Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947905AbbGaVj2 (ORCPT ); Fri, 31 Jul 2015 17:39:28 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46397 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754307AbbGaTwh (ORCPT ); Fri, 31 Jul 2015 15:52:37 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Justin M. Forbes" , Ming Lei , Tejun Heo , Jens Axboe Subject: [PATCH 4.1 121/267] block: loop: avoiding too many pending per work I/O Date: Fri, 31 Jul 2015 12:39:32 -0700 Message-Id: <20150731194005.717372852@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150731194001.933895871@linuxfoundation.org> References: <20150731194001.933895871@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1932 Lines: 58 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ming Lei commit 4d4e41aef9429872ea3b105e83426941f7185ab6 upstream. If there are too many pending per work I/O, too many high priority work thread can be generated so that system performance can be effected. This patch limits the max_active parameter of workqueue as 16. This patch fixes Fedora 22 live booting performance regression when it is booted from squashfs over dm based on loop, and looks the following reasons are related with the problem: - not like other filesyststems(such as ext4), squashfs is a bit special, and I observed that increasing I/O jobs to access file in squashfs only improve I/O performance a little, but it can make big difference for ext4 - nested loop: both squashfs.img and ext3fs.img are mounted as loop block, and ext3fs.img is inside the squashfs - during booting, lots of tasks may run concurrently Fixes: b5dd2f6047ca108001328aac0e8588edd15f1778 Cc: Justin M. Forbes Signed-off-by: Ming Lei Acked-by: Tejun Heo Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- drivers/block/loop.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -725,7 +725,7 @@ static int loop_set_fd(struct loop_devic goto out_putf; error = -ENOMEM; lo->wq = alloc_workqueue("kloopd%d", - WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 0, + WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 16, lo->lo_number); if (!lo->wq) goto out_putf; -- 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/