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 4DB9648986F for ; Fri, 31 Jul 2026 13:06:48 +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=1785503209; cv=none; b=XJe1xUN3Brl6fZHpOs6eKyuYdLN61FvJbT+lbHUVk2jczPAiwhMU+Te35/v1yUdseEl8xVm4pZ8Lu1qG/Ido4CTdhiSHHYXaf+QGKUqVzYbuV2UL6WDVg+73jiLCG+k82RNU3xQSoBfo70x9z9Fsh2t5IrKeyi8LEnnbY9jiVuU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785503209; c=relaxed/simple; bh=SNPMwzkwLDhtU52fSePEzjFHnMTGdgqYSs16ZfzRrhQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pCTrDLEkWmMryzHuR8TnxVK8AEkTdvWh0bC1qmojXKU5Zz7P43wQIxdW5Y03j3EhaodR6oGEVvFyD4L1CXOeXPITyBDd1E/Xt/bII6n/8duz5LdujvRi5B7oa6ZtGcMwbM0n9tfcBkaO0cvT/QuUMfzviTquAdipT4L9YwK7IkI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UXETMweu; 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="UXETMweu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4219C1F000E9; Fri, 31 Jul 2026 13:06:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785503207; bh=DfKDQGcjC77lWhFDxxIUMTeu7Or4b1KfGKqTpcdoQtg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=UXETMweuKAHYqTuS5uRHtY5TtueyuIE2O+mlkmCM5dAvXTXYxgI1ETPQNCT1M5EL4 OC3gK19KAd+yn9fPRiK9bt/Hg3SCuZhDwBcU7SSJIq+PRhSga84nsg6WfoUw2D4E+4 tdABxNtLnEXvH8zLfIsu3jTPoAaWYDz6RkHFvKEKYHhS3hikmj1NpFa3tHfyrNOkdR mOfpnbqKVyGVQuTb99j0N1fYwHz/U6/Z3wKq67lc85OD4sQeUM78REpUGH6bjMMM+C aFgEnHL6c9WFS6RaACpUYG2wpumJlf4vouyLNPMKC/bKisz/Nsz2Q8HJMbrVA3b3B6 LY/TXXBhqkMGw== Date: Fri, 31 Jul 2026 14:06:30 +0100 From: "Lorenzo Stoakes (ARM)" To: Hongfu Li Cc: akpm@linux-foundation.org, david@kernel.org, liam@infradead.org, lihongfu@kylinos.cn, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, rppt@kernel.org, surenb@google.com, vbabka@kernel.org Subject: Re: [PATCH v2 1/2] mm: Use a folio in the softleaf_is_device_private path Message-ID: References: <20260731094054.90791-1-hongfu.li@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260731094054.90791-1-hongfu.li@linux.dev> On Fri, Jul 31, 2026 at 05:40:54PM +0800, Hongfu Li wrote: > > > mm/memory.c | 11 ++++++----- > > > 1 file changed, 6 insertions(+), 5 deletions(-) > > > > > > diff --git a/mm/memory.c b/mm/memory.c > > > index d5e87624f692..ae521baa8c84 100644 > > > --- a/mm/memory.c > > > +++ b/mm/memory.c > > > @@ -4871,18 +4871,19 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) > > > goto unlock; > > > > > > > Up here we have: > > > > vmf->page = softleaf_to_page(entry); > > vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, > > vmf->address, &vmf->ptl); > > if (unlikely(!vmf->pte || > > !pte_same(ptep_get(vmf->pte), > > vmf->orig_pte))) > > > > Since we're canonicalising to folio why not actually set folio using > > softleaf_to_folio()? > > > > So > > > > + folio = softleaf_to_folio(entry); > > - vmf->page = softleaf_to_page(entry); > > + vmf->page = &folio->page; > > > > This would also make more sense in your 2/2. But more on that in a sec. > > Thanks, I've thought through your suggestion carefully. > > Could entry reference a tail page of a folio here? > If so, softleaf_to_folio() retrieves the folio containing this page, > and vmf->page = &folio->page would point to the folio's head page, > which may not be correct. Yeah that's true! My bad, disregard that bit then :) > > Best regards, > Hongfu -- Cheers, Lorenzo