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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 D50E1C43219 for ; Wed, 1 May 2019 16:51:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B007120644 for ; Wed, 1 May 2019 16:51:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726677AbfEAQv6 (ORCPT ); Wed, 1 May 2019 12:51:58 -0400 Received: from foss.arm.com ([217.140.101.70]:33974 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726434AbfEAQv6 (ORCPT ); Wed, 1 May 2019 12:51:58 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 48B2880D; Wed, 1 May 2019 09:51:57 -0700 (PDT) Received: from e107155-lin (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 35DD13F719; Wed, 1 May 2019 09:51:54 -0700 (PDT) Date: Wed, 1 May 2019 17:51:51 +0100 From: Sudeep Holla To: Oleg Nesterov Cc: x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Catalin Marinas , Will Deacon , Paul Mackerras , Michael Ellerman , Thomas Gleixner , Ingo Molnar , Richard Weinberger , jdike@addtoit.com, Steve Capper , Haibo Xu , Bin Lu , Andy Lutomirski , Borislav Petkov Subject: Re: [PATCH v2 3/6] x86: clean up _TIF_SYSCALL_EMU handling using ptrace_syscall_enter hook Message-ID: <20190501165151.GB12498@e107155-lin> References: <20190318104925.16600-1-sudeep.holla@arm.com> <20190318104925.16600-4-sudeep.holla@arm.com> <20190318153321.GA23521@redhat.com> <20190430164413.GA18913@e107155-lin> <20190501155711.GB30235@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190501155711.GB30235@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 01, 2019 at 05:57:11PM +0200, Oleg Nesterov wrote: > On 04/30, Sudeep Holla wrote: > > > > On Mon, Mar 18, 2019 at 04:33:22PM +0100, Oleg Nesterov wrote: > > > > > > And it seems that _TIF_WORK_SYSCALL_ENTRY needs some cleanups too... We don't need > > > "& _TIF_WORK_SYSCALL_ENTRY" in syscall_trace_enter, and _TIF_WORK_SYSCALL_ENTRY > > > should not include _TIF_NOHZ? > > > > > > > I was about to post the updated version and checked this to make sure I have > > covered everything or not. I had missed the above comment. All architectures > > have _TIF_NOHZ in their mask that they check to do work. And from x86, I read > > "...syscall_trace_enter(). Also includes TIF_NOHZ for enter_from_user_mode()" > > So I don't understand why _TIF_NOHZ needs to be dropped. > > I have already forgot this discussion... But after I glanced at this code again > I still think the same, and I don't understand why do you disagree. > Sorry, but I didn't have any disagreement, I just said I don't understand the usage on all architectures at that moment. > > Also if we need to drop, we can address that separately examining all archs. > > Sure, and I was only talking about x86. We can keep TIF_NOHZ and even > set_tsk_thread_flag(TIF_NOHZ) in context_tracking_cpu_set() if some arch needs > this but remove TIF_NOHZ from TIF_WORK_SYSCALL_ENTRY in arch/x86/include/asm/thread_info.h, > afaics this shouldn't make any difference. > OK, it's just x86, then I understand your point. I was looking at all the architectures, sorry for the confusion. > And I see no reason why x86 needs to use TIF_WORK_SYSCALL_ENTRY in > syscall_trace_enter(). > Agreed -- Regards, Sudeep 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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 C02DFC43219 for ; Wed, 1 May 2019 16:53:16 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 492B420835 for ; Wed, 1 May 2019 16:53:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 492B420835 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 44vPbZ0hd3zDqTm for ; Thu, 2 May 2019 02:53:14 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=arm.com (client-ip=217.140.101.70; helo=foss.arm.com; envelope-from=sudeep.holla@arm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by lists.ozlabs.org (Postfix) with ESMTP id 44vPZ73gKZzDq9V for ; Thu, 2 May 2019 02:51:58 +1000 (AEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 48B2880D; Wed, 1 May 2019 09:51:57 -0700 (PDT) Received: from e107155-lin (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 35DD13F719; Wed, 1 May 2019 09:51:54 -0700 (PDT) Date: Wed, 1 May 2019 17:51:51 +0100 From: Sudeep Holla To: Oleg Nesterov Subject: Re: [PATCH v2 3/6] x86: clean up _TIF_SYSCALL_EMU handling using ptrace_syscall_enter hook Message-ID: <20190501165151.GB12498@e107155-lin> References: <20190318104925.16600-1-sudeep.holla@arm.com> <20190318104925.16600-4-sudeep.holla@arm.com> <20190318153321.GA23521@redhat.com> <20190430164413.GA18913@e107155-lin> <20190501155711.GB30235@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190501155711.GB30235@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Haibo Xu , Steve Capper , Catalin Marinas , jdike@addtoit.com, x86@kernel.org, Will Deacon , linux-kernel@vger.kernel.org, Bin Lu , Richard Weinberger , Ingo Molnar , Paul Mackerras , Andy Lutomirski , Borislav Petkov , Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, May 01, 2019 at 05:57:11PM +0200, Oleg Nesterov wrote: > On 04/30, Sudeep Holla wrote: > > > > On Mon, Mar 18, 2019 at 04:33:22PM +0100, Oleg Nesterov wrote: > > > > > > And it seems that _TIF_WORK_SYSCALL_ENTRY needs some cleanups too... We don't need > > > "& _TIF_WORK_SYSCALL_ENTRY" in syscall_trace_enter, and _TIF_WORK_SYSCALL_ENTRY > > > should not include _TIF_NOHZ? > > > > > > > I was about to post the updated version and checked this to make sure I have > > covered everything or not. I had missed the above comment. All architectures > > have _TIF_NOHZ in their mask that they check to do work. And from x86, I read > > "...syscall_trace_enter(). Also includes TIF_NOHZ for enter_from_user_mode()" > > So I don't understand why _TIF_NOHZ needs to be dropped. > > I have already forgot this discussion... But after I glanced at this code again > I still think the same, and I don't understand why do you disagree. > Sorry, but I didn't have any disagreement, I just said I don't understand the usage on all architectures at that moment. > > Also if we need to drop, we can address that separately examining all archs. > > Sure, and I was only talking about x86. We can keep TIF_NOHZ and even > set_tsk_thread_flag(TIF_NOHZ) in context_tracking_cpu_set() if some arch needs > this but remove TIF_NOHZ from TIF_WORK_SYSCALL_ENTRY in arch/x86/include/asm/thread_info.h, > afaics this shouldn't make any difference. > OK, it's just x86, then I understand your point. I was looking at all the architectures, sorry for the confusion. > And I see no reason why x86 needs to use TIF_WORK_SYSCALL_ENTRY in > syscall_trace_enter(). > Agreed -- Regards, Sudeep 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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 A8A8DC43219 for ; Wed, 1 May 2019 16:52:08 +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 78B4420644 for ; Wed, 1 May 2019 16:52:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="pftBTKAJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 78B4420644 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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:In-Reply-To:MIME-Version:References: 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=CvPpbcM6Bwk+rcGoe1DskjCTA4OAZANYIRGaLyCq1pI=; b=pftBTKAJxJZVg3 C7wkqKeLKEW/z07kfBAL32xioH0mrLgnWvxXGVm+HTcfctcdKOmbOsb3ckuI8z51rpm/vdel8S5cn 7UJSzLGzcPW3WjXmdETwFw+RcYBrDn5lBe62/wnTogHn8cfKP13tuIqN427jcCnwRKsFwulJmQpoc abkma8TFcV2v6ENPWJm2gk3wrbx5A/RX6H5WlhuQ5ODQpNvncx97LhhONl4qdRu2WCR4OB+wVCbEB DcwmgCHUmF/oUOhIWrHVZbQF8Mh55OjNHrMS4PSMutjr1fbWjBddjtBTi8K2g3hgFXI5SsA0Tc6Gb /hX29KOs9AP67E8u7+iA==; 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 1hLsSg-0005yx-3w; Wed, 01 May 2019 16:52:02 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hLsSd-0005xz-IW for linux-arm-kernel@lists.infradead.org; Wed, 01 May 2019 16:52:00 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 48B2880D; Wed, 1 May 2019 09:51:57 -0700 (PDT) Received: from e107155-lin (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 35DD13F719; Wed, 1 May 2019 09:51:54 -0700 (PDT) Date: Wed, 1 May 2019 17:51:51 +0100 From: Sudeep Holla To: Oleg Nesterov Subject: Re: [PATCH v2 3/6] x86: clean up _TIF_SYSCALL_EMU handling using ptrace_syscall_enter hook Message-ID: <20190501165151.GB12498@e107155-lin> References: <20190318104925.16600-1-sudeep.holla@arm.com> <20190318104925.16600-4-sudeep.holla@arm.com> <20190318153321.GA23521@redhat.com> <20190430164413.GA18913@e107155-lin> <20190501155711.GB30235@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190501155711.GB30235@redhat.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190501_095159_617020_06AD0854 X-CRM114-Status: GOOD ( 22.08 ) 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: Haibo Xu , Steve Capper , Catalin Marinas , jdike@addtoit.com, x86@kernel.org, Will Deacon , linux-kernel@vger.kernel.org, Bin Lu , Richard Weinberger , Ingo Molnar , Paul Mackerras , Andy Lutomirski , Michael Ellerman , Borislav Petkov , Thomas Gleixner , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org 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 Wed, May 01, 2019 at 05:57:11PM +0200, Oleg Nesterov wrote: > On 04/30, Sudeep Holla wrote: > > > > On Mon, Mar 18, 2019 at 04:33:22PM +0100, Oleg Nesterov wrote: > > > > > > And it seems that _TIF_WORK_SYSCALL_ENTRY needs some cleanups too... We don't need > > > "& _TIF_WORK_SYSCALL_ENTRY" in syscall_trace_enter, and _TIF_WORK_SYSCALL_ENTRY > > > should not include _TIF_NOHZ? > > > > > > > I was about to post the updated version and checked this to make sure I have > > covered everything or not. I had missed the above comment. All architectures > > have _TIF_NOHZ in their mask that they check to do work. And from x86, I read > > "...syscall_trace_enter(). Also includes TIF_NOHZ for enter_from_user_mode()" > > So I don't understand why _TIF_NOHZ needs to be dropped. > > I have already forgot this discussion... But after I glanced at this code again > I still think the same, and I don't understand why do you disagree. > Sorry, but I didn't have any disagreement, I just said I don't understand the usage on all architectures at that moment. > > Also if we need to drop, we can address that separately examining all archs. > > Sure, and I was only talking about x86. We can keep TIF_NOHZ and even > set_tsk_thread_flag(TIF_NOHZ) in context_tracking_cpu_set() if some arch needs > this but remove TIF_NOHZ from TIF_WORK_SYSCALL_ENTRY in arch/x86/include/asm/thread_info.h, > afaics this shouldn't make any difference. > OK, it's just x86, then I understand your point. I was looking at all the architectures, sorry for the confusion. > And I see no reason why x86 needs to use TIF_WORK_SYSCALL_ENTRY in > syscall_trace_enter(). > Agreed -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel