From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta0.migadu.com (out-181.mta0.migadu.com [91.218.175.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C9FB714A8B for ; Tue, 2 Jun 2026 04:35:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780374909; cv=none; b=AbAq/nrKAwh4Du1wwwipn3rMx+SJl1QqJq+S2fCoFwEpcO913Tej7eMuG6XeFq51K6Ky0El9PnbgLqCxb9PSx8j+SDaM/EztzcH4parMYUNn//SURy768IuANTAc9Z5KzOMKHTftVvRp7wiiDSyBrNr6GePMJf6MqERFcPNQw9I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780374909; c=relaxed/simple; bh=AjUrIUN8kJ+V9mftkXkX7P50uAZ8iF3w3J3ZF+ZMY7g=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=jI99S3HJ5oO7SQx0z2IKLFjMQCbLOWC8sbe0/o09AhrrjNXzHcv1o/7tNPTGx0Jj1SJmQ315ZoyPIDKKW6MR6q63b2URqfxu2J7Qn8expKXORec9w5naNjI6bwaU3C1DVtlr1Rsg5psmJPzzasSahxs38FM+LxgkYIWsyVmTbKg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=HZ+Ve0Mr; arc=none smtp.client-ip=91.218.175.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="HZ+Ve0Mr" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1780374904; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=NgwzeQZYBkXu7U3Vz6FCT3bGFgzALNC0m/GPi7PoAp4=; b=HZ+Ve0MrPDFwnU/cx5DmPS2k6/sGmTO0W/b3GRkYbj77VOarf2rpNjDKEg8UAOg9dAH/Gu JD5P6kAiy0GMeCbgqbwCi5CiPopgiF3Um7JCF70Iz9FPRueWQ/DrMKyCfFX4U16fFsY0KV nohz4Rxi1ky2NiAvslzJpJjlWtgCEjA= From: Lance Yang To: akpm@linux-foundation.org Cc: david@kernel.org, ljs@kernel.org, shakeel.butt@linux.dev, mhocko@kernel.org, david@fromorbit.com, roman.gushchin@linux.dev, muchun.song@linux.dev, qi.zheng@linux.dev, yosry.ahmed@linux.dev, ziy@nvidia.com, liam@infradead.org, usama.arif@linux.dev, kas@kernel.org, vbabka@kernel.org, ryncsn@gmail.com, zaslonko@linux.ibm.com, gor@linux.ibm.com, wangkefeng.wang@huawei.com, baolin.wang@linux.alibaba.com, baohua@kernel.org, dev.jain@arm.com, npache@redhat.com, ryan.roberts@arm.com, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Lance Yang Subject: [PATCH 1/1] mm/thp: clear deferred split shrinker bits when queues drain Date: Tue, 2 Jun 2026 12:34:53 +0800 Message-ID: <20260602043453.67597-1-lance.yang@linux.dev> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Lance Yang deferred_split_count() returns the raw list_lru count. When the per-memcg, per-node list is empty, that count is 0. That skips scanning, but it does not tell memcg reclaim that the shrinker is empty. shrink_slab_memcg() only clears the memcg shrinker bit when the count callback reports SHRINK_EMPTY. Return SHRINK_EMPTY for an empty deferred split list, so the bit can be cleared once the queue has drained. Signed-off-by: Lance Yang --- mm/huge_memory.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 72f6caf0fec6..62d598290c3b 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -4397,7 +4397,10 @@ void deferred_split_folio(struct folio *folio, bool partially_mapped) static unsigned long deferred_split_count(struct shrinker *shrink, struct shrink_control *sc) { - return list_lru_shrink_count(&deferred_split_lru, sc); + unsigned long count; + + count = list_lru_shrink_count(&deferred_split_lru, sc); + return count ?: SHRINK_EMPTY; } static bool thp_underused(struct folio *folio) -- 2.49.0