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[84.247.152.65]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2d75988cb5dsm2170415ad.64.2026.08.27.22.30.05 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 27 Aug 2026 22:30:15 -0700 (PDT) From: Lian Wang To: Kairui Song via B4 Relay Cc: linux-mm@kvack.org, Andrew Morton , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Shakeel Butt , Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Chris Li , Baolin Wang , Ridong Chen , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Yu Zhao , Zi Yan , Qi Zheng , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Kairui Song , Kairui Song Subject: Re: [PATCH v3 5/6] mm/mglru: use explicit tier range in read_ctrl_pos() Date: Fri, 28 Aug 2026 13:29:28 +0800 Message-ID: <20260828052949.52874-1-lianux.mm@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260826-mglru-flags-cleanup-v3-5-d9f1c75549c8@tencent.com> References: <20260826-mglru-flags-cleanup-v3-0-d9f1c75549c8@tencent.com> <20260826-mglru-flags-cleanup-v3-5-d9f1c75549c8@tencent.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 3879F1A0007 X-Stat-Signature: 1ceri4m9utd47gqqesg6ghkmhziyokxx X-Rspam-User: X-HE-Tag: 1787895017-319804 X-HE-Meta: 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 FE1GJC5G 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Kairui, > Replace it with explicit (tier_min, tier_max) parameters using a > closed [tier_min, tier_max] interval While touching read_ctrl_pos(), would it make sense to add: lockdep_assert_held(&lruvec->lru_lock); All current callers run under the lruvec lock. read_ctrl_pos() derives the history slot from min_seq and combines avg_refaulted/avg_total and protected with the atomic counters, while reset_ctrl_pos() rotates and clears that state under the same lock and already has this assertion. Adding the assertion here would document the snapshot contract and catch a future lockless caller before it can observe fields from different history epochs. If I missed an existing lockless caller, or if this is intentionally a best-effort snapshot, please ignore this suggestion. Thanks, Lian