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 IrhZicDR 2zZh8ZYx7jaztt6lvWL7OnA7BeAMDOlxbXa6ThHjEuF5IjdneIhGK6bgZXzXmVprSlJKK1U6+1MwX+ok6IPJM1mY/hlil2OBZj7qdQbPTxH3iiKmMl4TxJ2gdfVcwnAT+NpsY 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 Wed, Feb 04, 2026 at 08:45:19AM +0800, Hao Li wrote: > On Tue, Feb 03, 2026 at 09:32:06PM +0900, Harry Yoo wrote: > > On Tue, Feb 03, 2026 at 07:56:16PM +0800, Hao Li wrote: > > > On Tue, Jan 27, 2026 at 07:31:51PM +0900, Harry Yoo wrote: > > > > diff --git a/mm/slub.c b/mm/slub.c > > > > index ae9af184a18b..0581847e7dac 100644 > > > > --- a/mm/slub.c > > > > +++ b/mm/slub.c > > > > @@ -7676,7 +7676,8 @@ static int calculate_sizes(struct kmem_cache_args *args, struct kmem_cache *s) > > > > */ > > > > aligned_size = ALIGN(size, s->align); > > > > #if defined(CONFIG_SLAB_OBJ_EXT) && defined(CONFIG_64BIT) > > > > - if (aligned_size - size >= sizeof(struct slabobj_ext)) > > > > + if (slab_args_unmergeable(args, s->flags) && > > > > + (aligned_size - size >= sizeof(struct slabobj_ext))) > > > > s->flags |= SLAB_OBJ_EXT_IN_OBJ; > > > > > > Hi Harry, > > > > > > This patch looks reasonable to me. I just noticed a minor point that I > > > wanted to bring up: > > > > > > It seems a bit self-referential that SLAB_NEVER_MERGE already includes > > > SLAB_OBJ_EXT_IN_OBJ, but we're using SLAB_NEVER_MERGE to decide whether to set > > > SLAB_OBJ_EXT_IN_OBJ. > > > > Hi Hao, thanks for bringing it up! > > > > > Do you think it might be helpful to add a comment here for better clarity? > > > > Hmm but I'm not sure what should be clarified here. > > (perhaps because I wrote it). > > > > Checking SLAB_OBJ_EXT_IN_OBJ (as part of SLAB_NEVER_MERGE) before > > setting SLAB_OBJ_EXT_IN_OBJ should be fine (because it's not set before > > we set it), and once you set it, it should prevent merging. > > Yeah, s->flags currently doesn't have SLAB_OBJ_EXT_IN_OBJ, and the functionality > here is totally fine. I just happened to notice this while reading through the > code, and from a semantic perspective, it made me pause for a moment. It looks > like we're checking if s->flags contains SLAB_OBJ_EXT_IN_OBJ (among other flags) > to decide whether we can set SLAB_OBJ_EXT_IN_OBJ. Maybe we could add a small > comment like: "SLAB_OBJ_EXT_IN_OBJ hasn't been set yet here; this is just > checking for other unmergeable reasons." > > Of course, this is just a small thought, it's perfectly fine to leave it as is-I > just thought it might help slightly. I think it's probably okay to leave it as-is for now. But thanks for bringing this up! -- Cheers, Harry / Hyeonggon