From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794597166; b=CLJB2zB+Bz74elYJfK1aw9dGf84+X9mL44T9V+t25zV1DkWiQUx9y/ULxbjKzid8R1j3 1BYfOr9nQh59zz+nHjkRA9Ye6eYK1yb/ceLg0hBRsdUNG9reCPKwNz119iHTM6AVgBx6Q OowykVd913lmsr/5h5WliaZDwWCYB300uCmQMzi86/2W1cMN9Rpn9lSkWJpZuiO/8YPx+ kb4ItTIriWdVaOM20y6+IZ2zmHoopYElMmBsDkWlv40i/1NWAMnDq2IB3qajygLJ0k/JR 3Ezhd590iwGTIVBeTv+2uIPEaNK5y/i6mRlTKt6cLSJ0l9iLHbcVWjNAyciXicYNnSw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794597166; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=lpnM2hBW1D0k5wgh5lzVOzhc7no62X+neBhoHjY2U9Q=; b=qToQoFxrlk1JQqGoVYf7cRceYs27e30f7NM1359sn5Fu+FShyyi+x0R3TJ9pf1m+0upw 8z9KAOV44HuO7KJwhcWjhi/4GO5GTAM7kd/MhwAj98dPLelXUY+kt3g+T8ORpcGr2R0F4 UdH0DmZWPcOfq2xxJxpqAotnMDRDH+sA1omb//uL2KZvgBOAGt7pqF+zXEzpRsQo+hdvB LgiKWryDRGZtthybp87SFHyE2MvjqtnPeE9JB7aVGOadJKoKTEcRWegQOGW83HHP1FKVP usl1S1EIVvA1necOh8ngIHcpy6E8r0CP5DhDv9aQpbtPyfzxMfI76uZdd5penT0Dakg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XD8hznjB; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1B7B1606A33A for ; Fri, 13 Nov 2026 19:12:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XD8hznjB Received: by smtp.kernel.org (Postfix) with ESMTPSA id A650C1F000C4; Fri, 13 Nov 2026 19:12:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794597166; bh=lpnM2hBW1D0k5wgh5lzVOzhc7no62X+neBhoHjY2U9Q=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=XD8hznjBhvgfQFeGCf6JpoyANf0N6Dqyx2P5I4mviDTxKRON78vLaB9AHUkovE3iX uQtvRuDlDkYGTN6f7777FmxuU76cRFj7zshGAdj8vWeMgcYfQB+yaxxPp1Wv7LkFZG sjIdHSZ7Obic5r6Pnq/UD8fT4tiMPT35Ma4VdFi7lb+hZG/UEg8nb1j5hLbJVunJwe aU5lSMytEWYe+OQ3rSp6HRkleCLj5p0OnFkXZgnpnDfLAybYujtEFpG9S7URll8/YE vrJzzlOECGSj3ZBDVesbj1oVd0LTsYmO+BqlijyUvmEpZ57NAt4CVW/6ta476c822p aMEWBnkLo7jrQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 2/7] sched: restore preferred CPUs when hotplug removes the last one Reply-To: sashiko-reviews@lists.linux.dev To: "Yury Norov" Cc: linux-s390@vger.kernel.org, "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" In-Reply-To: <20261113184257.621707-3-ynorov@nvidia.com> References: <20261113184257.621707-1-ynorov@nvidia.com> <20261113184257.621707-3-ynorov@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 13 Nov 2026 19:12:45 +0000 X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > Offlining the last preferred CPU leaves cpu_preferred_mask empty. Normal > fair load balancing stops, potentially leaving CPUs idle while having > queued tasks. >=20 > Currently, steal governor is the only module that may modify the mask, > so it takes care of it by resetting the mask to mirror the active cpumask. >=20 > The design allows alternative preferred cpumask managers; relying on > loadable modules to maintain consistency of the core data structure > is not worthwhile in general. >=20 > Restore all remaining active CPUs as preferred in sched_cpu_deactivate() > path, without relying on the steal governor to recover. >=20 > Signed-off-by: Yury Norov Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261113184257.6217= 07-2-ynorov@nvidia.com?part=3D2