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AHgh+RoKZnHf+TwJJMbuMCrRYaHcWB1AhOHL6Sx+teZJ1O/yBiXMT3MbC6qhnzeFNhZOSAGP+F8MSUJOMpaxAjI=@vger.kernel.org X-Gm-Message-State: AOJu0YxCFMiI+rvDTcUZvnRiEVsZh8MyGpm+B/uRSN4B45IQECGfR+e7 Vf/YlI++bO4sa4nNEWj6zEqMHkrxqznS8bv+Y3u371g1glmsg3rJyIicRwLkOvnL0Bdiq33ZuRH 51WN3hlrFWOaTvwSsC08phAJUtM9f40eRHtnqwl6g X-Gm-Gg: AfdE7clOu3JV6nOyTLI19upUZ+AyliRo267irZtpgVifEmei+JHy/L7WaNh2qvfHmaT L4sShHWk4Y5FGJi78e0L9PVCtNI3xSL9DY9kv4wPIGLNt5PuQLZtRvrO0P5IrI9UGI7WtRQil7s N3mdBPqbJM/twRbmpAqGxOwvLbVJgAITG/a4ke9C6Jdo6I82NlGYiQyDY6L0dsmXGIrZU9u8L1n OhCEPB+LElNWVe373qELlqv6G1zRtHLR6CdA6jLrNEZo9OnqGY2wpH0G/W84ZkyF64WHjh4JdMM sXgYjkWtnEQSE4w= X-Received: by 2002:a05:622a:94:b0:517:6010:7c71 with SMTP id d75a77b69052e-51f7d273976mr9799081cf.4.1784215654893; Thu, 16 Jul 2026 08:27:34 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20260715-b4-objext_split-v1-0-9a49c4ccf4c3@kernel.org> <20260715-b4-objext_split-v1-5-9a49c4ccf4c3@kernel.org> In-Reply-To: From: Suren Baghdasaryan Date: Thu, 16 Jul 2026 08:27:22 -0700 X-Gm-Features: AUfX_my_bAm9pMs_cq2llYbd6SUBazq-pBVNFKSQG59fVdB5bXaPSKf2ohfyPJ4 Message-ID: Subject: Re: [PATCH RFC 05/12] mm/slab: abstract slabobj_ext.objcg access To: "Vlastimil Babka (SUSE)" Cc: Harry Yoo , Hao Li , Shakeel Butt , Alexander Potapenko , Marco Elver , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, Jul 16, 2026 at 6:58=E2=80=AFAM Vlastimil Babka (SUSE) wrote: > > On 7/16/26 03:27, Suren Baghdasaryan wrote: > > On Wed, Jul 15, 2026 at 3:11=E2=80=AFAM Vlastimil Babka (SUSE) > > wrote: > >> --- a/mm/slab.h > >> +++ b/mm/slab.h > >> @@ -555,7 +555,7 @@ static inline bool need_kmalloc_no_objext(void) > >> */ > >> struct slabobj_ext { > >> #ifdef CONFIG_MEMCG > >> - struct obj_cgroup *objcg; > >> + struct obj_cgroup *_objcg; > >> #endif > >> #ifdef CONFIG_MEM_ALLOC_PROFILING > >> union codetag_ref ref; > >> @@ -661,6 +661,13 @@ slab_obj_ext(struct kmem_cache *s, struct slab *s= lab, unsigned long obj_exts, > >> return kasan_reset_tag(obj_ext); > >> } > >> > >> +#ifdef CONFIG_MEMCG > >> +static inline struct obj_cgroup **slab_obj_ext_objcgp(struct slabobj_= ext *obj_ext) > > > > I understand why you need to return obj_cgroup** but maybe instead we > > can have a separate setter function and just return a pointer here? > > Yeah I rewrote it now and it looks better. Thanks! It ended up like this = due > to some previous attempt I made. > > > That would also help catch cases when someone wants to set > > obj_ext._objcg that was optimized away (for that the setter would need > > an additional parameter to identify whether we allocated optimized > > objext vector). > > It would need passing the slab parameter to assert > slab_obj_ext_has_codetag() in debug mode. I don't think it's worth it giv= en > the get/set is only called from few specialized places. Sounds good. > > > > >> +{ > >> + return &obj_ext->_objcg; > >> +} > >> +#endif > >> + > >> int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, > >> gfp_t gfp, unsigned int alloc_flags); > >> > >> diff --git a/mm/slub.c b/mm/slub.c > >> index 5e3f53bcd0d3..48e10198a3ce 100644 > >> --- a/mm/slub.c > >> +++ b/mm/slub.c > >> @@ -2523,7 +2523,7 @@ bool memcg_slab_post_charge(void *p, gfp_t flags= ) > >> if (obj_exts) { > >> get_slab_obj_exts(obj_exts); > >> obj_ext =3D slab_obj_ext(s, slab, obj_exts, p); > >> - if (unlikely(obj_ext->objcg)) { > >> + if (unlikely(*slab_obj_ext_objcgp(obj_ext))) { > >> put_slab_obj_exts(obj_exts); > >> return true; > >> } > >> > >> -- > >> 2.55.0 > >> >