From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751771AbdECDZL (ORCPT ); Tue, 2 May 2017 23:25:11 -0400 Received: from mail-ua0-f193.google.com ([209.85.217.193]:35630 "EHLO mail-ua0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750819AbdECDYx (ORCPT ); Tue, 2 May 2017 23:24:53 -0400 MIME-Version: 1.0 In-Reply-To: <87wp9yq462.fsf@notabene.neil.brown.name> References: <149369628671.5146.4865312503373040039.stgit@noble> <149369654434.5146.15331164625586213889.stgit@noble> <87wp9yq462.fsf@notabene.neil.brown.name> From: Ming Lei Date: Wed, 3 May 2017 11:24:51 +0800 Message-ID: Subject: Re: [PATCH 03/13 V2] blk: make the bioset rescue_workqueue optional. To: NeilBrown Cc: Jens Axboe , linux-block , Linux Kernel Mailing List , Christoph Hellwig Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 3, 2017 at 6:34 AM, NeilBrown wrote: > From 09017acf74ec4df674b78ca66f0924187f10d8a4 Mon Sep 17 00:00:00 2001 > From: NeilBrown > Date: Fri, 10 Mar 2017 13:59:50 +1100 > Subject: [PATCH] blk: make the bioset rescue_workqueue optional. > > This patch converts bioset_create() to not create a workqueue by > default, so alloctions will never trigger punt_bios_to_rescuer(). It > also introduces a new flag BIOSET_NEED_RESCUER() which tells > bioset_create() to preserve the old behavior. > > All callers of bioset_create() that are inside block device drivers, > are given the BIOSET_NEED_RESCUER(). > > biosets used by filesystems or other top-level users do not > need rescuing as the bio can never be queued behind other > bios. This includes fs_bio_set, blkdev_dio_pool, > btrfs_bioset, xfs_ioend_bioset, and one allocated by > target_core_iblock.c. > > biosets used by md/raid do not need rescuing as > their usage was recently audited and revised to never > risk deadlock. > > It is hoped that most, if not all, of the remaining biosets > can end up being the non-rescued version. > > Reviewed-by: Christoph Hellwig > Credit-to: Ming Lei (minor fixes) > Signed-off-by: NeilBrown Reviewed-by: Ming Lei Thanks, Ming