From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753838AbbKBRbz (ORCPT ); Mon, 2 Nov 2015 12:31:55 -0500 Received: from mail-pa0-f53.google.com ([209.85.220.53]:33821 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752190AbbKBRbx (ORCPT ); Mon, 2 Nov 2015 12:31:53 -0500 Message-ID: <56379E06.3040008@linaro.org> Date: Mon, 02 Nov 2015 09:31:50 -0800 From: "Shi, Yang" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Steven Rostedt CC: Daniel Borkmann , Alexei Starovoitov , ast@kernel.org, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, netdev@vger.kernel.org, linaro-kernel@lists.linaro.org Subject: Re: [PATCH] bpf: convert hashtab lock to raw lock References: <1446243386-26582-1-git-send-email-yang.shi@linaro.org> <20151031000356.GA28070@Alexeis-MacBook-Pro.local> <20151031094736.494427d7@grimm.local.home> <56350A86.5090500@iogearbox.net> <5637997D.1020502@linaro.org> <20151102122405.56dd97a1@gandalf.local.home> In-Reply-To: <20151102122405.56dd97a1@gandalf.local.home> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/2/2015 9:24 AM, Steven Rostedt wrote: > On Mon, 02 Nov 2015 09:12:29 -0800 > "Shi, Yang" wrote: > >> Yes, it is common practice for converting sleepable spin lock to raw >> spin lock in -rt to avoid scheduling in atomic context bug. > > Note, in a lot of cases we don't just convert spin_locks to raw because > of atomic context. There's times we need to change the design where the > lock is not taken in atomic context (switching preempt_disable() to a > local_lock() for example). Yes, definitely. Understood. Thanks, Yang > > But bpf is much like ftrace and kprobes where they can be taken almost > anywhere, and the do indeed need to be raw. > > -- Steve >