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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 7C24FC433E0 for ; Fri, 15 Jan 2021 03:54:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27EBD23A40 for ; Fri, 15 Jan 2021 03:54:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732747AbhAODyS (ORCPT ); Thu, 14 Jan 2021 22:54:18 -0500 Received: from mx2.suse.de ([195.135.220.15]:50054 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726431AbhAODyR (ORCPT ); Thu, 14 Jan 2021 22:54:17 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 89A08AB7F; Fri, 15 Jan 2021 03:53:35 +0000 (UTC) Date: Thu, 14 Jan 2021 19:53:27 -0800 From: Davidlohr Bueso To: Jassi Brar Cc: rob.rice@broadcom.com, Linux Kernel Mailing List , Davidlohr Bueso Subject: Re: [PATCH] mailbox: bcm: Replace tasklet with threaded irq Message-ID: <20210115035327.xckiigalv3qps7ke@offworld> References: <20210115002134.117637-1-dave@stgolabs.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20201120 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 14 Jan 2021, Jassi Brar wrote: >On Thu, Jan 14, 2021 at 6:21 PM Davidlohr Bueso wrote: >> >> Tasklets have long been deprecated as being too heavy on the system >> by running in irq context - and this is not a performance critical >> path. If a higher priority process wants to run, it must wait for >> the tasklet to finish before doing so. >> >> Use a more suitable alternative such as threaded irqs and do the >> async work in process context. >> >> Signed-off-by: Davidlohr Bueso >> --- >Please cc the author and other contributors to this file, esp when >this is vendor specific code. So looking at who to Cc I noticed: commit 8aef00f090bcbe5237c5a6628e7c000890267efe Author: Rob Rice Date: Mon Nov 14 13:26:01 2016 -0500 mailbox: bcm-pdc: Convert from threaded IRQ to tasklet Previously used threaded IRQs in the PDC driver to defer processing the rx DMA ring after getting an rx done interrupt. Instead, use a tasklet at normal priority for deferred processing. ... which is exactly the opposite of what modern Linux should be doing. Rob, could this not be done in process context? Thanks, Davidlohr