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Fri, 26 May 2023 20:55:58 -0700 (PDT) MIME-Version: 1.0 References: <20230527103126.398267-1-linmiaohe@huawei.com> In-Reply-To: <20230527103126.398267-1-linmiaohe@huawei.com> From: Yosry Ahmed Date: Fri, 26 May 2023 20:55:22 -0700 Message-ID: Subject: Re: [PATCH] memcg: remove unused mem_cgroup_from_obj() To: Miaohe Lin Cc: hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com, akpm@linux-foundation.org, muchun.song@linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 97D4E4000D X-Stat-Signature: kihcj3c3tiy8p3f9xs4ineyaa5h4oemc X-HE-Tag: 1685159760-566558 X-HE-Meta: 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 lquKjZGm MemQYuTB04md5o80rpc8kkpiIDBGO1Mj3eftKnMc+spF77QEL735xcf1hhQ63bXjC+5ok6qhGoGX7OXLdjaii2NjWtk1SbKg8Lc3wBYsdB/xFjvQ9iYMERhnbs7xC+kOq2vYO6brCio//HPTCMQ3/V2waT0UD92DPNw5ztWpdXIFo0fOjuK0mbC/KMo5/3T1jBPJIh36Sh8mSNHXj7sZOPBlIyK4SH6omCjRyjcWIeIYu/xAomW5gXBDwvtsOtc6U4fGzXrmM1dPeLSDhI+AgSLdpaMCOHO4B/5/N7g8+TIsMu3ZHrVjP0xrB7VrQFa3rMyIl 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: On Fri, May 26, 2023 at 7:40=E2=80=AFPM Miaohe Lin w= rote: > > The function mem_cgroup_from_obj() is not used anymore. Remove it and > clean up relevant comments. > > Signed-off-by: Miaohe Lin > --- > include/linux/memcontrol.h | 6 ------ > mm/memcontrol.c | 31 ------------------------------- > 2 files changed, 37 deletions(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 00a88cf947e1..ce8c2355ed9f 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -1813,7 +1813,6 @@ static inline int memcg_kmem_id(struct mem_cgroup *= memcg) > return memcg ? memcg->kmemcg_id : -1; > } > > -struct mem_cgroup *mem_cgroup_from_obj(void *p); > struct mem_cgroup *mem_cgroup_from_slab_obj(void *p); > > static inline void count_objcg_event(struct obj_cgroup *objcg, > @@ -1876,11 +1875,6 @@ static inline int memcg_kmem_id(struct mem_cgroup = *memcg) > return -1; > } > > -static inline struct mem_cgroup *mem_cgroup_from_obj(void *p) > -{ > - return NULL; > -} > - > static inline struct mem_cgroup *mem_cgroup_from_slab_obj(void *p) > { > return NULL; > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 6a3d4ce87b8a..532b29c9a0fe 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2972,37 +2972,6 @@ struct mem_cgroup *mem_cgroup_from_obj_folio(struc= t folio *folio, void *p) > /* > * Returns a pointer to the memory cgroup to which the kernel object is = charged. > * > - * A passed kernel object can be a slab object, vmalloc object or a gene= ric > - * kernel page, so different mechanisms for getting the memory cgroup po= inter > - * should be used. > - * > - * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the= caller > - * can not know for sure how the kernel object is implemented. > - * mem_cgroup_from_obj() can be safely used in such cases. > - * > - * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lo= ck(), > - * cgroup_mutex, etc. > - */ > -struct mem_cgroup *mem_cgroup_from_obj(void *p) > -{ > - struct folio *folio; > - > - if (mem_cgroup_disabled()) > - return NULL; > - > - if (unlikely(is_vmalloc_addr(p))) > - folio =3D page_folio(vmalloc_to_page(p)); > - else > - folio =3D virt_to_folio(p); > - > - return mem_cgroup_from_obj_folio(folio, p); > -} > - > -/* > - * Returns a pointer to the memory cgroup to which the kernel object is = charged. > - * Similar to mem_cgroup_from_obj(), but faster and not suitable for obj= ects, > - * allocated using vmalloc(). Perhaps keep the line about not being suitable for objects allocated using vmalloc()? To be fair it's obvious from the function name, but I am guessing whoever added it did for a reason. I don't feel strongly either way, LGTM. I can't see any references in Linus's tree or mm-unstable. Reviewed-by: Yosry Ahmed > - * > * A passed kernel object must be a slab object or a generic kernel page= . > * > * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lo= ck(), > -- > 2.27.0 >