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Tue, 01 Sep 2026 03:59:43 -0700 (PDT) Received: from celestia ([2402:1980:9c5:2de5:8b4e:3f3c:b637:4ca5]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3990d499811sm6303184a91.10.2026.09.01.03.59.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Sep 2026 03:59:43 -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] mm/damon/core: fix quota could not be set to zero Date: Tue, 1 Sep 2026 18:59:51 +0800 Message-ID: <20260901105951.106246-1-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 becomes error. However, damos_set_effective_quota() unconditionally clamps the quota to min_region_sz, preventing the quota from ever reaching zero. Fix this by skip the min_region_sz clamping when esz is already zero so that the temporal tuner's intent is respected. Fixes: 8bbde987c2b8 ("mm/damon/core: disallow time-quota setting zero esz") Cc: # v7.1.x Signed-off-by: Liew Rui Yan --- mm/damon/core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/damon/core.c b/mm/damon/core.c index 53cf32f1d515..0258769b8727 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -3114,7 +3114,8 @@ static void damos_set_effective_quota(struct damon_ctx *ctx, struct damos *s) else throughput = PAGE_SIZE * 1024; esz = min(throughput * quota->ms, esz); - esz = max(ctx->min_region_sz, esz); + if (esz) + esz = max(ctx->min_region_sz, esz); } if (quota->sz && quota->sz < esz) -- 2.55.0