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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 40CF3CD5BDF for ; Thu, 5 Sep 2024 17:02:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1smFrP-0005dF-K7; Thu, 05 Sep 2024 13:01:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1smFqt-0004L0-Li for qemu-devel@nongnu.org; Thu, 05 Sep 2024 13:01:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1smFqq-0005st-3y for qemu-devel@nongnu.org; Thu, 05 Sep 2024 13:00:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1725555655; h=from:from:reply-to: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=VFmBpS4JQQMG2V3riAbJelszRCuxGmh05fjZXIXylJ4=; b=JrDC7JQ/7wnkjSara+Ja5/8eC/I8ZMmEnvgAY6mviUCSE0RWUhdBxhbIdaY2UQV21GfcZk ZRq2N6uSsixe1zCfUcT6+P+hnN8NH5hxnX3CG9Wvx3SwwC+cNqa5l1YCLlnvltkW5bIk0L +i0xbFzcCjk2UMJqCBKJruXKHB7WH/o= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-556-HBjGQzKJMOWel57sIl1TOw-1; Thu, 05 Sep 2024 13:00:53 -0400 X-MC-Unique: HBjGQzKJMOWel57sIl1TOw-1 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B4805193E8D9; Thu, 5 Sep 2024 17:00:51 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.53]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9F80419560AF; Thu, 5 Sep 2024 17:00:50 +0000 (UTC) Date: Thu, 5 Sep 2024 18:00:46 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Tiago Pasqualini Cc: qemu-devel@nongnu.org Subject: Re: [PATCH v2] crypto: run qcrypto_pbkdf2_count_iters in a new thread Message-ID: References: <20240904235230.199672-1-tiago.pasqualini@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240904235230.199672-1-tiago.pasqualini@canonical.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 11 X-Spam_score: 1.1 X-Spam_bar: + X-Spam_report: (1.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.142, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Sep 04, 2024 at 08:52:30PM -0300, Tiago Pasqualini wrote: > CPU time accounting in the kernel has been demonstrated to have a > sawtooth pattern[1][2]. This can cause the getrusage system call to > not be as accurate as we are expecting, which can cause this calculation > to stall. > > The kernel discussions shows that this inaccuracy happens when CPU time > gets big enough, so this patch changes qcrypto_pbkdf2_count_iters to run > in a fresh thread to avoid this inaccuracy. It also adds a sanity check > to fail the process if CPU time is not accounted. > > [1] https://lore.kernel.org/lkml/159231011694.16989.16351419333851309713.tip-bot2@tip-bot2/ > [2] https://lore.kernel.org/lkml/20221226031010.4079885-1-maxing.lan@bytedance.com/t/#m1c7f2fdc0ea742776a70fd1aa2a2e414c437f534 > > Resolves: #2398 > Signed-off-by: Tiago Pasqualini > --- > crypto/pbkdf.c | 53 +++++++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 46 insertions(+), 7 deletions(-) Reviewed-by: Daniel P. Berrangé and queued. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|