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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A036C433EF for ; Tue, 31 May 2022 15:17:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345558AbiEaPRZ (ORCPT ); Tue, 31 May 2022 11:17:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44252 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344803AbiEaPRY (ORCPT ); Tue, 31 May 2022 11:17:24 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E63B72662 for ; Tue, 31 May 2022 08:17:23 -0700 (PDT) Date: Tue, 31 May 2022 17:17:17 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1654010240; 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=ol3kdkkk49nmiEiLcm/7rDa+qO3nNFafIE0Bw/6OUk0=; b=t3FrJiRoPbZh2x554/Emq/9bEyUFR5JJhmQp5hzkLW/cdG5uzx3h/02s6mtp0mcZZYRZ0W p5qXU9RRoxleqaWeUONt/M0ediJvZg8my07GH1xlnstz5YEjYUgZ8ZDT1wnwpAFKPIvlv/ GSNDwEoPMUAIKMKjDyXrqgOf+apz0HDYN6YQVN9JkNqDOPXZGNM+86z8+Vd5myaHEca9cG aTqtOsdTScNEDHO49aSDcK55vkoKJO8W9bDQq9DlqaNYGOvcNvmOrAd8vKTBGLAQJQVKDv Jrk/a1Lz/6mPvC8kz5B8FmOJjLu98QhRs885YPKv7SHyUaN1b4VWYIFi6zxNhw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1654010240; 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=ol3kdkkk49nmiEiLcm/7rDa+qO3nNFafIE0Bw/6OUk0=; b=YYbj+yTX4y7TUNOYU7j8BjN8o8PqLSZQQcfwmfXspxPCCJjW9qIBS/JLHYr7UmgX8OYjR9 C8oPL3gQGNsuWjDA== From: Sebastian Andrzej Siewior To: John Garry Cc: Davidlohr Bueso , linux-scsi@vger.kernel.org, martin.petersen@oracle.com, ejb@linux.ibm.com, tglx@linutronix.de Subject: Re: [PATCH 01/10] scsi/mvsas: Kill CONFIG_SCSI_MVSAS_TASKLET Message-ID: References: <20220530231512.9729-1-dave@stgolabs.net> <20220530231512.9729-2-dave@stgolabs.net> <17747966-ea44-ebe5-3d79-df7c33b6a16e@huawei.com> <20220531145231.opypdzrlrg23ihil@offworld> <5d28e848-0b9d-2aaa-e00e-7888342d25a7@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5d28e848-0b9d-2aaa-e00e-7888342d25a7@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 2022-05-31 16:12:05 [+0100], John Garry wrote: > On 31/05/2022 15:52, Davidlohr Bueso wrote: > > On Tue, 31 May 2022, John Garry wrote: > > > Question: Can there be any good reason to do this? > > > > Removing tasklets altogether, albeit perhaps a pipe dream. > > Sorry, maybe I was not clear, but I was just asking if there was a good > reason to disable interrupts at source while handling the interrupt, and not > the change to stop using a tasklet. Without reading the patch first: You need to disable the interrupt source while the tasklet/ threaded interrupt is handled. Otherwise the interrupt will keep coming and the tasklet/ threaded interrupt will have no chance to make progress. So the box will lock up. This is often overseen on fast machines because the interrupt needs a few usecs to trigger and so the CPU is able to make a little bit of progress between each trigger. > Thanks, > John Sebastian