From patchwork Tue Nov 24 07:01:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 11927295 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 60473C2D0E4 for ; Tue, 24 Nov 2020 07:01:35 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 CBA532080A for ; Tue, 24 Nov 2020 07:01:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="DuiB6acu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CBA532080A Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.35378.66897 (Exim 4.92) (envelope-from ) id 1khSKE-0001nR-CI; Tue, 24 Nov 2020 07:01:18 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 35378.66897; Tue, 24 Nov 2020 07:01:18 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1khSKE-0001nH-7p; Tue, 24 Nov 2020 07:01:18 +0000 Received: by outflank-mailman (input) for mailman id 35378; Tue, 24 Nov 2020 07:01:17 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1khSKD-0001kq-3z for xen-devel@lists.xenproject.org; Tue, 24 Nov 2020 07:01:17 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 38370360-fb20-49fc-88ce-cf4fc5afc72c; Tue, 24 Nov 2020 07:01:10 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A013DADCD; Tue, 24 Nov 2020 07:01:09 +0000 (UTC) Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1khSKD-0001kq-3z for xen-devel@lists.xenproject.org; Tue, 24 Nov 2020 07:01:17 +0000 X-Inumbo-ID: 38370360-fb20-49fc-88ce-cf4fc5afc72c Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 38370360-fb20-49fc-88ce-cf4fc5afc72c; Tue, 24 Nov 2020 07:01:10 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1606201269; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uY+rObtaesBiYwhFR54/hfk+UTURWjLhSDOKmBjo9Hk=; b=DuiB6acuqrH4C2absqcxEFRbDrXB2fDjBgSxIwxTz1tlybaHV+QEpsJU02wI1BLe46mAw0 QMHW2k4JCUWGGaNTw0+FqZKNpJPpydJ3mutCADpZN9FTGdUIzLDMcOLuaegMoB+IhE4m7h YMuNtsNn46pIrv/Xlh+AWDys/+6aZfQ= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id A013DADCD; Tue, 24 Nov 2020 07:01:09 +0000 (UTC) From: Juergen Gross To: xen-devel@lists.xenproject.org Cc: Juergen Gross , Andrew Cooper , George Dunlap , Ian Jackson , Jan Beulich , Julien Grall , Stefano Stabellini , Wei Liu Subject: [PATCH v7 2/3] xen/events: modify struct evtchn layout Date: Tue, 24 Nov 2020 08:01:05 +0100 Message-Id: <20201124070106.26854-3-jgross@suse.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201124070106.26854-1-jgross@suse.com> References: <20201124070106.26854-1-jgross@suse.com> MIME-Version: 1.0 In order to avoid latent races when updating an event channel put xen_consumer and pending fields in different bytes. At the same time move some other fields around to have less implicit paddings and to keep related fields more closely together. Signed-off-by: Juergen Gross --- xen/include/xen/sched.h | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h index a345cc01f8..e6d09aa055 100644 --- a/xen/include/xen/sched.h +++ b/xen/include/xen/sched.h @@ -80,8 +80,7 @@ extern domid_t hardware_domid; #define EVTCHNS_PER_GROUP (BUCKETS_PER_GROUP * EVTCHNS_PER_BUCKET) #define NR_EVTCHN_GROUPS DIV_ROUND_UP(MAX_NR_EVTCHNS, EVTCHNS_PER_GROUP) -#define XEN_CONSUMER_BITS 3 -#define NR_XEN_CONSUMERS ((1 << XEN_CONSUMER_BITS) - 1) +#define NR_XEN_CONSUMERS 8 struct evtchn { @@ -94,9 +93,10 @@ struct evtchn #define ECS_VIRQ 5 /* Channel is bound to a virtual IRQ line. */ #define ECS_IPI 6 /* Channel is bound to a virtual IPI line. */ u8 state; /* ECS_* */ - u8 xen_consumer:XEN_CONSUMER_BITS; /* Consumer in Xen if nonzero */ - u8 pending:1; - u16 notify_vcpu_id; /* VCPU for local delivery notification */ +#ifndef NDEBUG + u8 old_state; /* State when taking lock in write mode. */ +#endif + u8 xen_consumer; /* Consumer in Xen if nonzero */ u32 port; union { struct { @@ -113,11 +113,13 @@ struct evtchn } pirq; /* state == ECS_PIRQ */ u16 virq; /* state == ECS_VIRQ */ } u; - u8 priority; -#ifndef NDEBUG - u8 old_state; /* State when taking lock in write mode. */ -#endif - u32 fifo_lastq; /* Data for fifo events identifying last queue. */ + + /* FIFO event channels only. */ + u8 pending; + u8 priority; + u16 notify_vcpu_id; /* VCPU for local delivery notification */ + u32 fifo_lastq; /* Data for identifying last queue. */ + #ifdef CONFIG_XSM union { #ifdef XSM_NEED_GENERIC_EVTCHN_SSID