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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 14D5EC433E7 for ; Wed, 2 Sep 2020 12:27:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E130E2083B for ; Wed, 2 Sep 2020 12:27:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="S0Z48kmz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726479AbgIBM1E (ORCPT ); Wed, 2 Sep 2020 08:27:04 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:32677 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726177AbgIBM07 (ORCPT ); Wed, 2 Sep 2020 08:26:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599049618; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=9eHg4n9Mrbjk8IN5UH1B1k5VMpWNZ5atFdJ2hB4iC3M=; b=S0Z48kmzqTZR3mZ2SzcBsu4yPxJpC99YercEJ17vRilYfNUN8kpIy/v1jxxZgfvY9EbTX4 GmFEt5eCRhNJOoSOTJiC9BxEmTV34ssFupnRdtdRrjZPcEcWDXclNIQmF5strkxhTOFQMA o1yBzp5gJ1q93FHS14lbZQ4Xs++DXXQ= 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-113-puG_S4o8M2q_OG0lkFs1QQ-1; Wed, 02 Sep 2020 08:26:57 -0400 X-MC-Unique: puG_S4o8M2q_OG0lkFs1QQ-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 37AE41888A3E; Wed, 2 Sep 2020 12:26:55 +0000 (UTC) Received: from localhost (ovpn-12-189.pek2.redhat.com [10.72.12.189]) by smtp.corp.redhat.com (Postfix) with ESMTP id 65D7665F5E; Wed, 2 Sep 2020 12:26:51 +0000 (UTC) From: Ming Lei To: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Cc: Ming Lei , Sagi Grimberg , Tejun Heo , Christoph Hellwig , Jens Axboe , Bart Van Assche Subject: [PATCH V2 0/2] percpu_ref & block: reduce memory footprint of percpu_ref in fast path Date: Wed, 2 Sep 2020 20:26:41 +0800 Message-Id: <20200902122643.634143-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, The 1st patch removes memory footprint of percpu_ref in fast path from 7 words to 2 words, since it is often used in fast path and embedded in user struct. The 2nd patch moves .q_usage_counter to 1st cacheline of 'request_queue'. Simple test on null_blk shows ~2% IOPS boost on one 16cores(two threads per core) machine, dual socket/numa. V2: - pass 'gfp' to kzalloc() for fixing block/027 failure reported by kernel test robot - protect percpu_ref_is_zero() with destroying percpu-refcount by spin lock Ming Lei (2): percpu_ref: reduce memory footprint of percpu_ref in fast path block: move 'q_usage_counter' into front of 'request_queue' drivers/infiniband/sw/rdmavt/mr.c | 2 +- include/linux/blkdev.h | 3 +- include/linux/percpu-refcount.h | 45 ++++------- lib/percpu-refcount.c | 128 ++++++++++++++++++++++-------- 4 files changed, 115 insertions(+), 63 deletions(-) Cc: Sagi Grimberg Cc: Tejun Heo Cc: Christoph Hellwig Cc: Jens Axboe Cc: Bart Van Assche -- 2.25.2