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[92.178.7.112]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3b47225a4e1sm3017984f8f.74.2025.07.04.10.51.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Jul 2025 10:51:42 -0700 (PDT) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 8bc68b03-58ff-11f0-b894-0df219b8e170 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=citrix.com; s=google; t=1751651503; x=1752256303; darn=lists.xenproject.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=W77tNreRPJQBVuNBI6j0n52aIgFeC0bceW25Zn1SucQ=; b=KlF/9rIAyailHiOfvYpF3ENEoXCuVsr2Pi4VmNobXwiI96IbvmKkEPJlICkK9bYj4d e13dTEIVfje2z/X1eOyumJ+lPaSBjH87FdfVHHuRMzhcdJlH8m3onVLCJYH0AvgK50pQ rDihChBHwJLgtjcpPqJ6Z8f/lam2CFrk+Mf9o= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1751651503; x=1752256303; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=W77tNreRPJQBVuNBI6j0n52aIgFeC0bceW25Zn1SucQ=; b=dQQmILwFclu4NZB8jjQmZDV0ZXLK1H4yvAts1Wtdde4TCgnpdSiDw9cKmBRKosZxMz m95Js/jBv+yFkYPtnHYO4Ka4G9OI4xaKjMDIJKWjQFD9fIwUVphW0wgiqCdR46M2crX2 CE+Jmcr9SnvdDZT0WxkgdXoqqMCz1Dtq9AM4+v+B/dBPCtqLbGU2wlQ3F+2yH0w2eFLC XtKoQuYipOPvxxOHPiRnhlFOyIYMT/f5OM4xSGCiuxR3vQc6veeeaT8739iceGlv7bs2 bzZw2SR3RvacTK1JWKTL1o1DzDhi+ImAEFYsaOj/2gOibx11HS8HF0N8Cpz8H2BH+mz1 sdmA== X-Gm-Message-State: AOJu0YzuVIvycwxGZdOYYHvDDyR8nI4Jn+vL+SbfbdU8jS7yrTPSjuIZ D7CAaSB7TmDgPOUqikZd+WdaMwoGj0tazvdZWMk9bMjZQ0YZvAF8HgVYX7HS+Q0OfWE= X-Gm-Gg: ASbGncvi2+acjcB33nHeM5i/sA+OWQ8s82ERB07wg7gybo3wu6gTNMi8YEtQyZ5JnqI siYskyzRET0RKwblnY+QZMy22UtPfATFoABHC4SVtMEI2zup9uGrWqa72EMWzz/ILF5Al64pjPw jZLhj7YDZZLf9hMxo3eFf+Vdure2zFaxGDN9VW9X78g9qo61s9e+e2Bu+vH6AgM6Bh0hDdLzbG1 7VbtLzgErsGACzNJun/GuSSrZWv5v6MDI0sfXwn/+4xP6nuiNHu69/m0EeGlmyv/PRIWrrVKuQ3 WDiHt8aFQyc3uWOeHlJvnBqezlgbcbxDB59wsAxyHSHUbnacrRG9jpIx9UcvHV1RsJJ1T3cQlPX Y+SO1RzyiQ37oBXmFpfHReyzK2EX8OA== X-Google-Smtp-Source: AGHT+IEJVFYF9P1Q0b5M1kyrSeKQ7g4cBHrY7/LMQDC0f4BWGljSFOjPG7mp+HSRafCr+M9x04uI4w== X-Received: by 2002:a05:6000:3ce:b0:3b2:ef53:5818 with SMTP id ffacd0b85a97d-3b4964eb1dfmr2853397f8f.5.1751651502845; Fri, 04 Jul 2025 10:51:42 -0700 (PDT) Date: Fri, 4 Jul 2025 19:51:41 +0200 From: Roger Pau =?utf-8?B?TW9ubsOp?= To: Andrew Cooper Cc: Xen-devel , Jan Beulich , Anthony PERARD , Michal Orzel , Julien Grall , Stefano Stabellini Subject: Re: [PATCH v2 2/6] x86/idle: Drop incorrect smp_mb() in mwait_idle_with_hints() Message-ID: References: <20250704163410.1412367-1-andrew.cooper3@citrix.com> <20250704163410.1412367-3-andrew.cooper3@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250704163410.1412367-3-andrew.cooper3@citrix.com> On Fri, Jul 04, 2025 at 05:34:06PM +0100, Andrew Cooper wrote: > With the recent simplifications, it becomes obvious that smp_mb() isn't the > right barrier. Strictly speaking, MONITOR is ordered as a load, but smp_rmb() > isn't correct either, as this only pertains to local ordering. All we need is > a compiler barrier(). > > Merge the barier() into the monitor() itself, along with an explantion. > > No functional change. > > Signed-off-by: Andrew Cooper Acked-by: Roger Pau Monné Thanks, Roger.