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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 40C7EC433F5 for ; Tue, 8 Feb 2022 03:24:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345225AbiBHDYB (ORCPT ); Mon, 7 Feb 2022 22:24:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53362 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231912AbiBHDYA (ORCPT ); Mon, 7 Feb 2022 22:24:00 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 6A950C043188 for ; Mon, 7 Feb 2022 19:24:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1644290639; 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=m8MFRztUxgRkrBpUpM+qrlg49h9/BEVue4eQaEH7ZJc=; b=K8nLvtlCFw8+cUFekM56iZKxA5ERQ82usD7Is/WoNrKGWmpphpixPAnCbSloKc1pMVi/S4 zxLkOuwUVZIo1++ErZGIPDa+OmusVTi/F+OWEkdbKaFeTrfO/CAB40OddR9KJpv3oxZZ7z R+sk9HIKn8IULSMtOP9DIWF39l7VH5s= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-616-TvQDvObAP4y1IoxvJ0qeVg-1; Mon, 07 Feb 2022 22:23:56 -0500 X-MC-Unique: TvQDvObAP4y1IoxvJ0qeVg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7F9711091DA3; Tue, 8 Feb 2022 03:23:55 +0000 (UTC) Received: from T590 (ovpn-8-31.pek2.redhat.com [10.72.8.31]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1A7AA46994; Tue, 8 Feb 2022 03:23:38 +0000 (UTC) Date: Tue, 8 Feb 2022 11:23:32 +0800 From: Ming Lei To: Jens Axboe Cc: linux-block@vger.kernel.org, Martin Wilck Subject: Re: [PATCH V2] lib/sbitmap: kill 'depth' from sbitmap_word Message-ID: References: <20220110072945.347535-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220110072945.347535-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Mon, Jan 10, 2022 at 03:29:45PM +0800, Ming Lei wrote: > Only the last sbitmap_word can have different depth, and all the others > must have same depth of 1U << sb->shift, so not necessary to store it in > sbitmap_word, and it can be retrieved easily and efficiently by adding > one internal helper of __map_depth(sb, index). > > Remove 'depth' field from sbitmap_word, then the annotation of > ____cacheline_aligned_in_smp for 'word' isn't needed any more. > > Not see performance effect when running high parallel IOPS test on > null_blk. > > This way saves us one cacheline(usually 64 words) per each sbitmap_word. > > Cc: Martin Wilck > Signed-off-by: Ming Lei Hello Guys, Ping... Thanks, Ming