From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.240 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793883177; b=Da745pHsc7iOAWdc1zp7Fs1XDIyzB1JhU0dbV85H58kI/+mtZNU12g/2ISzbW+9l8VLH Ut7bBE9G37VO3OscKQzzhXXU7Zi1/ljvZUdkU01pcZSvUrdpmenc6kBObi7HfjEB3IuoG 2DgVJ5eRSKqMFViHqJct2NOnQ1cLXPmfcOOmrlb5kMwFyrszAEf3X3ojDqvvosjbrY02e 7gUIIFyqcyvFH0UuBmKwiCrzTbSNvEKz8N/f/298zWcJryoeUwjvEe7JPrENBs6cD9MpH L+pAL9PH97vmH9r+lY/s3vQjMtJXfRFGL+ked9dceoEey3R5esuD5+zu4+4YUvUVt2A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793883177; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:Date:Message-Id: X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=U7QPnMltm0NUA1TBoFVEGMv8tP5BZSUYF1lBRbJpUqE=; b=DI7X2Y7V6hhr0/WVggxuLLJIwnUoAxh8cezEhhkGqzNr7poCJkHJCPFqOpIdJc6nM8a8 hn5Q8znkV4ZZ7D5Cn+weQV8Eb2/Hdha6m4hWX+q4JiS9FX2eEmNhHkdTyLaUu4yzhLXQW 3W7bm5U/64aNbBk+/phooQFISIiI4JnjjsqJrGMwIC9GZYopXv/JkgG0qsYzz1zqRQXJk R/Co78hbO4zYibQ7gNPCY2KwhO3lEKhEKg4zwEqRv8oKWFw9grU/oA7OjEi62l5KjxIlR Fl81WUVQMXo3Jn9fYuWEIegjt0YlJ6c2nRPuK9cj7Q83viws9gJAib8z0zgTNhYkkvg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=OWOkAeAS; arc=none smtp.remote-ip=95.215.58.240 Received: from mta1.migadu.com (out-240.mta1.migadu.com [95.215.58.240]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 28089606D834 for ; Thu, 5 Nov 2026 12:52:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 28089606D834 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, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=OWOkAeAS X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=P5EDvk6rF/qCnD0K9efR1giZB/efgKEHgWhKG6KkDcY=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793883175; v=1; x=1794487975; b=OWOkAeASOOYzab0z0xD+L69GxFgOK8SO1sE3RARiQVshHf0r2C13Rii5U9HJUBtQAh+jmzL2 AFIWZfTXqFonE9Dhc50H4+U8s6NHKJV7cAM0onkwI2CJuRn0ZuH9QjpNHNXaUi7+cx1vBwr6dZz nXKQ+BoKGFhiGfbz1TE8FFog= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id d32cdb94a89149b2; Thu, 05 Nov 2026 12:52:55 +0000 X-Mizu-Trace-ID: d32cdb94a89149b2 X-Migadu-Flow: FLOW_OUT From: Ridong Chen To: Waiman Long , Tejun Heo , Johannes Weiner , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Shuah Khan Cc: Ridong Chen , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Sashiko , Guopeng Zhang , Chen Ridong , Ridong Chen Subject: [PATCH 2/4] cpuset: add early empty cpumask check in partition_xcpus_add/del Date: Thu, 5 Nov 2026 20:52:13 +0800 Message-Id: <20261105125215.2205892-3-ridong.chen@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20261105125215.2205892-1-ridong.chen@linux.dev> References: <20261105125215.2205892-1-ridong.chen@linux.dev> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chen Ridong Add a check for an empty cpumask at the start of partition_xcpus_add() and partition_xcpus_del(). This allows the functions to return early, avoiding unnecessary computation when there is no work to be done. With these changes, partition_xcpus_add() and partition_xcpus_del() can be called even if xcpus is empty. The caller no longer needs to check whether xcpus is empty, eliminating many conditional statements. Signed-off-by: Chen Ridong Reviewed-by: Guopeng Zhang Signed-off-by: Ridong Chen --- kernel/cgroup/cpuset.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index bc16fd1b1c5e..68b82dabbf38 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1315,10 +1315,13 @@ static void partition_xcpus_add(int new_prs, struct cpuset *parent, { WARN_ON_ONCE(new_prs < 0); lockdep_assert_held(&callback_lock); + + if (cpumask_empty(xcpus)) + return; + if (!parent) parent = &top_cpuset; - if (parent == &top_cpuset) cpumask_or(subpartitions_cpus, subpartitions_cpus, xcpus); @@ -1342,6 +1345,10 @@ static void partition_xcpus_del(int old_prs, struct cpuset *parent, { WARN_ON_ONCE(old_prs < 0); lockdep_assert_held(&callback_lock); + + if (cpumask_empty(xcpus)) + return; + if (!parent) parent = &top_cpuset; -- 2.34.1