From patchwork Mon Aug 12 20:03:01 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 2843293 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 7CC679F294 for ; Mon, 12 Aug 2013 20:03:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 351122051A for ; Mon, 12 Aug 2013 20:03:37 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3006720515 for ; Mon, 12 Aug 2013 20:03:36 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1V8yKz-0007Ll-Nt; Mon, 12 Aug 2013 20:03:34 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1V8yKx-0004kP-GH; Mon, 12 Aug 2013 20:03:31 +0000 Received: from chamillionaire.breakpoint.cc ([2001:4d88:1ffa:82:880:aa0:9009:64ae]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1V8yKu-0004jp-OP for linux-arm-kernel@lists.infradead.org; Mon, 12 Aug 2013 20:03:29 +0000 Received: from bigeasy by Chamillionaire.breakpoint.cc with local (Exim 4.80) (envelope-from ) id 1V8yKU-0004cV-J1; Mon, 12 Aug 2013 22:03:02 +0200 Date: Mon, 12 Aug 2013 22:03:01 +0200 From: Sebastian Andrzej Siewior To: Russell King - ARM Linux Subject: [PATCH 2/2 v2] arm: Allow forced irq threading Message-ID: <20130812200301.GB4181@breakpoint.cc> References: <20130214205204.109023136@linutronix.de> <20130214205304.993009840@linutronix.de> <20130214214931.GK17833@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130812_160328_955270_3D0494BD X-CRM114-Status: GOOD ( 16.96 ) X-Spam-Score: -4.7 (----) Cc: Thomas Gleixner , Will Deacon , LAK X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-7.0 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Thomas Gleixner All timer interrupts and the perf interrupt are marked NO_THREAD, so its safe to allow forced interrupt threading. Signed-off-by: Thomas Gleixner Signed-off-by: Sebastian Andrzej Siewior --- On Thu, Feb 14, 2013 at 11:04:48PM +0100, Thomas Gleixner wrote: > On Thu, 14 Feb 2013, Russell King - ARM Linux wrote: > > > What effect does this have on IRQ latency, particularly on the slower CPUs? > > It does not affect anything unless you add "threadirqs" to the kernel > command line. This command line argument puts the kernel into forced > irq threading mode. Otherwise it just works as now. I reposted the patch since it no longer applies clean on v3.11-rc5. From what tglx explained, I don't think there are any outstanding issues, are there? arch/arm/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 43594d5..405e4c0 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -20,6 +20,7 @@ config ARM select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER select HARDIRQS_SW_RESEND + select IRQ_FORCED_THREADING select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL select HAVE_ARCH_KGDB select HAVE_ARCH_SECCOMP_FILTER