From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 1CDA92264A9 for ; Sun, 23 Nov 2025 18:58:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763924320; cv=none; b=DtmkcbFjIg/yQhqXMwYbGw4ahlOxmI0gtdsEdSKem2oeNNpL30nRqDxDyLSXM8jjlWy1fvaB6+rrTdBiv5UKxUnv8hI/hNua0prpRQrxyAjL+/QDJkftO5niUCuTh2RIXQ3D4Zmnz2TkCmeL733eT48uDDuge+cbhkrAZDbUB4E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763924320; c=relaxed/simple; bh=u9SXG8Fem6J9joLJXermltA19lP4o2HINfJtM6ofb6g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZWrSwe2knyrap/nUQVtNSsouRI4vHcST3cAx/JfWLO9/ks1US2yyta6A8D3ktaUzaryJOMTfmkbkmlBzxyWB1qGSHoUUVz6XBYVOgrvFCf7EXrnXMOULBwShGtsh6mylbTDujALZPAd2F7NWT3Nvkf7pn+MHz7ZWIQIXWB8vXpM= 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=T2s4Sxl9; arc=none smtp.client-ip=170.10.129.124 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="T2s4Sxl9" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1763924316; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=wGBGXV63GWONBhSXcOYRfuWB1hafcWHebaEyXH0Age8=; b=T2s4Sxl9q2vAhkyiJlP4GPn6PNqEUJVbCNv7UlbUY1NIhjMH7A/m0tl3+MJOxz2Cb0URU2 kpXvZDWXtRjyzdaGYVTMwbgapfU4KppQP+0YrkjfXWoUziY8qQHK02LsKQrrLf20B5/hNp gyRl7dy8rF4lbL1HCM6tHd5Z9YOgEmI= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-91-PsLgnA6uOli0lSIaSWPAWQ-1; Sun, 23 Nov 2025 13:58:35 -0500 X-MC-Unique: PsLgnA6uOli0lSIaSWPAWQ-1 X-Mimecast-MFC-AGG-ID: PsLgnA6uOli0lSIaSWPAWQ_1763924314 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 17B8B180057A; Sun, 23 Nov 2025 18:58:34 +0000 (UTC) Received: from fedora (unknown [10.44.32.8]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 048881956056; Sun, 23 Nov 2025 18:58:31 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Sun, 23 Nov 2025 19:58:33 +0100 (CET) Date: Sun, 23 Nov 2025 19:58:30 +0100 From: Oleg Nesterov To: Mateusz Guzik Cc: brauner@kernel.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org Subject: Re: [PATCH 2/3] ns: pad refcount Message-ID: References: <20251123063054.3502938-1-mjguzik@gmail.com> <20251123063054.3502938-3-mjguzik@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251123063054.3502938-3-mjguzik@gmail.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 On 11/23, Mateusz Guzik wrote: > > struct ns_common { > + struct { > + refcount_t __ns_ref; /* do not use directly */ > + } ____cacheline_aligned_in_smp; Cough... stupid question. Why not just refcount_t __ns_ref ____cacheline_aligned_in_smp; ? why do we need the anonymous struct? Oleg.