From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.118 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794052896; b=xybpKVSLZfhrRrIcRF6wiAyCkzufsD13aij9wtw2LwfPZ+scdM8ujtYfT8RawWGCywZp Tpx3c5HVzKFWP5bcoo0omzR2GChsqCp/k+u6pxeG/tXRQ1vPurvQO+/iUmZtVxYjOhCjG n/+MrBunry7fhr8B76mnR8kaiEjjRCYXwqI3gZ1I455ee20rxlrfzoIqqz/gxgi9YHlcC c63Pwe/HV7fJEHXr/vnCi3/8AXWkoTgrBWRMhmzG71BhMLYLWIfFsjT2M1vJ5BlS5V9+8 Q8CpoymEgIFJ1bd7M+rNxOuVF2TupBWWErOAPK/fJKbjpthOL5JEf3CmwFBNxe5hf6g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794052896; 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=wElNnZ4hdxfiRXy4j7gbm0Wmawl6S57V0Z2kUwgAtHE=; b=UzQ5XB3wkUpaAsJYM9SdtzTecLZWDQ3fAsSq3rqUEhN495G6uoHz0BaF7nTqft0P6iuV Y6D5DLzbr6zxDuBzzQtU/XnVEcTtJBb6PxrjT1K4QFBIso3LNo348xb0sFlMy1LxyEvsT cN40CFNxenhAxSpDfZqYEW6PcEG6r1QilDwFyA27HcPkVCHZSYF9IeaiqFGEnSdlM2sDJ k8UC9mDNJAAi1T199dAx05fVd72iW7vlmTKoyHWytPgQQwNZCthYGn8drOFlnl//Nqe9O i4hg87pWH3aS+z073TeMNJqoEn7/DrBQikXhd4A84SlJpdIRG3+nBy1QRsdQLbL3uKA== 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=qN7RNtVN; arc=none smtp.remote-ip=91.218.175.118 Received: from mta0.migadu.com (out-118.mta0.migadu.com [91.218.175.118]) (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 1CE62606A32C for ; Sat, 7 Nov 2026 12:01:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 1CE62606A32C 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=qN7RNtVN X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=t6znqfsrDtxXSf05RcmdumzvabWUDmUMM6r+znXO2jw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794052894; v=1; x=1794657694; b=qN7RNtVNfFAGGNNtW6wp+M6EkYK9oUZ2dFzOuG7Tbg3TbvuFgiTChIpH9OwELixoh8lPmOJO OkdOATVGlof2yFJWJD4JLWwle45iOFE7equyl56qe2LryWaLD+5wvpTc0jG3mDwoHHSDfT4cfFi rCQ0z+2uxVT91Z4vuAXCI3Gc= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 206b7a00877809c6; Sat, 07 Nov 2026 12:01:34 +0000 X-Mizu-Trace-ID: 206b7a00877809c6 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 , Chen Ridong , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Sashiko , Guopeng Zhang , Ridong Chen Subject: [PATCH v3 2/4] cpuset: add early empty cpumask check in partition_xcpus_add/del Date: Sat, 7 Nov 2026 20:00:58 +0800 Message-Id: <20261107120100.3587595-3-ridong.chen@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20261107120100.3587595-1-ridong.chen@linux.dev> References: <20261107120100.3587595-1-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 Reviewed-by: Waiman Long 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 cf38e8708ddd..85e5b529d144 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