From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 7F4A430E0DC; Mon, 1 Jun 2026 09:36:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780306599; cv=none; b=m9SHyhqZSv/aa0VNG+Jrod7DYakR72BAJgi0EYwOd24Hb92nelzaICABiiOYio94jVzG+NOVpHOLgCu4GdimkzZBV9ruzxVs+FxpilIjZIOwOxPcgnC4BOtkWuoMdv+BIMYP1bmu4CZyk8tpaVPWlvGx8WHsMaPwYlpfaCogiZQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780306599; c=relaxed/simple; bh=OKQJ5h2ilWnqSM469omCurIeXicioGZrBscwMvVlK0w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kkjIs7LbKIKZWfvX5F8R7e2USrybvnsZ+MRjD8bPAbqV7BmA54h//RY1Pun/VmfZDUcdUVOc7x2JHRC3l/ypg7bqW2H+v9Fi8zI6wcXgxLjIfmH93MJIJXZQX4xZAKKP5+IB7MDENlYKB50FQhq3S0PmeILo1Iij2b1w9WkZmSQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UY86iIMc; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UY86iIMc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BF18F1F00893; Mon, 1 Jun 2026 09:36:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780306598; bh=Q964EmR1sb0D+k4HDOGBDHSQElTuA68Eo3PT6Fx+5JM=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=UY86iIMcGikyN9u59oMpD3SPoWCDezq083xPacS+VXEBGVM0Lf5REGc9Geud0VJMd wz5dPm+uXnDuXxLBZCE0sM5/ks5eENPD8c0ki6Ad0H1BjivPl3la7dVLMD28shem8B 9YyqNliA6iyYU3qZQsPzqxosOKnQuKz37S1O24AHoy8rl2UKjdLWMC8LlI6RiAnkmy nMmpe3XTaxZ0ql3iyP+uJIqh8J/aWVdijHVSnn9tMTcMeseOc9cYfvoxbusgwfN5TT FHSpcMGeULWL/66IrJQHtK4bgI9OOAKqSECrKDsm+XCANmsF35O697XETEu6ZhRhAt TTzrHtzvna0Yg== Date: Mon, 1 Jun 2026 10:36:33 +0100 From: Lorenzo Stoakes To: Alexander Gordeev Cc: "Oscar Salvador (SUSE)" , Andrew Morton , David Hildenbrand , Anshuman Khandual , Oscar Salvador , Wei Yang , linux-s390@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] mm/page_vma_mapped_walk: Use ptep_get_lockless() for lockless access Message-ID: References: <20260528075507.1821939-1-agordeev@linux.ibm.com> <07baafe4-7d1c-42b0-9103-3e5666770061-agordeev@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@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: <07baafe4-7d1c-42b0-9103-3e5666770061-agordeev@linux.ibm.com> On Thu, May 28, 2026 at 04:30:36PM +0200, Alexander Gordeev wrote: > On Thu, May 28, 2026 at 04:14:03PM +0200, Oscar Salvador (SUSE) wrote: > > On Thu, May 28, 2026 at 12:24:35PM +0100, Lorenzo Stoakes wrote: > > > On Thu, May 28, 2026 at 09:55:07AM +0200, Alexander Gordeev wrote: > > > > Switch from ptep_get() to ptep_get_lockless() accessor for > > > > PTE reads when no lock is taken. > > > > > > This is an insufficient commit message that's just saying what you're doing, > > > which isn't very useful. > > > > > > Please explain why you're doing this and what the benefit is please. > > > > Maybe something like > > > > "When not holding the lock, there is a chance that the pte gets modified > > under our feet, so we need to use the lockless API to make sure that > > the entries remain consistent during the read." > > I would gladly use this, if it makes sense for everyone. > > @Lorenzo? Sounds good to me! Thanks > > > Only arm64 makes use of it though, due to the contpte stuff and being > > unable to do it atomically. > > Thanks! > > > -- > > Oscar Salvador > > SUSE Labs Cheers, Lorenzo