From patchwork Mon Feb 10 19:37:56 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 13968990 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 2B9182505A8 for ; Mon, 10 Feb 2025 19:39:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739216342; cv=none; b=EQxdPWqoo1C3zKSoCcIWaIjC42oJpPmYQDuc8B95QhV/AmbfPmynqAXmiivHiiUWU/YzZTbWu9/DH7TGwxH8F4n30Zrd857lwGhcak/sZtOd59yy3pNXxLaVKH/LCrpSkIbOCf0BQB6VOiLx0XUNU/L7xhCEJNS6ycvwMJvWwAo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739216342; c=relaxed/simple; bh=xdb/Bd8nabay5U0SQXbchR0hBzNIzuX4jtY3vE4Olv8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:content-type; b=iHMudYlmvh/Hi79pnnaB9TvAxfZzNiIOKyPBOyQTvQyTUtxBejgMcYqgT/WqGJ9k8B+QBk7i1G+QNXNW4Cwh3mFY8xqBRM2Vqgw/3qZ92s2BS2lFgbFzKFpQYtw0ZLHS0CA74aIX2vR7jBF5cBFsHha9mmyCzK09baZCjg6gW3k= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=HENOEqYW; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HENOEqYW" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1739216340; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oE9Ja/aC61CHup4qeT96Odiagg40Q7TPEFXRUvHwXRo=; b=HENOEqYW23FVkl2qDgOt1R9Yb2YQsPWKLOM7RE3Lz48FdX4WK6IjmMjQ3pPwnpSTyXYDuf w7jBnPIHOaeceoQaNQSfuxT7dsFlYfyy3jzEx0zmDHeAk5kH6M+hYBFq0RurpIBcTjw23V EHg3DsgrXoTX+ZQ2e/tGel8oyacktDM= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-447-9bPCQyu_NMyZHg0ZssKrWQ-1; Mon, 10 Feb 2025 14:38:59 -0500 X-MC-Unique: 9bPCQyu_NMyZHg0ZssKrWQ-1 X-Mimecast-MFC-AGG-ID: 9bPCQyu_NMyZHg0ZssKrWQ Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-38dc709f938so1785941f8f.0 for ; Mon, 10 Feb 2025 11:38:58 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1739216338; x=1739821138; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=oE9Ja/aC61CHup4qeT96Odiagg40Q7TPEFXRUvHwXRo=; b=BQszKyd170cZYcJf83ZYziBJOXs0sd2eXykzsdRcPihNQSTXf3s70Vihjx3jk5Lbrh 6WKbruh98OOtiV+X1J+zQK1Pm6NAk+MS2IKRvfOFsHQlQ/HgPft8CbjkSBXG2zWssKNV Xws+iEYKAF2DY2A/jml3+c1UlinPjx6XZAhKPytSsXnll5801xWKt/5nRj7erHomkQa+ BP02fgaqIYxUYsmqvGhmAc4JunSzYld4UioTMTRAlAza+zn9GbEuHNvabocrTPtG4zUD SAI/DDnmLWtZEqywzX5k3XlPKn+bO5Byhq4hveIm1xhlZi8GFp5bzW5kDgL0NAj5vWy/ GY4w== X-Forwarded-Encrypted: i=1; AJvYcCV6eDn7OevGkGIoIjPqlzmf3uPPjAfCEznYtjgBKNojpYLbMxyrN+Z0CaV2bmk3QGPvNO3qP1PUjNoYXCUVgi757FA=@vger.kernel.org X-Gm-Message-State: AOJu0YzubdRyYlkFvJ09bBGLgUcclIzBYViN5/wflvO5LGRHwm+lgwk9 8V/jxZgqRJt+AuaAqwl0YP63QjKYMPPktO7SR7ggJWsKpOdJk1YxqIUFLubjlhLv66n3T9QxBkx 4N2956DCI3WO3NLnTb3gPg3BtRka/uOYGZEBDEZhatJtQFD2OKgZGxvysPtSby041hJJQhQ== X-Gm-Gg: ASbGncsQJNQcw9cBjrb+Z0RrsSVE0BEnRFr6RD/aZzK0dUwCw9vK9MxWqGR8OOC+3Z3 8/XAJa5VoLhf/dvbNEcdiazOpfgN6PQxHvWYJnECPBMTL8bDOpt0/OfT46G7hUc7AhWXAhfy0CH ynAp7UHY4YqetXpIhIcthhPR66TFLXJNlJ89PVeUqiHeSsGtqrcnRMakoyXtd+/wExVkc1IxP8p nbvjcxpBLH7a5LfDmTsEz6BjrDCeYm8j1+XTsh55QLqkz0+YLZ9DCLZbLKvCfB3658i7610b67n JnpZzGhYEirTxzyZi/cW7q26roKiYY84iMZvxcQGv1H22R5hTvBU3OvRBGHYw3qK3A== X-Received: by 2002:a05:6000:1887:b0:38b:f4e6:21aa with SMTP id ffacd0b85a97d-38de439b7e5mr512530f8f.5.1739216337879; Mon, 10 Feb 2025 11:38:57 -0800 (PST) X-Google-Smtp-Source: AGHT+IF/uzgNmJSm7r4vj5m1RC+0Hk4d4M8qsuHzJI2p/6gaMOev6b/snbfbww+U3ctbsFbws8/HTA== X-Received: by 2002:a05:6000:1887:b0:38b:f4e6:21aa with SMTP id ffacd0b85a97d-38de439b7e5mr512516f8f.5.1739216337518; Mon, 10 Feb 2025 11:38:57 -0800 (PST) Received: from localhost (p200300cbc734b80012c465cd348aaee6.dip0.t-ipconnect.de. [2003:cb:c734:b800:12c4:65cd:348a:aee6]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-38dcc9bd251sm9816921f8f.9.2025.02.10.11.38.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 10 Feb 2025 11:38:56 -0800 (PST) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-doc@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-mm@kvack.org, nouveau@lists.freedesktop.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, damon@lists.linux.dev, David Hildenbrand , Andrew Morton , =?utf-8?b?SsOpcsO0bWUgR2xpc3Nl?= , Jonathan Corbet , Alex Shi , Yanteng Si , Karol Herbst , Lyude Paul , Danilo Krummrich , David Airlie , Simona Vetter , Masami Hiramatsu , Oleg Nesterov , Peter Zijlstra , SeongJae Park , "Liam R. Howlett" , Lorenzo Stoakes , Vlastimil Babka , Jann Horn , Pasha Tatashin , Peter Xu , Alistair Popple , Jason Gunthorpe Subject: [PATCH v2 14/17] mm/damon: handle device-exclusive entries correctly in damon_folio_young_one() Date: Mon, 10 Feb 2025 20:37:56 +0100 Message-ID: <20250210193801.781278-15-david@redhat.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250210193801.781278-1-david@redhat.com> References: <20250210193801.781278-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: YJUsLkHCGBoG1cNoqx75xO6AVxqxZ3j6POs9H-dnZV0_1739216338 X-Mimecast-Originator: redhat.com content-type: text/plain; charset="US-ASCII"; x-default=true Ever since commit b756a3b5e7ea ("mm: device exclusive memory access") we can return with a device-exclusive entry from page_vma_mapped_walk(). damon_folio_young_one() is not prepared for that, so teach it about these PFN swap PTEs. Note that device-private entries are so far not applicable on that path, as we expect ZONE_DEVICE pages so far only in migration code when it comes to the RMAP. The impact is rather small: we'd be calling pte_young() on a non-present PTE, which is not really defined to have semantic. Note that we could currently only run into this case with device-exclusive entries on THPs. We still adjust the mapcount on conversion to device-exclusive; this makes the rmap walk abort early for small folios, because we'll always have !folio_mapped() with a single device-exclusive entry. We'll adjust the mapcount logic once all page_vma_mapped_walk() users can properly handle device-exclusive entries. Fixes: b756a3b5e7ea ("mm: device exclusive memory access") Signed-off-by: David Hildenbrand Reviewed-by: SeongJae Park --- mm/damon/paddr.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index 0f9ae14f884dd..10d75f9ceeafb 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -92,12 +92,20 @@ static bool damon_folio_young_one(struct folio *folio, { bool *accessed = arg; DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, addr, 0); + pte_t pte; *accessed = false; while (page_vma_mapped_walk(&pvmw)) { addr = pvmw.address; if (pvmw.pte) { - *accessed = pte_young(ptep_get(pvmw.pte)) || + pte = ptep_get(pvmw.pte); + + /* + * PFN swap PTEs, such as device-exclusive ones, that + * actually map pages are "old" from a CPU perspective. + * The MMU notifier takes care of any device aspects. + */ + *accessed = (pte_present(pte) && pte_young(pte)) || !folio_test_idle(folio) || mmu_notifier_test_young(vma->vm_mm, addr); } else {