From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) (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 885C914A4F0 for ; Wed, 5 Aug 2026 11:03:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785927819; cv=none; b=uC58VNx+gz+g2Ews4fx1WOzOL8bFzTqwzNcVulHmrZrn9cbBLboF5gVHYsGH6oI6NIwsK1CHB6wn2pt7DYRPuVROhgZL8EGgDjjWMz2Twho2tHSsiwj8YKIV+a/FBhu8dm84uJ8sggCzBFuAInXJ2a9sQy+XZIYOkTIHQPfKu08= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785927819; c=relaxed/simple; bh=QZ6lKvnhbVeHlU6U3SVBxx8dvMrA3U0MLhqi1maPH58=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=rPwFYMYJwnptVfIgcwwvZ7ToHNgwsK/ePhQmjgjM8a8g+nYN/kEHHillNzSVN5ShTuPFyUa68OcoViSZz7jkRbtV5KDmZ2hhidT5NU25J5Q0pEINTaNcyXnY/awmAx7e5g6x16SP35utt5bJOSWZKmlIwJvFk/cXyBzios+6BKQ= 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=kL+KaXLl; arc=none smtp.client-ip=91.218.175.172 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="kL+KaXLl" 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=1785927815; 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; bh=R4TrMHTQkzwP2lLEW0oUQVcx04oxAW8/FB2AgqPWE68=; b=kL+KaXLlSRmxOZd41Q1d8l4/jqKr/ZYm47f8yzGu5BEqF2e7C/vKuZMbvHXlQuuRSPGY2M J1zxCBSaVEnGrZC13ujg9FxHZbJq54bTXDPFHy9chloV7JQhfuX3/rvWWiKpxzJr7tXl1y JzAC1N9VfGWtT+BtcVWNy9B6T7mYDaM= From: Hongfu Li To: akpm@linux-foundation.org, david@kernel.org, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, corbet@lwn.net, skhan@linuxfoundation.org, alexs@kernel.org, si.yanteng@linux.dev, dzm91@hust.edu.cn Cc: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, hongfu.li@linux.dev, Hongfu Li Subject: [PATCH] ksm: update comments and docs to reference folio->mapping Date: Wed, 5 Aug 2026 18:59:07 +0800 Message-ID: <20260805105927.41987-1-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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Hongfu Li The KSM code already stores and checks the stable node key via folio->mapping, but the comment in ksm_get_folio() and the reverse mapping documentation in ksm.rst still refer to page->mapping. This is a pure wording update to match the folio-based implementation. No functional change is intended. Signed-off-by: Hongfu Li --- Documentation/mm/ksm.rst | 4 ++-- Documentation/translations/zh_CN/mm/ksm.rst | 4 ++-- mm/ksm.c | 7 +++---- 3 files changed, 7 insertions(+), 8 deletions(-) diff --git a/Documentation/mm/ksm.rst b/Documentation/mm/ksm.rst index 2806e3e4a10e..2b4f72f1f953 100644 --- a/Documentation/mm/ksm.rst +++ b/Documentation/mm/ksm.rst @@ -24,13 +24,13 @@ tree. If a KSM page is shared between less than ``max_page_sharing`` VMAs, the node of the stable tree that represents such KSM page points to a -list of struct ksm_rmap_item and the ``page->mapping`` of the +list of struct ksm_rmap_item and the ``folio->mapping`` of the KSM page points to the stable tree node. When the sharing passes this threshold, KSM adds a second dimension to the stable tree. The tree node becomes a "chain" that links one or more "dups". Each "dup" keeps reverse mapping information for a KSM -page with ``page->mapping`` pointing to that "dup". +page with ``folio->mapping`` pointing to that "dup". Every "chain" and all "dups" linked into a "chain" enforce the invariant that they represent the same write protected memory content, diff --git a/Documentation/translations/zh_CN/mm/ksm.rst b/Documentation/translations/zh_CN/mm/ksm.rst index f0f458753d0c..822c7a289671 100644 --- a/Documentation/translations/zh_CN/mm/ksm.rst +++ b/Documentation/translations/zh_CN/mm/ksm.rst @@ -31,10 +31,10 @@ KSM维护着稳定树中的KSM页的逆映射信息。 当KSM页面的共享数小于 ``max_page_sharing`` 的虚拟内存区域(VMAs)时，则代表了 KSM页的稳定树其中的节点指向了一个ksm_rmap_item结构体类型的列表。同时，这个KSM页 -的 ``page->mapping`` 指向了该稳定树节点。 +的 ``folio->mapping`` 指向了该稳定树节点。 如果共享数超过了阈值，KSM将给稳定树添加第二个维度。稳定树就变成链接一个或多 -个稳定树"副本"的"链"。每个副本都保留KSM页的逆映射信息，其中 ``page->mapping`` +个稳定树"副本"的"链"。每个副本都保留KSM页的逆映射信息，其中 ``folio->mapping`` 指向该"副本"。 每个链以及链接到该链中的所有"副本"强制不变的是，它们代表了相同的写保护内存 diff --git a/mm/ksm.c b/mm/ksm.c index ab1fc59424e8..4bde9fd8d44e 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -959,10 +959,9 @@ enum ksm_get_folio_flags { * seconds or even minutes: much too unresponsive. So instead we use a * "keyhole reference": access to the ksm page from the stable node peeps * out through its keyhole to see if that page still holds the right key, - * pointing back to this stable node. This relies on freeing a PageAnon - * page to reset its page->mapping to NULL, and relies on no other use of - * a page to put something that might look like our key in page->mapping. - * is on its way to being freed; but it is an anomaly to bear in mind. + * pointing back to this stable node. This relies on freeing an anon + * folio to reset its mapping to NULL, and relies on no other use of a + * folio to put something that might look like our key in its mapping. */ static struct folio *ksm_get_folio(struct ksm_stable_node *stable_node, enum ksm_get_folio_flags flags) -- 2.54.0