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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 16677C35669 for ; Fri, 21 Feb 2020 20:50:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6114206EF for ; Fri, 21 Feb 2020 20:50:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XDxJ2bEV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726725AbgBUUuK (ORCPT ); Fri, 21 Feb 2020 15:50:10 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:39565 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726526AbgBUUuJ (ORCPT ); Fri, 21 Feb 2020 15:50:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582318208; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PW4bV9owzCR0GrgSI7FyXhQJGcIlBlHHH9mjBSVotEs=; b=XDxJ2bEVsHBgbQDeV8zKM+lgYXnVkfCc9ge1rC9hgR00LvakH0AylkZz9m7iQHuhTWBZJp 11Otus4E+FAh/O0aK/bpA9bRRt/aD3Pe9nbGI95ACVE+Y7x2P3uOEClIs0V58NA0zEIhfL TcK5sGDoB6u3tTcAVwdbs5oJx8SAdCs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-9-XwUH1Eu0PoGYWJzsQ7-TUA-1; Fri, 21 Feb 2020 15:50:07 -0500 X-MC-Unique: XwUH1Eu0PoGYWJzsQ7-TUA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 71CC2800D4E; Fri, 21 Feb 2020 20:50:05 +0000 (UTC) Received: from krava (ovpn-204-57.brq.redhat.com [10.40.204.57]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 90CC65C1D4; Fri, 21 Feb 2020 20:50:00 +0000 (UTC) Date: Fri, 21 Feb 2020 21:49:57 +0100 From: Jiri Olsa To: Sebastian Andrzej Siewior Cc: Steven Rostedt , Jiri Olsa , linux-rt-users@vger.kernel.org, Thomas Gleixner , Juri Lelli , Arnaldo Carvalho de Melo Subject: Re: [PATCH RT] tracing: make preempt_lazy and migrate_disable counter smaller Message-ID: <20200221204957.GE657629@krava> References: <20200221153541.681468-1-jolsa@kernel.org> <20200221104922.5ea8bb5f@gandalf.local.home> <20200221161030.GC657629@krava> <20200221112152.031b4230@gandalf.local.home> <20200221163735.53wt2fqoajcuj2js@linutronix.de> <20200221174419.7r5zxfkvz4yrndi2@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200221174419.7r5zxfkvz4yrndi2@linutronix.de> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Sender: linux-rt-users-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On Fri, Feb 21, 2020 at 06:44:19PM +0100, Sebastian Andrzej Siewior wrote: > The migrate_disable counter should not exceed 255 so it is enough to > store it in an 8bit field. > With this change we can move the `preempt_lazy_count' member into the > gap so the whole struct shrinks by 4 bytes to 12 bytes in total. > > Signed-off-by: Sebastian Andrzej Siewior > --- > include/linux/trace_events.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h > index f3b1ef07e4a5f..c8b3f06cb5ed7 100644 > --- a/include/linux/trace_events.h > +++ b/include/linux/trace_events.h > @@ -62,9 +62,9 @@ struct trace_entry { > unsigned char flags; > unsigned char preempt_count; > int pid; > - unsigned short migrate_disable; > - unsigned short padding; > + unsigned char migrate_disable; > unsigned char preempt_lazy_count; > + unsigned short padding; also we still need to put preempt_lazy_count as common field: __common_field(unsigned char, preempt_lazy_count); jirka