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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 AE4D9C433E0 for ; Thu, 21 Jan 2021 09:30:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 684EB239A1 for ; Thu, 21 Jan 2021 09:30:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728672AbhAUJaO (ORCPT ); Thu, 21 Jan 2021 04:30:14 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:30467 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728179AbhAUJCJ (ORCPT ); Thu, 21 Jan 2021 04:02:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611219643; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1+1P7b60HaR2MAzWv8XFsDjrssAyoeWJipGT+zaJVmE=; b=WIgCLIc98D/mVtehfsc0KhUW2TVB4bNP1B4YGP3unlLimQbP0t/WSjljHtBKQiFKH1LMuP UAw1kNgPgnTFHPmiSy7jgBN5WuxUsUAXSzr0ygkDxmcF9o+51YQ+6Pca7EYgkTOFgr46jW v77o+rjs2Tp41JMHREN1kyPV4eb6UWQ= 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-559-jDmMz9WnOKKAMlu3hfLq8w-1; Thu, 21 Jan 2021 04:00:39 -0500 X-MC-Unique: jDmMz9WnOKKAMlu3hfLq8w-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4DA241005D4E; Thu, 21 Jan 2021 09:00:38 +0000 (UTC) Received: from [10.72.13.67] (ovpn-13-67.pek2.redhat.com [10.72.13.67]) by smtp.corp.redhat.com (Postfix) with ESMTP id C7D0819C46; Thu, 21 Jan 2021 09:00:26 +0000 (UTC) Subject: Re: [PATCH 1/1] vhost scsi: allocate vhost_scsi with GFP_NOWAIT to avoid delay To: Dongli Zhang , virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, mst@redhat.com, pbonzini@redhat.com, stefanha@redhat.com, joe.jin@oracle.com, aruna.ramakrishna@oracle.com References: <20210121050328.7891-1-dongli.zhang@oracle.com> From: Jason Wang Message-ID: <3aa5c6ca-abd3-13c4-b6a6-504f3a52bae7@redhat.com> Date: Thu, 21 Jan 2021 17:00:25 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <20210121050328.7891-1-dongli.zhang@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/1/21 13:03, Dongli Zhang wrote: > The size of 'struct vhost_scsi' is order-10 (~2.3MB). It may take long time > delay by kzalloc() to compact memory pages when there is a lack of > high-order pages. As a result, there is latency to create a VM (with > vhost-scsi) or to hotadd vhost-scsi-based storage. > > The prior commit 595cb754983d ("vhost/scsi: use vmalloc for order-10 > allocation") prefers to fallback only when really needed, while this patch > changes allocation to GFP_NOWAIT in order to avoid the delay caused by > memory page compact. > > Cc: Aruna Ramakrishna > Cc: Joe Jin > Signed-off-by: Dongli Zhang > --- > Another option is to rework by reducing the size of 'struct vhost_scsi', > e.g., by replacing inline vhost_scsi.vqs with just memory pointers while > each vhost_scsi.vqs[i] should be allocated separately. Please let me > know if that option is better. > > drivers/vhost/scsi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c > index 4ce9f00ae10e..85eaa4e883f4 100644 > --- a/drivers/vhost/scsi.c > +++ b/drivers/vhost/scsi.c > @@ -1814,7 +1814,7 @@ static int vhost_scsi_open(struct inode *inode, struct file *f) > struct vhost_virtqueue **vqs; > int r = -ENOMEM, i; > > - vs = kzalloc(sizeof(*vs), GFP_KERNEL | __GFP_NOWARN | __GFP_RETRY_MAYFAIL); > + vs = kzalloc(sizeof(*vs), GFP_NOWAIT | __GFP_NOWARN); > if (!vs) { > vs = vzalloc(sizeof(*vs)); > if (!vs) Can we use kvzalloc? Thanks