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From: Muchun Song In-Reply-To: <20260522011908.1669332-4-shakeel.butt@linux.dev> Date: Fri, 22 May 2026 14:27:23 +0800 Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Roman Gushchin , Qi Zheng , Alexandre Ghiti , Joshua Hahn , Harry Yoo , Meta kernel team , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel test robot Content-Transfer-Encoding: quoted-printable Message-Id: <7706EBA4-B9A1-4E33-AE96-9D351D91EBE2@linux.dev> References: <20260522011908.1669332-1-shakeel.butt@linux.dev> <20260522011908.1669332-4-shakeel.butt@linux.dev> To: Shakeel Butt X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 9A9A0A000B X-Stat-Signature: 7rttok443bhhdd8i68rxbgg3gm43qyus X-HE-Tag: 1779431292-21535 X-HE-Meta: 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 7WzNd30a /6R3B16mXLThpFo1cfVwK2qQSvyhqqhBtOjea6S1R7efwGTmQ6sLVKfcnt3pj5Hvm4/1RROrGphPdZDGKou5Grc/EB9fKE9W39/el2Whff0WyqpBdF9s2sz/Nd4sFZzNMZdHiY4cJDJ+82wFTS6n7EDsDZojijj4uJR3WCCC+L3m9ghsvgEL/VkRDTzee+tnAlr13xb9+NU+KEAolcESozdKH61SGnqDu2QYcE1xWjtcYX15MzeSmrrHsPxHHXdKJTc00r0MrVYkhF1Db2G1ACyTuAhcl3hH0lVG9epYvo4434ou4gcVieYQjm9iOz0D+BwEraL7YgyJYJdK45YAyNWHobEg4enB0f1fxWjBinFvNyJ8/YcZacYsvWNjSaEEX0Cq93khfVfptmAA5OkhwR4rAzg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > On May 22, 2026, at 09:19, Shakeel Butt = wrote: >=20 > Currently struct obj_stock_pcp stores cached slab stats in 'int' which > is 4 bytes per counter on 64-bit machines. Switch them to int16_t to > shrink the cached metadata. >=20 > The existing PAGE_SIZE flush in __account_obj_stock() bounds *bytes at > PAGE_SIZE on 4KiB and 16KiB page archs, well within int16_t. On 64KiB > pages PAGE_SIZE is well above S16_MAX so that flush never fires, and a > sufficiently long run of accumulations would overflow the cache. Add > an explicit S16_MAX guard before each add: when the next add would > push abs(*bytes) past S16_MAX, fold the cached value into @nr and > flush directly via mod_objcg_mlstate() before the accumulation. >=20 > Fixes: 01b9da291c49 ("mm: memcontrol: convert objcg to be per-memcg = per-node type") > Tested-by: kernel test robot > Signed-off-by: Shakeel Butt > Reviewed-by: Harry Yoo (Oracle) Acked-by: Muchun Song Thanks.=