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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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260731094054.90791-1-hongfu.li@linux.dev> X-Rspamd-Queue-Id: D29C81C000F X-Stat-Signature: i1ci7gfa4a8xnhkgmiocbiq11o1q9ehz X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1785503208-38331 X-HE-Meta: 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 vXJNUKpp qS6db73TzvAllFy55uGpInYs2ZN7yJmC7HDJYpem8NN/7oxLRZYUPIs0bFZMb3Jl/gQ9l8aNaAuOEefLquZir/8VLWkS/CH9tDWeGPztiS1w9idqqbaKavjnc+3YM40FqaFiuUwf5aFQnNLqScmfu7EqsgCWrP9RFT9+aI/QL9x1Yb41+4Gm118SQu+YmCjxx6Udku5H9ktS9Sd4l4xhGtByVrVUWjJF7wW2sBwe3WibDOqFCVhZao2YiEYJiyC9/yWPuQywcGbSW200vILP3XR0Rzxyo7NrTZNIeXMHgDIFq6Bg= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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