From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by vger.rutgers.edu via listexpand id ; Sat, 15 May 1999 00:31:18 -0400 Received: by vger.rutgers.edu id ; Fri, 14 May 1999 16:03:15 -0400 Received: from hqinbh1.ms.com ([205.228.12.71]:49310 "EHLO hqinbh1.ms.com") by vger.rutgers.edu with ESMTP id ; Fri, 14 May 1999 09:49:47 -0400 Message-ID: <373C34F8.5DE45537@ms.com> Date: Fri, 14 May 1999 15:36:40 +0100 From: Jan-Simon Pendry X-Mailer: Mozilla 4.5 [en] (X11; I; Linux 2.3.0 i586) X-Accept-Language: en MIME-Version: 1.0 To: Jakub Jelinek CC: Marcelo Tosatti , linux-kernel@vger.rutgers.edu Subject: Re: [PATCH][2.3.0] Read-write locks instead semaphores on UTS structures References: <373B07EF.58664F9B@ms.com> <19990514123456.R3172@mff.cuni.cz> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-linux-kernel@vger.rutgers.edu X-UIDL: 926742673.455407.3615 Jakub Jelinek wrote > > Huh? His patch uses read-write locks and not normal spin-locks, so I don't > understand what you find wrong on it. read-write locks are a variant of spin locks. you can deadlock the system if you go to sleep holding holding any spin lock. the only exception is the kernel lock which has special code to deal with it in schedule(). ideally the spinlock code (spin_lock and read_lock et al) would have debug versions that counted how many locks were held (in some per-cpu data structure), and have schedule() check that this number was zero before putting the process to sleep. jan-simon. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/