Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752818AbaFIGWO (ORCPT ); Mon, 9 Jun 2014 02:22:14 -0400 Received: from mail-wg0-f41.google.com ([74.125.82.41]:40859 "EHLO mail-wg0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750980AbaFIGWL (ORCPT ); Mon, 9 Jun 2014 02:22:11 -0400 Message-ID: <1402294928.6316.38.camel@marge.simpson.net> Subject: Re: [RFC PATCH] rt/aio: fix rcu garbage collection might_sleep() splat From: Mike Galbraith To: Lai Jiangshan Cc: RT , LKML , Sebastian Andrzej Siewior , Steven Rostedt , Thomas Gleixner , "Paul E. McKenney" Date: Mon, 09 Jun 2014 08:22:08 +0200 In-Reply-To: <1402283822.5195.3.camel@marge.simpson.net> References: <1402216538.31630.7.camel@marge.simpson.net> <5395172E.4010007@cn.fujitsu.com> <1402283822.5195.3.camel@marge.simpson.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2014-06-09 at 05:17 +0200, Mike Galbraith wrote: > On Mon, 2014-06-09 at 10:08 +0800, Lai Jiangshan wrote: > > Hi, rt-people > > > > I don't think it is the correct direction. > > Yup, it's a band-aid, ergo RFC. Making aio play by the rules is safe. Another option is to bend the rules up a little. With the below, ltp aio-stress testcases haven't yet griped or exploded either.. which somehow isn't quite as comforting as "is safe" :) --- fs/aio.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/aio.c +++ b/fs/aio.c @@ -509,7 +509,9 @@ static void free_ioctx_reqs(struct percp struct kioctx *ctx = container_of(ref, struct kioctx, reqs); INIT_WORK(&ctx->free_work, free_ioctx); + preempt_enable_rt(); schedule_work(&ctx->free_work); + preempt_disable_rt(); } /* @@ -522,7 +524,9 @@ static void free_ioctx_users(struct perc struct kioctx *ctx = container_of(ref, struct kioctx, users); struct kiocb *req; + preempt_enable_rt(); spin_lock_irq(&ctx->ctx_lock); + local_irq_disable_rt(); while (!list_empty(&ctx->active_reqs)) { req = list_first_entry(&ctx->active_reqs, @@ -536,6 +540,8 @@ static void free_ioctx_users(struct perc percpu_ref_kill(&ctx->reqs); percpu_ref_put(&ctx->reqs); + preempt_disable_rt(); + local_irq_enable_rt(); } static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm) -- 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/