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[2620:137:e000::1:20]) by mx.google.com with ESMTP id pi12-20020a17090b1e4c00b00256d7cc5b67si6664329pjb.133.2023.06.11.20.17.11; Sun, 11 Jun 2023 20:17:23 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=cuhGQNGp; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234270AbjFLDIZ (ORCPT + 99 others); Sun, 11 Jun 2023 23:08:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45648 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233094AbjFLDIR (ORCPT ); Sun, 11 Jun 2023 23:08:17 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 70AB4E5F; Sun, 11 Jun 2023 20:08:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=kYsaDINwgGyBkCQoDFNAkvO4v5df2UfOXAdRONE+VsA=; b=cuhGQNGphwJUwp0UMhVoYyu2tM H9F7lOZDO201p3qw3R1q8bQtHyuWu0Ww+eKkYHBp2SnCKuOjfD6kgi6m69yXk4p8uoAisA9qsHuMv NZ+EO4hMOMVyYXlSs63l3oG5dPiJ78trxjJexR5Sfy8VX8lTb2HSP6n5JCMPs1BrMk2t353Ht4z7y ajHHQh6qV3BcUH7Np9z/Hyh/VfcsEyJLb2dEfJQ7sbKUTpS2sgvFs+l5wj+LyR9ojtmX1GZtq1CuV 93PdN6DAikYuO8xL+WRqN403rR53yreatar8GTfojD5i+4Meicwk0sy7/jFlbJgYm2fwuoD1f6VgC oUxdexdQ==; Received: from [2601:1c2:980:9ec0::2764] (helo=bombadil.infradead.org) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1q8Xuf-002P78-1j; Mon, 12 Jun 2023 03:08:13 +0000 From: Randy Dunlap To: linux-kernel@vger.kernel.org Cc: Randy Dunlap , Suraj Jitindar Singh , Paolo Bonzini , Sean Christopherson , kvm@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org Subject: [PATCH 1/4] Documentation: KVM: make corrections to halt-polling.rst Date: Sun, 11 Jun 2023 20:08:07 -0700 Message-ID: <20230612030810.23376-2-rdunlap@infradead.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230612030810.23376-1-rdunlap@infradead.org> References: <20230612030810.23376-1-rdunlap@infradead.org> MIME-Version: 1.0 X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1768465202522444138?= X-GMAIL-MSGID: =?utf-8?q?1768465202522444138?= Module parameters are in sysfs, not debugfs, so change that. Remove superfluous "that" following "Note:". Hyphenate "system-wide" values. Hyphenate "trade-off". Don't treat "denial of service" as a verb. Signed-off-by: Randy Dunlap Cc: Suraj Jitindar Singh Cc: Paolo Bonzini Cc: Sean Christopherson Cc: kvm@vger.kernel.org Cc: Jonathan Corbet Cc: linux-doc@vger.kernel.org --- Documentation/virt/kvm/halt-polling.rst | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff -- a/Documentation/virt/kvm/halt-polling.rst b/Documentation/virt/kvm/halt-polling.rst --- a/Documentation/virt/kvm/halt-polling.rst +++ b/Documentation/virt/kvm/halt-polling.rst @@ -112,11 +112,11 @@ powerpc kvm-hv case. | | function. | | +-----------------------+---------------------------+-------------------------+ -These module parameters can be set from the debugfs files in: +These module parameters can be set from the sysfs files in: /sys/module/kvm/parameters/ -Note: that these module parameters are system wide values and are not able to +Note: these module parameters are system-wide values and are not able to be tuned on a per vm basis. Any changes to these parameters will be picked up by new and existing vCPUs the @@ -142,12 +142,12 @@ Further Notes global max polling interval (halt_poll_ns) then the host will always poll for the entire block time and thus cpu utilisation will go to 100%. -- Halt polling essentially presents a trade off between power usage and latency and +- Halt polling essentially presents a trade-off between power usage and latency and the module parameters should be used to tune the affinity for this. Idle cpu time is essentially converted to host kernel time with the aim of decreasing latency when entering the guest. - Halt polling will only be conducted by the host when no other tasks are runnable on that cpu, otherwise the polling will cease immediately and schedule will be invoked to - allow that other task to run. Thus this doesn't allow a guest to denial of service the - cpu. + allow that other task to run. Thus this doesn't allow a guest to cause denial of service + of the cpu.