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Wed, 27 Aug 2025 23:59:04 -0700 (PDT) MIME-Version: 1.0 References: <20250826071948.2618-1-laoar.shao@gmail.com> <20250826071948.2618-3-laoar.shao@gmail.com> In-Reply-To: From: Yafang Shao Date: Thu, 28 Aug 2025 14:58:28 +0800 X-Gm-Features: Ac12FXxzOOTe1natEd0mMCAsPZpFJWP7A30MXtoADcSt0CwP8hYi3Z3hSqrAKo0 Message-ID: Subject: Re: [PATCH v6 mm-new 02/10] mm: thp: add a new kfunc bpf_mm_get_mem_cgroup() To: Shakeel Butt Cc: akpm@linux-foundation.org, david@redhat.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, hannes@cmpxchg.org, usamaarif642@gmail.com, gutierrez.asier@huawei-partners.com, willy@infradead.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, ameryhung@gmail.com, rientjes@google.com, corbet@lwn.net, bpf@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 539AF4000B X-Stat-Signature: wenm181nyx9fro6p7yeddk1zs77nf36a X-Rspam-User: X-HE-Tag: 1756364345-513636 X-HE-Meta: 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 KgRCxEhG LprkLevYVl9h1iKAgpYV4qj3cKIs5ttPKcQoEYZ9YvqYmzHzB1Znq3vEOtrvNehWfiSiQt16iVGP4frKv6yWCMN3NmHMl2D6hzewCmQR4YRgPHft0pbaHV2eSVnk1lhK4bVCo X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Aug 28, 2025 at 4:46=E2=80=AFAM Shakeel Butt wrote: > > On Tue, Aug 26, 2025 at 03:19:40PM +0800, Yafang Shao wrote: > > We will utilize this new kfunc bpf_mm_get_mem_cgroup() to retrieve the > > associated mem_cgroup from the given @mm. The obtained mem_cgroup must > > be released by calling bpf_put_mem_cgroup() as a paired operation. > > > > Signed-off-by: Yafang Shao > > --- > > mm/bpf_thp.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++++- > > 1 file changed, 50 insertions(+), 1 deletion(-) > > > > diff --git a/mm/bpf_thp.c b/mm/bpf_thp.c > > index fbff3b1bb988..b757e8f425fd 100644 > > --- a/mm/bpf_thp.c > > +++ b/mm/bpf_thp.c > > @@ -175,10 +175,59 @@ static struct bpf_struct_ops bpf_bpf_thp_ops =3D = { > > .name =3D "bpf_thp_ops", > > }; > > > > +__bpf_kfunc_start_defs(); > > + > > +/** > > + * bpf_mm_get_mem_cgroup - Get the memory cgroup associated with a mm_= struct. > > + * @mm: The mm_struct to query > > + * > > + * The obtained mem_cgroup must be released by calling bpf_put_mem_cgr= oup(). > > + * > > + * Return: The associated mem_cgroup on success, or NULL on failure. N= ote that > > + * this function depends on CONFIG_MEMCG being enabled - it will alway= s return > > + * NULL if CONFIG_MEMCG is not configured. > > + */ > > +__bpf_kfunc struct mem_cgroup *bpf_mm_get_mem_cgroup(struct mm_struct = *mm) > > +{ > > + return get_mem_cgroup_from_mm(mm); > > +} > > + > > +/** > > + * bpf_put_mem_cgroup - Release a memory cgroup obtained from bpf_mm_g= et_mem_cgroup() > > + * @memcg: The memory cgroup to release > > + */ > > +__bpf_kfunc void bpf_put_mem_cgroup(struct mem_cgroup *memcg) > > +{ > > +#ifdef CONFIG_MEMCG > > + if (!memcg) > > + return; > > + css_put(&memcg->css); > > +#endif > > Just use mem_cgroup_put() here. i will change it and thanks for the clarification. --=20 Regards Yafang