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bh=+IOYzbq22lhYIf1iXAGWkCEwZrUSQpgR/aOknVb4vnM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GZ9DFD1HCeOqE9xfWczRsB/Jf8bnqdi6VhHAyJPn52H77HPYsj9JTrPKSty0M2Kk9 0UL6R9253A8E9Br970ftJaIx8QNUQOOuwmGdFK4G2/v83ZRt4sfZMJEvZUl8+bXR6M qZ3w4yBwNfMPmRQilj2boskC6V+LcHz+iswV3QK8p+EdHpjoPotT+3I3d+6ghAMHeX A2mHtaVE8+YMuoss7QXfcfx9f4v5fSxNkqf1GlzfBoF46/uRnutowkv4Kx8kHxoBqJ pvr6YxvJYZFIoRGhklUa+6cVySPOxdDQ15BW9/9+joPEm4GH0nnhmMc3VGOlR0nQxp spC+8u8Q+Z7Ww== From: SJ Park To: Cc: SJ Park , stable@vger.kernel.org, Andrew Morton , Ravi Jonnalagadda , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH v1.3 3/4] mm/damon/core: copy nid for eligible_mem_bp damos quota goal commit Date: Fri, 28 Aug 2026 11:36:47 -0700 Message-ID: <20260828183649.71192-4-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260828183649.71192-1-sj@kernel.org> References: <20260828183649.71192-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Stat-Signature: p7ujjq5pq9q8pbxoxhofqapr1wea1bt7 X-Rspamd-Queue-Id: 4108A40002 X-Rspamd-Server: rspam06 X-HE-Tag: 1787942220-948805 X-HE-Meta: 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 IIXNx/ml sUbX/wxqpTu1mIlSNEhL+1dqlZ1fOKxnWhewWzI+g/BQOy9OiWw/Oc5RU8YBlVCiYDi2w+R1CH6fSr2nVcgh/PZ3oaHPZ0PBiZ4Z+0z9cckCXdQFoFRc5k/Y+vGdas0qCeLcpHkreBvKi0P6xlEzzt1K/BZFTOfE7PX2VrWYQCAtgT4OJzrTuCOeIWWFvXo1o4Oz6S8DaxlXC/8TMo0u9oi8t6BqIimXvUGZejfLDM8whu9no6+n/v10VitAjD9jhi1U2gMKklq4IDBzApzMYKfEY3taAb0dtoI86844rffS3txX7mX7q7hS3i3vFjpgVabblcw4DN3bU6SByv/m4teanNxyqnamHrBKpxCdii/3+CnZOFct5P7OXvomSuGOg2RUlZ6a3FERiqGAk+fKt7INLkvfhp99WbyJ9 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: damos_commit_quota_goal_union() is not updating the ->nid union field when the goal metric is DAMOS_QUITA_NODE_ELIGIBLE_MEM_BP. Hence, if a DAMOS quota goal of the type is online committed in a way that it will reuse other quota goal's memory space, the new goal will work with a garbage nid value. As a result, the DAMOS scheme can show unexpected aggressiveness. Do the update. The user impact is not catastrophic. No leak or crash happens. Doing the quota goal online commit that can reproduce the issue is expected to be not common. This issue was not found by real users but the AI review. That said, the issue can reliably be reproduced. This issue was discovered [1] by Sashiko. [1] https://lore.kkernel.org/20260827045035.94611-1-sj@kernel.org Fixes: 9138e27a3bc3 ("mm/damon: add node_eligible_mem_bp goal metric") Cc: # 7.2.x Signed-off-by: SJ Park --- mm/damon/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index 39605e64dabf2..b3f8bea774c2d 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -1136,6 +1136,9 @@ static void damos_commit_quota_goal_union( dst->nid = src->nid; dst->memcg_id = src->memcg_id; break; + case DAMOS_QUOTA_NODE_ELIGIBLE_MEM_BP: + dst->nid = src->nid; + break; default: break; } -- 2.47.3