From nobody Sun Feb 8 14:13:07 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B1FCE15F415 for ; Mon, 25 Mar 2024 12:46:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711370773; cv=none; b=l/GbINHMTjmqMOI5K/6jNeca7y96O+Chj2NC2NtJckvuVu4whntPythlzM8/uFcgyL9gHO3171R0eLgD8udXUBgMJK94gzwjsR2oQEHXxCSIwtb46b8v6MWDZY7+vgaWk87Kw3j7zOQz+DI/PHE1mLaiijSWvwmEg8w+M0+2qlI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711370773; c=relaxed/simple; bh=2lgvFI0wNn9RTCMEzEWib7Gn+j7luBL+Jg2E4ycFUf0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SWgE9qdurynx6NPs/pfwFQ5ZIdQCf9NUIMjv4tT2vtOd65vnepJ2PSHxyA05XLET7JzMJ0hyVnr7R6IRD3aSYfgyrahnNJbDQLczeY6L3Q1Cyq/fGiH1VadpKEiYS5IMPCMiE0bw2ZmlblRutMmzDKY0eRV65qiC3hhm2rh1uI4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Dz0MergX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Dz0MergX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40281C43390; Mon, 25 Mar 2024 12:46:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711370773; bh=2lgvFI0wNn9RTCMEzEWib7Gn+j7luBL+Jg2E4ycFUf0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Dz0MergXwbNpE5qypVG9l++oEAh9GgKrjYVi2WZATBEUMf/h2vvKvfWuuN2rYay9Q mvBr0LRQln4jeWSRsqlLU8WM7vzf95ttjzjXBJIPtHyIR8fB+mcbA6L6yjQILNW13E EGLVB0l5Zlthhdi3jucQwfl7boWT3sAKrIJNV9XNKm1YRkYBe9NGv019lOFQyoxQuA 1IBBuXPnLgXvLTeau3NR1///K8RNQnj6GrTVhWQbmN6pYAV+qwXdZ2HD5AKz62NVjT KcjwNL2irL8wTYaKKGnUMzndCBL9R0lq+wEpVRtUACFl77GcxTnbkuJk6hE9dx6Hwk JDbfAotIewksw== From: alexs@kernel.org To: Matthew Wilcox , Andrea Arcangeli , Izik Eidus , david@redhat.com, Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryncsn@gmail.com Cc: "Alex Shi (tencent)" , Hugh Dickins , Chris Wright Subject: [PATCH v3 10/14] mm/ksm: Convert stable_tree_search to use folio Date: Mon, 25 Mar 2024 20:48:57 +0800 Message-ID: <20240325124904.398913-11-alexs@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240325124904.398913-1-alexs@kernel.org> References: <20240325124904.398913-1-alexs@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Alex Shi (tencent)" Although, the func may pass a tail page to check its contents, but only single page exist in KSM stable tree, so we still can use folio in stable_tree_search() to save a few compound_head calls. Signed-off-by: Alex Shi (tencent) Cc: Izik Eidus Cc: Matthew Wilcox Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Chris Wright --- mm/ksm.c | 58 +++++++++++++++++++++++++++++--------------------------- 1 file changed, 30 insertions(+), 28 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index c2afe2f926db..e92445f29685 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1828,7 +1828,7 @@ static __always_inline void *chain(struct ksm_stable_= node **s_n_d, * This function returns the stable tree node of identical content if foun= d, * NULL otherwise. */ -static struct page *stable_tree_search(struct page *page) +static void *stable_tree_search(struct page *page) { int nid; struct rb_root *root; @@ -1836,28 +1836,30 @@ static struct page *stable_tree_search(struct page = *page) struct rb_node *parent; struct ksm_stable_node *stable_node, *stable_node_dup, *stable_node_any; struct ksm_stable_node *page_node; + struct folio *folio; =20 - page_node =3D page_stable_node(page); + folio =3D page_folio(page); + page_node =3D folio_stable_node(folio); if (page_node && page_node->head !=3D &migrate_nodes) { /* ksm page forked */ - get_page(page); - return page; + folio_get(folio); + return folio; } =20 - nid =3D get_kpfn_nid(page_to_pfn(page)); + nid =3D get_kpfn_nid(folio_pfn(folio)); root =3D root_stable_tree + nid; again: new =3D &root->rb_node; parent =3D NULL; =20 while (*new) { - struct page *tree_page; + struct folio *tree_folio; int ret; =20 cond_resched(); stable_node =3D rb_entry(*new, struct ksm_stable_node, node); stable_node_any =3D NULL; - tree_page =3D chain_prune(&stable_node_dup, &stable_node, root); + tree_folio =3D chain_prune(&stable_node_dup, &stable_node, root); /* * NOTE: stable_node may have been freed by * chain_prune() if the returned stable_node_dup is @@ -1891,11 +1893,11 @@ static struct page *stable_tree_search(struct page = *page) * write protected at all times. Any will work * fine to continue the walk. */ - tree_page =3D get_ksm_page(stable_node_any, - GET_KSM_PAGE_NOLOCK); + tree_folio =3D ksm_get_folio(stable_node_any, + GET_KSM_PAGE_NOLOCK); } VM_BUG_ON(!stable_node_dup ^ !!stable_node_any); - if (!tree_page) { + if (!tree_folio) { /* * If we walked over a stale stable_node, * get_ksm_page() will call rb_erase() and it @@ -1908,8 +1910,8 @@ static struct page *stable_tree_search(struct page *p= age) goto again; } =20 - ret =3D memcmp_pages(page, tree_page); - put_page(tree_page); + ret =3D memcmp_pages(page, &tree_folio->page); + folio_put(tree_folio); =20 parent =3D *new; if (ret < 0) @@ -1952,26 +1954,26 @@ static struct page *stable_tree_search(struct page = *page) * It would be more elegant to return stable_node * than kpage, but that involves more changes. */ - tree_page =3D get_ksm_page(stable_node_dup, - GET_KSM_PAGE_TRYLOCK); + tree_folio =3D ksm_get_folio(stable_node_dup, + GET_KSM_PAGE_TRYLOCK); =20 - if (PTR_ERR(tree_page) =3D=3D -EBUSY) + if (PTR_ERR(tree_folio) =3D=3D -EBUSY) return ERR_PTR(-EBUSY); =20 - if (unlikely(!tree_page)) + if (unlikely(!tree_folio)) /* * The tree may have been rebalanced, * so re-evaluate parent and new. */ goto again; - unlock_page(tree_page); + folio_unlock(tree_folio); =20 if (get_kpfn_nid(stable_node_dup->kpfn) !=3D NUMA(stable_node_dup->nid)) { - put_page(tree_page); + folio_put(tree_folio); goto replace; } - return tree_page; + return tree_folio; } } =20 @@ -1984,8 +1986,8 @@ static struct page *stable_tree_search(struct page *p= age) rb_insert_color(&page_node->node, root); out: if (is_page_sharing_candidate(page_node)) { - get_page(page); - return page; + folio_get(folio); + return folio; } else return NULL; =20 @@ -2010,12 +2012,12 @@ static struct page *stable_tree_search(struct page = *page) &page_node->node, root); if (is_page_sharing_candidate(page_node)) - get_page(page); + folio_get(folio); else - page =3D NULL; + folio =3D NULL; } else { rb_erase(&stable_node_dup->node, root); - page =3D NULL; + folio =3D NULL; } } else { VM_BUG_ON(!is_stable_node_chain(stable_node)); @@ -2026,16 +2028,16 @@ static struct page *stable_tree_search(struct page = *page) DO_NUMA(page_node->nid =3D nid); stable_node_chain_add_dup(page_node, stable_node); if (is_page_sharing_candidate(page_node)) - get_page(page); + folio_get(folio); else - page =3D NULL; + folio =3D NULL; } else { - page =3D NULL; + folio =3D NULL; } } stable_node_dup->head =3D &migrate_nodes; list_add(&stable_node_dup->list, stable_node_dup->head); - return page; + return folio; =20 chain_append: /* stable_node_dup could be null if it reached the limit */ --=20 2.43.0