Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932286Ab2K1Txz (ORCPT ); Wed, 28 Nov 2012 14:53:55 -0500 Received: from mail-wi0-f174.google.com ([209.85.212.174]:49868 "EHLO mail-wi0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755589Ab2K1Txw (ORCPT ); Wed, 28 Nov 2012 14:53:52 -0500 MIME-Version: 1.0 In-Reply-To: <20121128194314.GF4939@ZenIV.linux.org.uk> References: <50B46E05.70906@kernel.dk> <50B4B313.3030707@kernel.dk> <50B5CC5A.8060607@kernel.dk> <20121128194314.GF4939@ZenIV.linux.org.uk> From: Linus Torvalds Date: Wed, 28 Nov 2012 11:53:31 -0800 X-Google-Sender-Auth: _PllgQYRuL5ZjeOk2Lks8MLDnnI Message-ID: Subject: Re: [PATCH] Introduce a method to catch mmap_region (was: Recent kernel "mount" slow) To: Al Viro Cc: Mikulas Patocka , Jens Axboe , Jeff Chua , Lai Jiangshan , Jan Kara , lkml , linux-fsdevel Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1137 Lines: 24 On Wed, Nov 28, 2012 at 11:43 AM, Al Viro wrote: > Have a > private vm_operations - a copy of generic_file_vm_ops with ->open()/->close() > added to it. That sounds more reasonable. However, I suspect the *most* reasonable thing to do is to just remove the whole damn thing. We really shouldn't care about mmap. If somebody does a mmap on a block device, and somebody else then changes the block size, why-ever should we bother to go through any contortions at *all* to make that kind of insane behavior do anything sane at all. Just let people mmap things. Then just let the normal page cache invalidation work right. In fact, it is entirely possible that we could/should just not even invalidate the page cache at all, just make sure that the buffer heads attached to any pages get disconnected. No? Linus -- 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/