zi Yan wrote: >>> On 7 Apr 2025, at 9:36, Zi Yan wrote: >>> >>>> On 7 Apr 2025, at 9:14, Toke H=C3=B8iland-J=C3=B8rgensen wrote: >>>> >>>>> Zi Yan writes: >>>>> >>>>>> Resend to fix my signature. >>>>>> >>>>>> On 7 Apr 2025, at 4:53, Toke H=C3=B8iland-J=C3=B8rgensen wrote: >>>>>> >>>>>>> "Zi Yan" writes: >>>>>>> >>>>>>>> On Fri Apr 4, 2025 at 6:18 AM EDT, Toke H=C3=B8iland-J=C3=B8rgense= n wrote: >>>>>>>>> Since we are about to stash some more information into the pp_mag= ic >>>>>>>>> field, let's move the magic signature checks into a pair of helper >>>>>>>>> functions so it can be changed in one place. >>>>>>>>> >>>>>>>>> Reviewed-by: Mina Almasry >>>>>>>>> Tested-by: Yonglong Liu >>>>>>>>> Acked-by: Jesper Dangaard Brouer >>>>>>>>> Reviewed-by: Ilias Apalodimas >>>>>>>>> Signed-off-by: Toke H=C3=B8iland-J=C3=B8rgensen >>>>>>>>> --- >>>>>>>>> drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c | 4 ++-- >>>>>>>>> include/net/page_pool/types.h | 18 +++++++++= +++++++++ >>>>>>>>> mm/page_alloc.c | 9 +++------ >>>>>>>>> net/core/netmem_priv.h | 5 +++++ >>>>>>>>> net/core/skbuff.c | 16 ++-------= ------- >>>>>>>>> net/core/xdp.c | 4 ++-- >>>>>>>>> 6 files changed, 32 insertions(+), 24 deletions(-) >>>>>>>>> >>>>>>>> >> [...] >> >>>>>>>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >>>>>>>>> index f51aa6051a99867d2d7d8c70aa7c30e523629951..347a3cc2c188f4a9c= ed85e0d198947be7c503526 100644 >>>>>>>>> --- a/mm/page_alloc.c >>>>>>>>> +++ b/mm/page_alloc.c >>>>>>>>> @@ -55,6 +55,7 @@ >>>>>>>>> #include >>>>>>>>> #include >>>>>>>>> #include >>>>>>>>> +#include >>>>>>>>> #include >>>>>>>>> #include "internal.h" >>>>>>>>> #include "shuffle.h" >>>>>>>>> @@ -897,9 +898,7 @@ static inline bool page_expected_state(struct= page *page, >>>>>>>>> #ifdef CONFIG_MEMCG >>>>>>>>> page->memcg_data | >>>>>>>>> #endif >>>>>>>>> -#ifdef CONFIG_PAGE_POOL >>>>>>>>> - ((page->pp_magic & ~0x3UL) =3D=3D PP_SIGNATURE) | >>>>>>>>> -#endif >>>>>>>>> + page_pool_page_is_pp(page) | >>>>>>>>> (page->flags & check_flags))) >>>>>>>>> return false; >>>>>>>>> >>>>>>>>> @@ -926,10 +925,8 @@ static const char *page_bad_reason(struct pa= ge *page, unsigned long flags) >>>>>>>>> if (unlikely(page->memcg_data)) >>>>>>>>> bad_reason =3D "page still charged to cgroup"; >>>>>>>>> #endif >>>>>>>>> -#ifdef CONFIG_PAGE_POOL >>>>>>>>> - if (unlikely((page->pp_magic & ~0x3UL) =3D=3D PP_SIGNATURE)) >>>>>>>>> + if (unlikely(page_pool_page_is_pp(page))) >>>>>>>>> bad_reason =3D "page_pool leak"; >>>>>>>>> -#endif >>>>>>>>> return bad_reason; >>>>>>>>> } >>>>>>>>> >>>>>>>> I wonder if it is OK to make page allocation depend on page_pool f= rom >>>>>>>> net/page_pool. >>>>>>> Why? It's not really a dependency, just a header include with a sta= tic >>>>>>> inline function... >>>>>> The function is checking, not even modifying, an core mm data struct= ure, >>>>>> struct page, which is also used by almost all subsystems. I do not g= et >>>>>> why the function is in net subsystem. >>>>> Well, because it's using details of the PP definitions, so keeping it >>>>> there nicely encapsulates things. I mean, that's the whole point of >>>>> defining a wrapper function - encapsulating the logic =F0=9F=99=82 >>>>> >>>>>>>> Would linux/mm.h be a better place for page_pool_page_is_pp()? >>>>>>> That would require moving all the definitions introduced in patch 2, >>>>>>> which I don't think is appropriate. > > The patch at the bottom moves page_pool_page_is_pp() to mm.h and compiles. > The macros and the function use mm=E2=80=99s page->pp_magic, so I am not = sure > why it is appropriate, especially the user of the macros, net/core/page_p= ool.c, > has already included mm.h. Well, I kinda considered those details page_pool-internal. But okay, I can move them if you prefer to have them in mm.h. -Toke