From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750860AbWHTQTr (ORCPT ); Sun, 20 Aug 2006 12:19:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750862AbWHTQTr (ORCPT ); Sun, 20 Aug 2006 12:19:47 -0400 Received: from filfla-vlan276.msk.corbina.net ([213.234.233.49]:48519 "EHLO screens.ru") by vger.kernel.org with ESMTP id S1750860AbWHTQTr (ORCPT ); Sun, 20 Aug 2006 12:19:47 -0400 Date: Mon, 21 Aug 2006 00:43:45 +0400 From: Oleg Nesterov To: Jens Axboe Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: [PATCH] sys_ioprio_set: don't disable irqs Message-ID: <20060820204345.GA5750@oleg> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org It is not good to disable interrupts while traversing all tasks in the system. As I see it, sys_ioprio_get() doesn't need to cli() at all, sys_ioprio_set() does it for cfq_ioc_set_ioprio() which can do it itself. Signed-off-by: Oleg Nesterov --- 2.6.18-rc4/block/cfq-iosched.c~5_setpr 2006-08-09 22:00:44.000000000 +0400 +++ 2.6.18-rc4/block/cfq-iosched.c 2006-08-20 21:23:25.000000000 +0400 @@ -1421,14 +1421,14 @@ static inline void changed_ioprio(struct } /* - * callback from sys_ioprio_set, irqs are disabled + * callback from sys_ioprio_set. */ static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio) { struct cfq_io_context *cic; struct rb_node *n; - spin_lock(&cfq_exit_lock); + spin_lock_irq(&cfq_exit_lock); n = rb_first(&ioc->cic_root); while (n != NULL) { @@ -1438,7 +1438,7 @@ static int cfq_ioc_set_ioprio(struct io_ n = rb_next(n); } - spin_unlock(&cfq_exit_lock); + spin_unlock_irq(&cfq_exit_lock); return 0; } --- 2.6.18-rc4/fs/ioprio.c~5_setpr 2006-08-20 20:16:39.000000000 +0400 +++ 2.6.18-rc4/fs/ioprio.c 2006-08-20 21:21:26.000000000 +0400 @@ -81,7 +81,7 @@ asmlinkage long sys_ioprio_set(int which } ret = -ESRCH; - read_lock_irq(&tasklist_lock); + read_lock(&tasklist_lock); switch (which) { case IOPRIO_WHO_PROCESS: if (!who) @@ -124,7 +124,7 @@ free_uid: ret = -EINVAL; } - read_unlock_irq(&tasklist_lock); + read_unlock(&tasklist_lock); return ret; } @@ -170,7 +170,7 @@ asmlinkage long sys_ioprio_get(int which int ret = -ESRCH; int tmpio; - read_lock_irq(&tasklist_lock); + read_lock(&tasklist_lock); switch (which) { case IOPRIO_WHO_PROCESS: if (!who) @@ -221,7 +221,7 @@ asmlinkage long sys_ioprio_get(int which ret = -EINVAL; } - read_unlock_irq(&tasklist_lock); + read_unlock(&tasklist_lock); return ret; }