Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754650AbbDPSJ7 (ORCPT ); Thu, 16 Apr 2015 14:09:59 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:37689 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753426AbbDPSJu (ORCPT ); Thu, 16 Apr 2015 14:09:50 -0400 Date: Thu, 16 Apr 2015 19:09:32 +0100 From: Al Viro To: Mateusz Guzik Cc: Andrew Morton , "Paul E. McKenney" , Yann Droneaud , Konstantin Khlebnikov , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] fs: use a sequence counter instead of file_lock in fd_install Message-ID: <20150416180932.GW889@ZenIV.linux.org.uk> References: <20150416121628.GA20615@mguzik> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150416121628.GA20615@mguzik> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 892 Lines: 19 On Thu, Apr 16, 2015 at 02:16:31PM +0200, Mateusz Guzik wrote: > @@ -165,8 +165,10 @@ static int expand_fdtable(struct files_struct *files, int nr) > cur_fdt = files_fdtable(files); > if (nr >= cur_fdt->max_fds) { > /* Continue as planned */ > + write_seqcount_begin(&files->fdt_seqcount); > copy_fdtable(new_fdt, cur_fdt); > rcu_assign_pointer(files->fdt, new_fdt); > + write_seqcount_end(&files->fdt_seqcount); > if (cur_fdt != &files->fdtab) > call_rcu(&cur_fdt->rcu, free_fdtable_rcu); Interesting. AFAICS, your test doesn't step anywhere near that path, does it? So basically you never hit the retries during that... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/