Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754570Ab0DIKyi (ORCPT ); Fri, 9 Apr 2010 06:54:38 -0400 Received: from ns2.intersolute.de ([193.110.43.67]:39292 "EHLO ns2.intersolute.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751927Ab0DIKyf (ORCPT ); Fri, 9 Apr 2010 06:54:35 -0400 Message-ID: <4BBF0762.8040505@lumino.de> Date: Fri, 09 Apr 2010 12:54:26 +0200 From: Michael Schnell User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.9) Gecko/20100317 SUSE/3.0.4-2.3 Thunderbird/3.0.4 MIME-Version: 1.0 CC: linux-kernel , nios2-dev Subject: Re: atomic RAM ? References: <4BBD86A5.5030109@lumino.de> <20100408.051453.231567150.davem@davemloft.net> <4BBDCC6E.3060702@lumino.de> <201004081615.01151.arnd@arndb.de> In-Reply-To: <201004081615.01151.arnd@arndb.de> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 659 Lines: 15 On 04/08/2010 04:15 PM, Arnd Bergmann wrote: > /* returns one if we got the lock, zero if someone else holds it */ > bool hashlock_addr(volatile void *addr); > I don't see how (to do FUTEX) a hashlock can be implemented in a way that we stay in user mode when locking it and - if it's already locked - we do a Kernel call for waiting on it being unlocked by another thread. (This is what FUTEX does.) -Michael -- 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/