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 E5B4941F5DB for ; Mon, 27 Jul 2026 16:31:07 +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=1785169869; cv=none; b=AI+ANrUDe25+xX1xgQleM+8ySiT/AON5sLJsazTj10Nx3T+YNm++GPsZBfCgSupdZdMH00IkqVOq4fa2gIkWpq2L5Nkxa+2FRUdhrUR9MBJgCXJmJ8Q40o7xR4EuCWNJmlbochunes/y7dLDB/wzqOwdrPkBw8cTt5VEp5qCEsM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785169869; c=relaxed/simple; bh=LhGkF78h7PmxGkRlk0mAygQ9PDoTQbCe+DecVfXRB08=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NQfflxDLlA3Urf/QRfmGQ49E4/an2yMdUp3uJq5GYeb5FB8lyhSD0kgyKrQytmz1uNtivsEmN4dVEgpBDcHG9lAFj2hsgKdEKmLnYW0UpSzNBktKiv5lj6PQ7Qhr1633DMa+qP73GJEFJxMJCoAUTpUDxh/uQ7K+/07VKT6m56o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ei438QZP; 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="Ei438QZP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E6381F000E9; Mon, 27 Jul 2026 16:31:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785169867; bh=xD3dgh+LvUBXuj8H0JRUqv8XiAhtAquDiwD9DIx7mY8=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Ei438QZPhoA/j4TNX5sKSZg5DC94anuXDfwoCs3yZ2nJ1Oo93Z8QUJh0hP+z8jZfx mvDvVMgJYsQ8OLdhMamWwAEZDxoj7gyp4EdbNObTpzy9Bg8USo+npPQAQuMCrN/RRx 58Vb14FKQ+pq8lMWh+GJn5EmAzsQrh7qEucJJNxVf3Rq9Q7MAf/oi7JVeOJtdxjOEV QGnVdcagw3jrjs8gqu7q4xY4E5RkSpPAS2vNOoRYOcqHrN8lM4/EMdx5XhG48/rkwa vrY1+iC3yvCIF7sDeFCS3a17J0J76nGjnXB+FGLpElE1FKSfCksjfAo8RNZq/teTMr UAgmKCVERFOAQ== Date: Mon, 27 Jul 2026 17:30:51 +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 2/2] mm: Extract non-swap page handling to do_non_swap_page() Message-ID: References: <20260723030752.16979-1-hongfu.li@linux.dev> <20260723030752.16979-3-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: <20260723030752.16979-3-hongfu.li@linux.dev> On Thu, Jul 23, 2026 at 11:07:52AM +0800, Hongfu Li wrote: > From: Hongfu Li > > Factor non-swap entry logic out of bloated do_swap_page() to simplify > the main swap fault flow and improve readability. > > The new do_non_swap_page() handles migration, device private/exclusive, > hwpoison, marker and bad PTE entries. > > Signed-off-by: Hongfu Li We've already gone over this elsewhere in the thread, we don't want a do_non_swap_page() (HELL no). But in general I want to finish what I started with softleaves, which still has some work to do with swap entries so maybe could you just drop this patch so I can follow up with that later? That way you can do a respin of just the 1/2 as a v3. Thanks, Lorenzo > --- > mm/memory.c | 120 ++++++++++++++++++++++++++++++---------------------- > 1 file changed, 69 insertions(+), 51 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index ae521baa8c84..50d8e92aef91 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4815,6 +4815,74 @@ static void check_swap_exclusive(struct folio *folio, swp_entry_t entry, > } while (--nr_pages); > } > > +static vm_fault_t do_non_swap_page(struct vm_fault *vmf) > +{ > + struct vm_area_struct *vma = vmf->vma; > + struct folio *folio; > + softleaf_t entry; > + vm_fault_t ret = 0; > + > + entry = softleaf_from_pte(vmf->orig_pte); > + if (softleaf_is_migration(entry)) { > + migration_entry_wait(vma->vm_mm, vmf->pmd, > + vmf->address); > + } else if (softleaf_is_device_exclusive(entry)) { > + vmf->page = softleaf_to_page(entry); > + ret = remove_device_exclusive_entry(vmf); > + } else if (softleaf_is_device_private(entry)) { > + > + if (vmf->flags & FAULT_FLAG_VMA_LOCK) { > + /* > + * migrate_to_ram is not yet ready to operate > + * under VMA lock. > + */ > + vma_end_read(vma); > + return VM_FAULT_RETRY; > + } > + > + 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))) > + goto unlock; > + > + /* > + * Get a folio reference while we know the folio can't be > + * freed. > + */ > + folio = page_folio(vmf->page); > + if (folio_trylock(folio)) { > + struct dev_pagemap *pgmap; > + > + folio_get(folio); > + pte_unmap_unlock(vmf->pte, vmf->ptl); > + pgmap = page_pgmap(vmf->page); > + ret = pgmap->ops->migrate_to_ram(vmf); > + folio_unlock(folio); > + folio_put(folio); > + } else { > + pte_unmap(vmf->pte); > + softleaf_entry_wait_on_locked(entry, vmf->ptl); > + } > + } else if (softleaf_is_hwpoison(entry)) { > + ret = VM_FAULT_HWPOISON; > + } else if (softleaf_is_marker(entry)) { > + ret = handle_pte_marker(vmf); > + } else { > + print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); > + ret = VM_FAULT_SIGBUS; > + } > + > + return ret; > + > +unlock: > + if (vmf->pte) > + pte_unmap_unlock(vmf->pte, vmf->ptl); > + return ret; > +} > + > /* > * We enter with either the VMA lock or the mmap_lock held (see > * FAULT_FLAG_VMA_LOCK), and pte mapped but not yet locked. > @@ -4845,57 +4913,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) > > entry = softleaf_from_pte(vmf->orig_pte); > if (unlikely(!softleaf_is_swap(entry))) { > - if (softleaf_is_migration(entry)) { > - migration_entry_wait(vma->vm_mm, vmf->pmd, > - vmf->address); > - } else if (softleaf_is_device_exclusive(entry)) { > - vmf->page = softleaf_to_page(entry); > - ret = remove_device_exclusive_entry(vmf); > - } else if (softleaf_is_device_private(entry)) { > - if (vmf->flags & FAULT_FLAG_VMA_LOCK) { > - /* > - * migrate_to_ram is not yet ready to operate > - * under VMA lock. > - */ > - vma_end_read(vma); > - ret = VM_FAULT_RETRY; > - goto out; > - } > - > - 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))) > - goto unlock; > - > - /* > - * Get a folio reference while we know the folio can't be > - * freed. > - */ > - folio = page_folio(vmf->page); > - if (folio_trylock(folio)) { > - struct dev_pagemap *pgmap; > - > - folio_get(folio); > - pte_unmap_unlock(vmf->pte, vmf->ptl); > - pgmap = page_pgmap(vmf->page); > - ret = pgmap->ops->migrate_to_ram(vmf); > - folio_unlock(folio); > - folio_put(folio); > - } else { > - pte_unmap(vmf->pte); > - softleaf_entry_wait_on_locked(entry, vmf->ptl); > - } > - } else if (softleaf_is_hwpoison(entry)) { > - ret = VM_FAULT_HWPOISON; > - } else if (softleaf_is_marker(entry)) { > - ret = handle_pte_marker(vmf); > - } else { > - print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL); > - ret = VM_FAULT_SIGBUS; > - } > + ret = do_non_swap_page(vmf); > goto out; > } > > -- > 2.54.0 >