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=-5.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED 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 2DC73C04EBF for ; Tue, 4 Dec 2018 17:26:47 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 EA77D2081C for ; Tue, 4 Dec 2018 17:26:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="toelAKQ6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EA77D2081C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=gWqX6p3qfzRJvtYiZRYvauxIHGFtEOW3nwP+mj89WSw=; b=toelAKQ6SDffTF ulPwiYIcuR0E8Bhq8ElxmbF37YbPMpPL7msDEWtcXVInjDcxS6pak55N38Wmhjg5+DRgJ9YzzY4ay 36uWsOIrAiBjsb1R1rofZoIROKTVXVYxX50G97nVSC8rh8aypPqoKibMctGgXATLUzQHLxh4kFQSA H5xYNCwBGyOFwL8JzKGqKBwoUR7GfdXkBHUbzBB60c8AacGAkoqEd3Fk8StqpKnmiK349nhqH5hOH PKIkI2j6Tfg1MccKvhDIxPTjVrXQwY7jNDhXRgxDjN7G0S/AzILSDJ83OoCoAZDR0W4ontOkqIIjN f5AGMJhdwKJ+zojBuetQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gUET5-0003BY-VX; Tue, 04 Dec 2018 17:26:43 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gUET2-00039Q-KE for linux-arm-kernel@lists.infradead.org; Tue, 04 Dec 2018 17:26:42 +0000 Received: from vmware.local.home (unknown [208.91.3.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ABD9A2081C; Tue, 4 Dec 2018 17:26:29 +0000 (UTC) Date: Tue, 4 Dec 2018 12:26:27 -0500 From: Steven Rostedt To: Will Deacon Subject: Re: [PATCH 3/3] arm64: ftrace: add cond_resched() to func ftrace_make_(call|nop) Message-ID: <20181204122627.225befaa@vmware.local.home> In-Reply-To: <20181204111242.GA32596@arm.com> References: <20181130150956.27620-1-anders.roxell@linaro.org> <20181203192228.GC29028@arm.com> <20181204005012.11f73df9@vmware.local.home> <20181204111242.GA32596@arm.com> X-Mailer: Claws Mail 3.15.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181204_092640_680780_6F711BD5 X-CRM114-Status: GOOD ( 16.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Anders Roxell , Kees Cook , Arnd Bergmann , Catalin Marinas , Linux Kernel Mailing List , Ingo Molnar , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, 4 Dec 2018 11:12:43 +0000 Will Deacon wrote: > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > > index 8ef9fc226037..42e89397778b 100644 > > --- a/kernel/trace/ftrace.c > > +++ b/kernel/trace/ftrace.c > > @@ -2393,11 +2393,14 @@ void __weak ftrace_replace_code(int enable) > > { > > struct dyn_ftrace *rec; > > struct ftrace_page *pg; > > + bool schedulable; > > int failed; > > > > if (unlikely(ftrace_disabled)) > > return; > > > > + schedulable = !irqs_disabled() & !preempt_count(); > > Looks suspiciously like a bitwise preemptible() to me! Ah, thanks. Yeah, that should have been &&. But what did you expect. I didn't even compile this ;-) > > > + > > do_for_each_ftrace_rec(pg, rec) { > > > > if (rec->flags & FTRACE_FL_DISABLED) > > @@ -2409,6 +2412,8 @@ void __weak ftrace_replace_code(int enable) > > /* Stop processing */ > > return; > > } > > + if (schedulable) > > + cond_resched(); > > } while_for_each_ftrace_rec(); > > } > > If this solves the problem in core code, them I'm all for it. Otherwise, I > was thinking of rolling our own ftrace_replace_code() for arm64, but that's > going to involve a fair amount of duplication. > If it does, then I'll add it. Or take a patch for it ;-) My main concern is that this can be called from non schedulable context. -- Steve _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel