From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.133]:59932 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751626AbeFDIrk (ORCPT ); Mon, 4 Jun 2018 04:47:40 -0400 Date: Mon, 4 Jun 2018 01:47:39 -0700 From: Christoph Hellwig To: Miklos Szeredi Cc: linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 05/39] vfs: optionally don't account file in nr_files Message-ID: <20180604084739.GD11333@infradead.org> References: <20180529144339.16538-1-mszeredi@redhat.com> <20180529144339.16538-6-mszeredi@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180529144339.16538-6-mszeredi@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, May 29, 2018 at 04:43:05PM +0200, Miklos Szeredi wrote: > Stacking file operations in overlay will store an extra open file for each > overlay file opened. > > The overhead is just that of "struct file" which is about 256bytes, because > overlay already pins an extra dentry and inode when the file is open, which > add up to a much larger overhead. But that overhead is exactly what nr_files accounts for, so this looks bogus to me.