From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7604D395240; Wed, 5 Aug 2026 10:49:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785926960; cv=none; b=d1HCueXf8N0Mhzbk9lsDZgRRh54oBPJj88ZIiMGpau07qccz+kEokjoYW9KXIHaxD5xJgX9I8kPMEB8zvnSJAdO8sU28faQ25sKdH3vOHRgVys55PNpnDf1m1mEseVQqeHH6vUHsSzycuRcww6d7OwCgnH26JgnVOjjl345MPnM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785926960; c=relaxed/simple; bh=aoD/8/1rOkU6dw5q8BatbQAD+dzeArBlFEInxDyYqfo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cj9CVhw3/PXhcsoby9jKGUmSoXE9RbWtdC2AQWvLtf1ulBhfnMbL/y+JrxNlVzg+dhbM8bifCJ1wWhtCGNGXB7yuPukPuYUDeobb5zCOgGmDyg6T0LpRj4iuYHCW50fNnHAjsD/VLiQXY1akJABnjvMTz70pZO4tazcJ0yh3w94= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=vNa/D+Cd; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="vNa/D+Cd" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=UbrOXul+0gfZDUnSzuW045Fm9Rg7ZjjUqlD/EelI48c=; b=vNa/D+CdvoaCuTqElHssEIbqzj xbW+Xz+ulkj3ZVqRL0uizaEMF2cOfJVoMI87EH3uSy5lY6kc+li4irraEUEAqjQKAs1I2HyVSOK5B ognfe93l/ptoc2a4Qr5Q8yfrISYy+A7y0wN9VTapeHcbl+d7Knx45crj5quYkWT8d24EKP2Bl9y1e CLKzZiqk443Ir9GhchYsKKlUkVoTVkS7amVu2hPFD/YiumHF9X8hMZw9F9gvShYnNemvp2Jk+BR28 V435Jc32E7TKyOeC9oiXHV1Wpxb5kkiZNzbaFCEDfHqN2PgtBhDVcUNIBirgs8EzKIGOG2I9GMxDX i8g/Fgjw==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrY92-00000001dOV-0Bw3; Wed, 05 Aug 2026 09:42:40 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 8D38F300E7E; Wed, 05 Aug 2026 11:42:19 +0200 (CEST) Date: Wed, 5 Aug 2026 11:42:19 +0200 From: Peter Zijlstra To: Shrikanth Hegde Cc: Boqun Feng , Madhavan Srinivasan , "Christophe Leroy (CS GROUP)" , Ingo Molnar , Will Deacon , Waiman Long , Gary Guo , Alice Ryhl , Lyude Paul , Daniel Almeida , Onur =?iso-8859-1?Q?=D6zkan?= , Miguel Ojeda , Danilo Krummrich , linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Heiko Carstens Subject: Re: [PATCH v4 12/17] s390/preempt: Enable HAS_SEPARATE_PREEMPT_RESCHED_BITS Message-ID: <20260805094219.GM687043@noisy.programming.kicks-ass.net> References: <20260804161447.84806-1-boqun@kernel.org> <20260804161447.84806-13-boqun@kernel.org> <367a9709-eb79-4579-9405-fb8d89576413@linux.ibm.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <367a9709-eb79-4579-9405-fb8d89576413@linux.ibm.com> On Wed, Aug 05, 2026 at 01:57:04AM +0530, Shrikanth Hegde wrote: > +maddy, christophe, > > On 8/4/26 9:44 PM, Boqun Feng wrote: > > From: Heiko Carstens > > > > Convert s390's preempt_count to 64 bit, and change the preempt > > primitives accordingly. > > > > > + union { > > + struct { > > + __u32 need_resched; /* 0x03a8 */ > > + __u32 count; /* 0x03ac */ > > + } preempt; > > + __u64 preempt_count; /* 0x03a8 */ > > + }; > > > This is interesting. So arm64, s390 will have similar implementation > w.r.t to preempt_count. > > I guess PoC that i was trying for ppc64 is worth pursuing even more, > since ppc64 is one missing major arch which still uses old method > of querying tif_need_resched. > With similar change ppc64 can set HAS_SEPARATE_PREEMPT_RESCHED_BITS too. Yes. PPC should be able to the same thing ARM64 does.