From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933113AbYEISAc (ORCPT ); Fri, 9 May 2008 14:00:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755957AbYEISAY (ORCPT ); Fri, 9 May 2008 14:00:24 -0400 Received: from relay1.sgi.com ([192.48.171.29]:45411 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755617AbYEISAX (ORCPT ); Fri, 9 May 2008 14:00:23 -0400 Date: Fri, 9 May 2008 11:00:22 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Peter Zijlstra cc: Olaf Weber , Ingo Molnar , linux-kernel@vger.kernel.org, npiggin@suse.de Subject: Re: Spinlocks waiting with interrupts disabled / preempt disabled. In-Reply-To: <1210355814.13978.255.camel@twins> Message-ID: References: <20080507073017.GJ32195@elte.hu> <1210355814.13978.255.camel@twins> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 9 May 2008, Peter Zijlstra wrote: > > A third solution would be to look at this problem on a case-by-case > > basis. In the case under discussion, there may be other kernel bugs > > that aggravate the problem (it is an old kernel after all) and maybe > > this just means the address_space.tree_lock ought to be replaced with > > something else (though I wouldn't claim to know what). > > That has been done by Nick Piggin, the lockless pagecache work removes > the read side of the tree_lock. When is that going to get merged? find_get_page is still: struct page * find_get_page(struct address_space *mapping, pgoff_t offset) { struct page *page; read_lock_irq(&mapping->tree_lock); page = radix_tree_lookup(&mapping->page_tree, offset); if (page) page_cache_get(page); read_unlock_irq(&mapping->tree_lock); return page; } EXPORT_SYMBOL(find_get_page);