From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751022AbdAPRcX (ORCPT ); Mon, 16 Jan 2017 12:32:23 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:36066 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750858AbdAPRcV (ORCPT ); Mon, 16 Jan 2017 12:32:21 -0500 Date: Mon, 16 Jan 2017 09:32:20 -0800 From: Christoph Hellwig To: Jaegeuk Kim Cc: Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, axboe@kernel.dk Subject: Re: [PATCH 5/6] f2fs: add a kernel thread to issue discard commands asynchronously Message-ID: <20170116173220.GA2199@infradead.org> References: <20170112224407.54026-1-jaegeuk@kernel.org> <20170112224407.54026-5-jaegeuk@kernel.org> <20170113080159.GB31777@infradead.org> <20170113191211.GB1301@jaegeuk.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170113191211.GB1301@jaegeuk.local> User-Agent: Mutt/1.7.1 (2016-10-04) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 13, 2017 at 11:12:11AM -0800, Jaegeuk Kim wrote: > Previously, I've done to issue discard bios asynchronously. But the problem that > I've got is that was not enough. When testing nvme SSD with noop IO scheduler, > submit_bio() was blocked at every 8 async discard bios, resulting in very slow > checkpoint process which blocks most of other FS operations. Where does it block? Are you running out of request? What driver is this on top of?