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 1723E32B9BB for ; Mon, 27 Jul 2026 16:29:49 +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=1785169791; cv=none; b=PxlxUKf7VXBRC8KUjNjMU1vwMNBkAsa/btEApYVhc9MZATOTGR8m+YDJ5gqw5TNwxGNfrv1SPPq/gf4aysXQD/As/B1hnUdmB+oMpawWrxQhPVyGellJ7QEbiTbxDmwGfabnNr6CyNeTj5Y6ExA/pR4kR7fa1PASYlQArlNE9Sk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785169791; c=relaxed/simple; bh=T73VVEXe2rq8KX+eY4tpeutePjN8nA0uDMT1kSxm8f4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=stI6LCHXKbeM2TWdP44eieDqo2c4gnjkl8VY/3hA9dzNR53iJoIZqG26YL156CSbjt34npxnO3fi7SZS90LeFEhgCg+bbGXX6Uz83M0fSWkPbp8nTpADtZg/JAE+c7nZDWdJ/a9z+MWOUOYRZQt/bVU6gCOgkfweibuPl0VVN6M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kw1AZvYl; 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="kw1AZvYl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78FBB1F000E9; Mon, 27 Jul 2026 16:29:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785169789; bh=barQc/nnGT6K9yO5qrPbNOA4nT34BHoggqlafqCfinU=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=kw1AZvYl9fsLLFDrf03thMZpapgwREV573+aQgtXJh/1L6MywmzdrV1OuJ7BHGQNH 8v5SgpSQfSOWTyOcwAMNseru5+3K6ksmtAzWkk8GpbPI8NNusgv492yCWXaaeuYUY8 rKsB43XM+GHowHoQOSxt9fdNDbtekWruf8UMGYefBB4paSz565+bNU/RMnhv9Ldwjc brX5s+dV2Nm+yBS5y6KTZLF6U+B3dD3TNe8Bp6CBYF8J0+80Ai9LK7K3WKu95nRtr5 d5yudcbvmB4UIQu6hbyjLzl7cZwBXn7TqxspmFCKLy9VpilG0EHAMDi/CpfJ/E8zBE Hft7HhitnW3gQ== Date: Mon, 27 Jul 2026 17:29:32 +0100 From: "Lorenzo Stoakes (ARM)" To: Hongfu Li Cc: akpm@linux-foundation.org, david@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hongfu Li Subject: Re: [PATCH v2 1/2] mm: Use a folio in the softleaf_is_device_private path Message-ID: References: <20260723030752.16979-1-hongfu.li@linux.dev> <20260723030752.16979-2-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: <20260723030752.16979-2-hongfu.li@linux.dev> On Thu, Jul 23, 2026 at 11:07:51AM +0800, Hongfu Li wrote: > From: Hongfu Li > > Use the folio APIs in the device_private migration path of do_swap_page(), > replacing four calls to compound_head() with one. > > Signed-off-by: Hongfu Li > Acked-by: David Hildenbrand (Arm) With changes below applied LGTM, so: Reviewed-by: Lorenzo Stoakes (ARM) > --- > 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. > /* > - * Get a page reference while we know the page can't be > + * Get a folio reference while we know the folio can't be NIT: be -> next line for 80 chars. > * freed. > */ > - if (trylock_page(vmf->page)) { > + folio = page_folio(vmf->page); > + if (folio_trylock(folio)) { > struct dev_pagemap *pgmap; > > - get_page(vmf->page); > + folio_get(folio); > pte_unmap_unlock(vmf->pte, vmf->ptl); > pgmap = page_pgmap(vmf->page); > ret = pgmap->ops->migrate_to_ram(vmf); > - unlock_page(vmf->page); > - put_page(vmf->page); > + folio_unlock(folio); > + folio_put(folio); > } else { > pte_unmap(vmf->pte); > softleaf_entry_wait_on_locked(entry, vmf->ptl); > -- > 2.54.0 > Thanks, Lorenzo