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 EED6AC433F5 for ; Tue, 31 May 2022 15:31:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345743AbiEaPbo (ORCPT ); Tue, 31 May 2022 11:31:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48292 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239001AbiEaPbn (ORCPT ); Tue, 31 May 2022 11:31:43 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54793271 for ; Tue, 31 May 2022 08:31:41 -0700 (PDT) Date: Tue, 31 May 2022 17:31:38 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1654011100; 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=7FREbcwOrqto74ZUT8TXex2Yk5yLeYzeDM3FJWSDdjA=; b=kvDOJ6dDu14wIG8t01rGaRnyEpB3cnqTw4XbDadtE6U3NpZJ1JtldJlC8X1+kbxMdGkGPF RPJT9vB51fw3p+0pGI20x9md4qgo1YI9c/6jrSURQF8mJ8rOeyKPK4TcoSTLPHC299Qq1U CkL5CjiTEBdV1q6OLGDZD6MaP+kLv+Qx1uBSVEqTw/Cm6rJyuL+JJVmLHahdYCh/H2xIxz eWur2Qm1RxQ/MClqGeoTW/cAytDs4kn8jxOas/hGmBYOj4vDzadxghQM5ap7omTNYyhaK5 qec2blypoEIRcQJ/tBXVrs0bKknucJBrb+aNEiErwQoGqFqPPLAV77dgUoyfiw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1654011100; 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=7FREbcwOrqto74ZUT8TXex2Yk5yLeYzeDM3FJWSDdjA=; b=RBrBx0m6Pk3Pb0KU7UdWvhnfmRLjkwha7sBwlF64y4TLtbH+lviDRMX1A5+u1UOpAQHKV0 PDQgwwLMQi7j7HCQ== 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> <0ebd951e-f047-1930-4ace-f5199921bf9a@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <0ebd951e-f047-1930-4ace-f5199921bf9a@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On 2022-05-31 16:26:26 [+0100], John Garry wrote: > On 31/05/2022 16:17, Sebastian Andrzej Siewior wrote: > > > 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. > > > > ah, so we would need IRQF_ONESHOT flag set to keep the interrupt line > disabled until the threaded part completes, right? This is one way of doing it and this is what threaded irqs do. However this requires all handler to specify that option which is not very compatible with shared handler. > Thanks, > John Sebastian