From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D3A18C2B9F7 for ; Mon, 24 May 2021 14:11:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B6C9E610CE for ; Mon, 24 May 2021 14:11:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233029AbhEXOM4 (ORCPT ); Mon, 24 May 2021 10:12:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:45918 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233004AbhEXOMv (ORCPT ); Mon, 24 May 2021 10:12:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1621865481; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=XrgScrtgPE6h0yjFQjkRNhNAavrRYvrma6AaGeqjrVc=; b=YirQvvSzv2AId6c8/vh1jsyENZpp9zmxMhREPUM3VMvkt3PcSVTwFrIzzgJ4mkNe2ViPBx 0H9/T4PI26/8m7jmJs6kpB0BQGIjTDjUGXXroFf/BwqjMPG0ds2y6q7858oZjs13z/yD97 eIPO3bvcbaJ3BO7OLe1cedFCsrlZXfI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-331-lh9f0pMyNxGBhr0E5-DRCQ-1; Mon, 24 May 2021 10:11:19 -0400 X-MC-Unique: lh9f0pMyNxGBhr0E5-DRCQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4AF84107B78A; Mon, 24 May 2021 14:11:18 +0000 (UTC) Received: from T590 (ovpn-12-30.pek2.redhat.com [10.72.12.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2E2D35C701; Mon, 24 May 2021 14:11:15 +0000 (UTC) Date: Mon, 24 May 2021 22:11:10 +0800 From: Ming Lei To: Brian Foster Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v3 1/3] iomap: resched ioend completion when in non-atomic context Message-ID: References: <20210517171722.1266878-1-bfoster@redhat.com> <20210517171722.1266878-2-bfoster@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, May 24, 2021 at 07:57:48AM -0400, Brian Foster wrote: > On Sat, May 22, 2021 at 03:45:11PM +0800, Ming Lei wrote: > > On Mon, May 17, 2021 at 01:17:20PM -0400, Brian Foster wrote: > > > The iomap ioend mechanism has the ability to construct very large, > > > contiguous bios and/or bio chains. This has been reported to lead to > > > > BTW, it is actually wrong to complete a large bio chains in > > iomap_finish_ioend(), which may risk in bio allocation deadlock, cause > > bio_alloc_bioset() relies on bio submission to make forward progress. But > > it becomes not true when all chained bios are freed just after the whole > > ioend is done since all chained bios(except for the one embedded in ioend) > > are allocated from same bioset(fs_bio_set). > > > > Interesting. Do you have a reproducer (or error report) for this? Is it No, but the theory has been applied for long time. > addressed by the next patch, or are further changes required? Your patchset can't address the issue. Thanks, Ming