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[23.128.96.18]) by mx.google.com with ESMTP id p15si17313530ilo.83.2021.05.16.18.58.26; Sun, 16 May 2021 18:58:40 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=kItJFM9j; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231358AbhEQA7o (ORCPT + 99 others); Sun, 16 May 2021 20:59:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229948AbhEQA7o (ORCPT ); Sun, 16 May 2021 20:59:44 -0400 Received: from mail-oi1-x22b.google.com (mail-oi1-x22b.google.com [IPv6:2607:f8b0:4864:20::22b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F0B7FC061573; Sun, 16 May 2021 17:58:28 -0700 (PDT) Received: by mail-oi1-x22b.google.com with SMTP id z3so5057118oib.5; Sun, 16 May 2021 17:58:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=N871goaSSdA/dHZRX1hFrtYRKni/828JahIgyz5A2aM=; b=kItJFM9jLVEaNef4/kLAjaaOLnFfG9EqgSOOGzXHTNg2UPXHOUUDBjK7XSrkEgJCK+ BVjOBK3a1a4z6KAiLiY8F1xGhYFVphhQmENvi1buPcgbusMMxgANLaO/Ral4XRKVhQcf ieo5m9VpVsllIn2u4Hwy/DLoHxqwISDDov3Rwiey4vghkI9+0/em6tA4D65rPhqRtyAV +NALy3/4wwdlRQzGXbiDAbRo/crn3LDsMJ/8UUSLbfgZMcvbv1QwhTyIrgDVubF0ZEsV fdSUXQZUao00m6rI72Oph26hBG1x9fdQDiuvIlrj3/2zCqyy+qgpeIrz/eedpjuSGY2y EhKw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=N871goaSSdA/dHZRX1hFrtYRKni/828JahIgyz5A2aM=; b=rbvwYVze/m7n69X8dyugjcbMKeft3kaQeTgIxb5+XzlQaTQWrAa6e1jIR8phPCqyaY 5M+6bRjN2QJ2RjizapfchFaPiNS2ejO7VIEu/hW6dhhvPOym4/BG1zisrgTvV743j9Wv DxaeninnL3jHufSf4rV8JFJoRicUe5u4lHhNwe0+tUBemR/dHKhc68fwEFGU73yPsckE +Sk+1Zuq1FTB/oyVmKbq57tnzBJc6mmdbYNyZ3NcWmKMh9eyCrOeaJNeKtJEw0Q3wkOW e0DEuvR/7iP1t/PHjk9jlU66xWVZNIIsMQ4w0FgNk3h7hxnc5VQlEYBspabSPwfaZ064 RctQ== X-Gm-Message-State: AOAM532+dYM1bFihKrc5qkXNtVuGhgSVAdyp5Vwf4SA4QGN9YiDxBaJ6 IgfEvAd0MqRGM1cPQyw5Um0dXaG4pCwCsagp1iq8l7RG X-Received: by 2002:a05:6808:206:: with SMTP id l6mr13191170oie.5.1621213108170; Sun, 16 May 2021 17:58:28 -0700 (PDT) MIME-Version: 1.0 References: <1620871084-4639-1-git-send-email-wanpengli@tencent.com> In-Reply-To: From: Wanpeng Li Date: Mon, 17 May 2021 08:58:17 +0800 Message-ID: Subject: Re: [PATCH v2 1/4] KVM: PPC: Book3S HV: exit halt polling on need_resched() as well To: David Matlack Cc: LKML , kvm list , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Ben Segall , Venkatesh Srinivas , Paul Mackerras , Suraj Jitindar Singh Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 15 May 2021 at 05:21, David Matlack wrote: > > On Wed, May 12, 2021 at 6:58 PM Wanpeng Li wrote: > > > > From: Wanpeng Li > > > > Inspired by commit 262de4102c7bb8 (kvm: exit halt polling on need_resched() > > as well), CFS_BANDWIDTH throttling will use resched_task() when there is just > > one task to get the task to block. It was likely allowing VMs to overrun their > > quota when halt polling. Due to PPC implements an arch specific halt polling > > logic, we should add the need_resched() checking there as well. > > > > Cc: Ben Segall > > Cc: Venkatesh Srinivas > > Cc: Jim Mattson > > Cc: David Matlack > > Cc: Paul Mackerras > > Cc: Suraj Jitindar Singh > > Signed-off-by: Wanpeng Li > > --- > > v1 -> v2: > > * update patch description > > > > arch/powerpc/kvm/book3s_hv.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c > > index 28a80d2..6199397 100644 > > --- a/arch/powerpc/kvm/book3s_hv.c > > +++ b/arch/powerpc/kvm/book3s_hv.c > > @@ -3936,7 +3936,8 @@ static void kvmppc_vcore_blocked(struct kvmppc_vcore *vc) > > break; > > } > > cur = ktime_get(); > > - } while (single_task_running() && ktime_before(cur, stop)); > > + } while (single_task_running() && !need_resched() && > > + ktime_before(cur, stop)); > > Consider moving this condition to a helper function that can be shared > between book3s and the generic halt-polling loop. Will do in the next version, thanks for review. :) Wanpeng