From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-174.mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) (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 6827730FC03 for ; Thu, 23 Jul 2026 03:08:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784776120; cv=none; b=i3LLcluWl1gJYt2yAU0zklOq0XgVvaKpLkdSxk53HZj2/8iaqh6LWdYj+5/pSRl+oHxIkToTWkH473R7HhdqhTRQlRMxbAqUxvzO2DsUP4qXZR9F4SaL5+Ew5VdyB9fr9ovqh3lYWHdDxnPT+Y2wBsKte/MYPcouKozkR6KjBW8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784776120; c=relaxed/simple; bh=s8LnZUbjoE9QnnyHodHKbhombZZlRKh47j/BCZWnPiM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gwa+hiPQI144ggUSP+necC25p6DIZ2bqTvk1KFU6ioMv3F7QcDyiJxyiz9d+RZbEZpVIO1t4DMjNKPSdoAQmDOD9cMHY5hB7X0EYFqgnRaE4tvGtt+lQAH3tWvItHWcMB7GBaaTIz81zopoWw2SZV49JexLJsa4eKqQFaX0FWK0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=IAemcC5L; arc=none smtp.client-ip=91.218.175.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="IAemcC5L" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784776116; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CPn+6PAbSUYy39pblfECZc7kLKlZRJn3Dc36PYNt1tA=; b=IAemcC5LbRot2vZtr/G6azzKBwifUlE6e8OYKzasZZhv9sJZRcLA6xQtRGjTr8jvr6s1L3 W2XsYO+04T/tSF73omVbfY9ZtQxhu68Qmlm9yNVtvPzo4lHySl1zavuR42tnwurdFQnXXx CtuWJOEOLGKgtA0obNbrRKlJoySFFdo= From: Hongfu Li To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, hongfu.li@linux.dev, Hongfu Li Subject: [PATCH v2 2/2] mm: Extract non-swap page handling to do_non_swap_page() Date: Thu, 23 Jul 2026 11:07:52 +0800 Message-ID: <20260723030752.16979-3-hongfu.li@linux.dev> In-Reply-To: <20260723030752.16979-1-hongfu.li@linux.dev> References: <20260723030752.16979-1-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-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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 --- 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