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Wed, 02 Sep 2026 01:20:41 -0700 (PDT) Received: from celestia.taila51cc2.ts.net ([2402:1980:9c5:2de5:8b4e:3f3c:b637:4ca5]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-39ae3c72584sm4119404a91.17.2026.09.02.01.20.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Sep 2026 01:20:41 -0700 (PDT) From: Liew Rui Yan To: SJ Park Cc: Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Liew Rui Yan , stable@vger.kernel.org Subject: [PATCH v2] mm/damon/core: allow esz to be set to zero Date: Wed, 2 Sep 2026 16:20:50 +0800 Message-ID: <20260902082050.19566-1-aethernet65535@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When the temporal quota goal tuner determines that the goal has been achieved (score >= 10000), it sets esz_bp to zero so that the effective quota (esz) becomes zero. However, damos_set_effective_quota() clamps the quota to min_region_sz, preventing the quota from ever reaching zero. Fix this by adding a check for zero esz_bp. Fixes: 8bbde987c2b8 ("mm/damon/core: disallow time-quota setting zero esz") Cc: # v7.1.x Signed-off-by: Liew Rui Yan --- Changes from v1: - v1: https://lore.kernel.org/damon/20260901105951.106246-1-aethernet65535@gmail.com - Changed implementation. The initial solution skipped the min_region_sz clamping when esz was already zero. However, this would revert the fix from commit 8bbde987c2b8 and cause a regression. This revision fixes the issue by adding a specific check for a zero esz_bp. - Changed patch title, original title: fix quota could not be set to zero --- mm/damon/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/damon/core.c b/mm/damon/core.c index e13a154aa4b9..8e3ded1a2cf6 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -3133,6 +3133,9 @@ static void damos_set_effective_quota(struct damon_ctx *ctx, struct damos *s) if (quota->sz && quota->sz < esz) esz = quota->sz; + if (!quota->esz_bp) + esz = 0; + quota->esz = esz; } -- 2.55.0