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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23709C433EF for ; Mon, 18 Oct 2021 15:04:50 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8924460E0C for ; Mon, 18 Oct 2021 15:04:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8924460E0C Authentication-Results: mail.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634569488; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=o6cMmKTm/xTp8awcQahR0ySM1vhSOKIz9MTb+j+iDYE=; b=YsfQK7tvY1jY+enq95pWjQUWy2bnTfwUi0gS55DAdtygBYnpyoHmRzjaD85Gg1KWTI3BUf 5qDBtav9Gid3I1nHc8NVbYDxCj6YEu/+RourgTxiQQ1PVeHAMQpzn0JA03CHTnKBakZ3JS C5wALjJ7vG9Oo7K80L2AGeZekZnzbX8= 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-591-BQhOav6jP1qcvv6ayZvSOQ-1; Mon, 18 Oct 2021 11:04:45 -0400 X-MC-Unique: BQhOav6jP1qcvv6ayZvSOQ-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 6099DCC626; Mon, 18 Oct 2021 15:04:36 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 582121803E; Mon, 18 Oct 2021 15:04:33 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id AEFEA4EA2A; Mon, 18 Oct 2021 15:04:23 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 19IF4LRG029685 for ; Mon, 18 Oct 2021 11:04:21 -0400 Received: by smtp.corp.redhat.com (Postfix) id C723F4180; Mon, 18 Oct 2021 15:04:20 +0000 (UTC) Received: from redhat.com (unknown [10.15.80.136]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2F9FB60657; Mon, 18 Oct 2021 15:04:20 +0000 (UTC) Date: Mon, 18 Oct 2021 10:04:18 -0500 From: David Teigland To: Martin Wilck Message-ID: <20211018150418.GA3917@redhat.com> References: <20210607214835.GB8181@redhat.com> <20210608122901.o7nw3v56kt756acu@alatyr-rpi.brq.redhat.com> <20210909194417.GC19437@redhat.com> <20210927100032.xczilyd5263b4ohk@alatyr-rpi.brq.redhat.com> <20210927153822.GA4779@redhat.com> <20210929213952.ws2qpmedaajs5wlx@alatyr-rpi.brq.redhat.com> <20210930155542.GB32174@redhat.com> <418b2bd497a3a4cd76840b3cceb1955ba7e9ba01.camel@suse.com> MIME-Version: 1.0 In-Reply-To: <418b2bd497a3a4cd76840b3cceb1955ba7e9ba01.camel@suse.com> User-Agent: Mutt/1.8.3 (2017-05-23) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-loop: linux-lvm@redhat.com Cc: "zkabelac@redhat.com" , "bmarzins@redhat.com" , "prajnoha@redhat.com" , "linux-lvm@redhat.com" , Heming Zhao Subject: Re: [linux-lvm] Discussion: performance issue on event activation mode X-BeenThere: linux-lvm@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-lvm-bounces@redhat.com Errors-To: linux-lvm-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=linux-lvm-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Mon, Oct 18, 2021 at 06:24:49AM +0000, Martin Wilck wrote: > I'd like to second Peter here, "RUN" is in general less fragile than > "IMPORT{PROGRAM}". You should use IMPORT{PROGRAM}" if and only if > > - the invoked program can work with incomplete udev state of a device > (the progrem should not try to access the device via > libudev, it should rather get properties either from sysfs or the > uevent's environment variables) > - you need the result or the output of the program in order to proceed > with rules processing. Those are both true in this case. I can't say I like it either, but udev rules force hacky solutions on us. I began trying to use RUN several months ago and I think I gave up trying to find a way to pass values from the RUN program back into the udev rule (possibly by writing values to a temp file and then doing IMPORT{file}). The udev rule needs the name of the VG to activate, and that name comes from the pvscan. For an even uglier form of this, see the equivalent I wrote for dracut: https://github.com/dracutdevs/dracut/pull/1567/files The latest version of the hybrid service+event activation is here https://sourceware.org/git/?p=lvm2.git;a=shortlog;h=refs/heads/dev-dct-activation-switch-7 I've made it simple to edit lvm.conf to switch between: - activation from fixed services only - activation from events only - activation from fixes services first, then from events There are sure to be tradeoffs, we know that many concurrent activations from events are slow, and fixed services which are more serialized could be delayed from slow devices. I'm still undecided on the best default setting, i.e. which will work best for most people, and would welcome any thoughts or relevant experience. Dave _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://listman.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/