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b=JYMDLAPIlnGDCSLBNWLAx73Dyjpl3FQ1FyElE4UAZCi0GlccwDiBVINdBVS3Bs5OY F/6z6VGnNuxR94PeS40d0KDlddWiw/hiCFcxGuON3usR/zxnwpoQ8TdmjJJN4Q2QXu HMoBSAbw+qFYO+eQhoRGGbPgDToer86yFVpeWaBJHBvA6CIFRa1+WSgPA4iTN6mayx AsylWJ6DNUJcKiztzWcNL7Nbcp6g4QLG7yj5aUCqxovYzyvxfhjcHPq+Nmr+2Yvc93 af91GIxf+ZohcO+uyeLIaa7NHL9V7Txzzd34rWzNxEbGCwCyvgYrnzGZOeKS/GjXJ+ UeiVKqOzarHfA== Date: Mon, 19 Oct 2026 18:58:15 +0100 From: Harry Yoo To: Konstantin Khorenko Cc: Andrew Morton , Dave Chinner , Qi Zheng , Roman Gushchin , Muchun Song , Johannes Weiner , Michal Hocko , Shakeel Butt , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH v3] mm/shrinker: allocate shrinker_info_unit from a dedicated kmem_cache Message-ID: References: <20261019-vstor-144715-shrinker_info_unit-kmem_cache-v3-1-0fb061e09bf4@virtuozzo.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261019-vstor-144715-shrinker_info_unit-kmem_cache-v3-1-0fb061e09bf4@virtuozzo.com> X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: B290B40009 X-Stat-Signature: d8bezkpxcpixn8go47gpcdgfw8q6ibgu X-Rspam-User: X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1792432698-596305 X-HE-Meta: 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 lhKpsOEV 5JZvN7qewk2+ugcFlBBH5+L1lL6jZ+5giPllwzntQKYgWTFGC4deAh72siMPhXdqi+QoVRJ/YuZedsbB5YuKzZ/EQ/XbRA19sH5p7pXeb328assskjaJgoGiYrQLRT15M3M+WdNwMuK+j7z4RmN+CN95+dWwWTTJUZd0SPBEVp+T0vVz8b1eQpgdBsROxIKXito4TkBKeKy89ROkUhkCaD+/ERJTCbdy6JgdyeHUpgNuJ43uisuLgLhv0eIrTWdhkwizS8Jf+/xXFRJEvndfCPwuALbZeorDEloGGmdz5jah6gK+DFbhdz4lNJJh7jczYpHwuQOdw5fYE76VDBq8gUCKMiTJG7lfWs9iN+3J9GtmFz/SicstcGqGOls+yzT02xIdJYfN+4alyY/GiknLfaAtSEqLmJC6ugrilizwFxHlB6o2LzX1wUsY7xA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Mon, Oct 19, 2026 at 06:11:44PM +0200, Konstantin Khorenko wrote: > shrinker_info_unit holds BITS_PER_LONG atomic_long_t of deferred work > plus a one-word bitmap, 520 bytes on 64-bit. kzalloc_node() takes it > from kmalloc-1k, so almost half of every unit is padding. > > Allocate the units from a cache of their own, sized to the unit. The > cache is not cache-line aligned: the counters of a unit already share > cache lines between shrinkers, and aligning the unit would only keep > neighbouring units off each other's boundary line, at the cost of part > of the saving. > > Suggested-by: Andrew Morton > Assisted-by: LLM > Signed-off-by: Konstantin Khorenko > --- Looks good to me, Reviewed-by: Harry Yoo (Meta) -- Cheers, Harry / Hyeonggon