From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 1EEAE3B2326 for ; Sat, 28 Feb 2026 18:28:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772303294; cv=none; b=pV2qqP7fFqs6vjEtcQMNdkjC7KEz3Ln5bhq6YwcptXyUtwiMrlmQDzIEXqtmj3W3Bg/iVYgRx/bfxoUOEvQByTcnGbvq6CpRN5eNEW97emdtTdr1/l5FzcRl0RmaK5+R3O5nDyxdAdDnIFTityWAT5i2HIzJ3ALYX5SbkjLLMxQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772303294; c=relaxed/simple; bh=xSHZE2a4FmsJnbM6miwzdJ5cI4Xsdj1vy/YMTH+O/nY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=ju+NzOB1u+tx301xIenWcAJ/6IH1Kd+oPM/6XONgJ15ulfKtggLv2jnY4IbPK8QqFlMrKAszBAz1QHUxi5UHJI1MWim/e6QgV1qm87Jo5e1BcT9nL+4R7BIz5VdN+hUGXnX7SmyJKSULmJXJJ43+zjqG8XRWX05Y89E5vr3Ot1g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=QoH/JI34; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QoH/JI34" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1772303292; 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=a/hFCs81cNsxu+qlQAKknDKpc+SOHunIa7+2foWYf/4=; b=QoH/JI34rXsypSpUM+D8kusV7687ZdoyN5WCtltXC74RbN11n8XKbsWbAn4w8rxVeJU+6A xPdI/4cQuiFsahvc8m0YPfYt1W7y68Ud1poYwQHiohZFqxrbFkzN9Mv4Ws1tjGOfzmjgK7 omd24AuUmNHmnr3TIYhr+X57z7AWN0E= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-462-Q46BqXX7MMa8chVasbN7_w-1; Sat, 28 Feb 2026 13:28:08 -0500 X-MC-Unique: Q46BqXX7MMa8chVasbN7_w-1 X-Mimecast-MFC-AGG-ID: Q46BqXX7MMa8chVasbN7_w_1772303287 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1E1E6195609E; Sat, 28 Feb 2026 18:28:07 +0000 (UTC) Received: from llong-thinkpadp16vgen1.westford.csb (unknown [10.2.16.6]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id C0F071800351; Sat, 28 Feb 2026 18:28:03 +0000 (UTC) From: Waiman Long To: Paul Moore , Eric Paris , Christian Brauner , Al Viro , Jan Kara Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, audit@vger.kernel.org, Richard Guy Briggs , Ricardo Robaina , Waiman Long Subject: [PATCH v4 0/2] fs, audit: Avoid excessive dput/dget in audit_context setup and reset paths Date: Sat, 28 Feb 2026 13:27:55 -0500 Message-ID: <20260228182757.90528-1-longman@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 v4: - Add ack and review tags - Simplify put_fs_pwd_pool() in patch 1 as suggested by Paul Moore v3: - https://lore.kernel.org/lkml/20260206201918.1988344-1-longman@redhat.com/ When the audit subsystem is enabled, it can do a lot of get_fs_pwd() calls to get references to fs->pwd and then releasing those references back with path_put() later. That may cause a lot of spinlock contention on a single pwd's dentry lock because of the constant changes to the reference count when there are many processes on the same working directory actively doing open/close system calls. This can cause noticeable performance regresssion when compared with the case where the audit subsystem is turned off especially on systems with a lot of CPUs which is becoming more common these days. This patch series aim to avoid this type of performance regression caused by audit by adding a new set of fs_struct helpers to reduce unncessary path_get() and path_put() calls and the audit code is modified to use these new helpers. Waiman Long (2): fs: Add a pool of extra fs->pwd references to fs_struct audit: Use the new {get,put}_fs_pwd_pool() APIs to get/put pwd references fs/fs_struct.c | 26 +++++++++++++++++++++----- fs/namespace.c | 8 ++++++++ include/linux/fs_struct.h | 28 +++++++++++++++++++++++++++- kernel/auditsc.c | 7 +++++-- 4 files changed, 61 insertions(+), 8 deletions(-) -- 2.53.0