From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DF4E9C9832A for ; Sun, 27 Sep 2026 02:56:06 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4hspw92Hbdz30Vv; Sun, 27 Sep 2026 12:55:37 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip="2607:f8b0:4864:39::11" ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1790477737; cv=none; b=kSfeCoB4lkKO9X6cLEDZ3xxP4T2zDORSSmyz/5xCiRsUmZ3Xd/iOEU1xgyoRhibUORzvpPpt3/+NIYeaxx7t8Gy1OLLJ84lvy0u6R/Zi11AIhkLVgssaY/NfF5Qdu3b8GduLMpC1fLoa0KN3FPDCrjveooaIw99MUnKdou4LGmOmTQ5k89CoJqOo7V2m5MeLjJDLkGm9UoY+TpxFW4+GL2Scf/AU1NeC3c1QuwQr76nMYD/Bv0p1QsVY7yYzzDGnoHtrRylj73rrAkaQ4ymmT8XYx6OspIrrGY3yneLXuL02/Jy/lZNCffExZuFcTRzKY55WMPesk93z+kSUGNbRNQ== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1790477737; c=relaxed/relaxed; bh=vDyOFF6NxHUIale2EKP70eICKc/klrg6ENuabN+7zVI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TeHuz0W9QhrPugwAQELpYtpjFs8E3PHi15VnfQR+tGAaMLqydlsjWaozcmDKXveGqa90K3QTsr13nG6NATDaisks896ZUT2O2M7nRpjNEs6Hq3w0NjyMy3jnDqerLikKiGffrsoXl8uewuzVRIAA/ONgMcfunyZhHpGNkkZdD/ASMcmDs/SszZPbRhb2bk+33hHivBM9VgOonnfO4gOzeVyV+Til9zdOPM5L2y0+FTmITEam9X+wdlFi64joOH2BzRNa2968MG8jVWN3fBbRY//C6exk7e75qkwLuQ8RBb6t1k7hAd0ET+oUVD4yYjcbcg365k4Pb9XiJV3655zZPg== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com; dkim=pass (2048-bit key; unprotected) header.d=bytedance.com header.i=@bytedance.com header.a=rsa-sha256 header.s=google header.b=ZKhX9yOK; dkim-atps=neutral; spf=pass (client-ip=2607:f8b0:4864:39::11; helo=mail-pj2-x11.google.com; envelope-from=songmuchun@bytedance.com; receiver=lists.ozlabs.org) smtp.mailfrom=bytedance.com Authentication-Results: lists.ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=bytedance.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=bytedance.com header.i=@bytedance.com header.a=rsa-sha256 header.s=google header.b=ZKhX9yOK; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=bytedance.com (client-ip=2607:f8b0:4864:39::11; helo=mail-pj2-x11.google.com; envelope-from=songmuchun@bytedance.com; receiver=lists.ozlabs.org) Received: from mail-pj2-x11.google.com (mail-pj2-x11.google.com [IPv6:2607:f8b0:4864:39::11]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4hspw83GZtz3048 for ; Sun, 27 Sep 2026 12:55:36 +1000 (AEST) Received: by mail-pj2-x11.google.com with SMTP id 98e67ed59e1d1-39b5b07ec78so1082531a91.3 for ; Sat, 26 Sep 2026 19:55:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1790477735; x=1791082535; darn=lists.ozlabs.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=vDyOFF6NxHUIale2EKP70eICKc/klrg6ENuabN+7zVI=; b=ZKhX9yOKfiQxiTlr9XV2Trecqg+KxsYk4lUg02cykA95hUFOOqEMRhJlVf6BWbUwUf rg6poAhtV4E2FdcBzVxjXdXG0HO0gaQRQYX2Na3PyiF5YhmfXn80TLMoPVB4k4K0Oxwv o42b+gTg+ydHNq0zASvvi+UopogSVIQcB+c3gFQzQ409cKlpyNqRZ5iU79v+hsfEgMYp dzKltoH6qFJj/5CJK4KE+5oPC7SlC8UnMr2yXBJAXlROqKpjysmAmVai/NOUgBBMTdvp G0lZBsPCxWYIGfyO4rkkHPopEwlFWC/GoTA0LPYWIYY4rWZpdUPOIQ+TBJp6bzjbGq2Y MmZg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790477735; x=1791082535; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=vDyOFF6NxHUIale2EKP70eICKc/klrg6ENuabN+7zVI=; b=LjsBPOpz+Unfz3EjNmEWopCAzlMWxDKxPbtYSn/0ZNNJcI/ssW0CdRlE2NwhIHNkOL tklZ8wVdgd33wgSUlDNyCgAZVIdFC97oy4da5UT02wIQrdKzMsyBcfmCXdnTcvvskkLn 6TS4bp9vAEkEhHM9/XkKS3czh+2BkVNHil8/tY75i3AgvEhm+s46lFoTMF/KQnSAet0f 83YK3G8ZkmfqDkIbz/HrysE31U72Hv5lUMt0FY2uo5gDkc+uXK5Ahw5NFuGUJDispYP/ 8ZtrwnZKpBLuMcA7jcZ88QHX6LO/FxdCihntEen0jmiHdj5x97Cs+00LJdKFGa5sZR5I 3m/Q== X-Forwarded-Encrypted: i=1; AKwUvByTuaH5ScnPjKpWzwWVuqMigVqqsC2C2UeLgdCnRusalk6pEc008uK/BPk6+xVUemENDK3+iulckilJE/0=@lists.ozlabs.org X-Gm-Message-State: AFq9FYLF5jqWm60CsTx6odc026yYwDGEtOe4oUomwjnhS+WPoQhFP2no axXekG0m4NTolu6ijOOwS3YfNHLC4ULnLkMESorthH/9A1tSPFStCpksUq4DBeRuRKY= X-Gm-Gg: AYBFou0nCwZuJ6wbFrqOx5CJsTrwu/peFiGSHnmd3r1OsIwUobnPFYxX/tPEkmsA7Ek F4BPqjAmzwfV8trH4lXXxYQjnUdvHgtekMprWz1IXufNJqfzglKoCsDt/M+bcmloOqNluh25LMH fC5XOnMgX1b1/0Pu9P71mbmL8VFtinmJlbr9Janh6PnITbRpn6aSQLcFbQH5HJGOs9MFLAD1YBA HaxnxlkfmQFmd/o8C1ADCPtrdjAcD3OSHxD1Dj2RorJl4g0NRDkJytI1nt9TDFC5jFy+cTB6AhD WTQ0Mb9IzzEl3qLg/fAVTwXak9aRF4TtFOQqdQzMCoHtU9YoUSwCQJ5inxkXAt7n5qicK/oJ7uO WyYFfLG0LihmEZp6O6/zP47Q0Q3xxQRB8xz/dwQL4g8ZJtrfcqDp0yN1qmws7KF2xTD3bIbN+no Dn/ZgKCsuovR7LWtSmquAkL/GCw+z2qk6PyMBCUBhqpAsM6OlIQ+9JtGSyi3dfbQy5lQ3x+pKGt 1WybUJPSNssc12W208u X-Received: by 2002:a17:90b:51cb:b0:3a0:516d:9f87 with SMTP id 98e67ed59e1d1-3a0985710a5mr8073880a91.13.1790477734640; Sat, 26 Sep 2026 19:55:34 -0700 (PDT) Received: from n232-176-004.byted.org ([36.110.163.102]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3a0b8efb156sm13461377a91.1.2026.09.26.19.55.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 26 Sep 2026 19:55:34 -0700 (PDT) From: Muchun Song To: Andrew Morton , David Hildenbrand , Oscar Salvador , Madhavan Srinivasan , Michael Ellerman , Jonathan Corbet Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, Muchun Song , Lorenzo Stoakes , Mike Rapoport , Qi Zheng , Nicholas Piggin , Christophe Leroy , Randy Dunlap , Muchun Song , Lance Yang Subject: [PATCH v5 09/12] powerpc/mm: switch device DAX to shared tail vmemmap pages Date: Sun, 27 Sep 2026 10:54:38 +0800 Message-ID: <20260927025441.741633-10-songmuchun@bytedance.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260927025441.741633-1-songmuchun@bytedance.com> References: <20260927025441.741633-1-songmuchun@bytedance.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The powerpc radix compound vmemmap population path still finds a reusable tail page by walking the vmemmap page tables. Switch it to the common vmemmap_shared_tail_page() helper instead, so it can use the shared vmemmap page directly to simplify the code. This removes the powerpc-specific tail-page lookup and its fallback path and aligns the device DAX vmemmap optimization path with HugeTLB. Signed-off-by: Muchun Song --- arch/powerpc/mm/book3s64/radix_pgtable.c | 80 +++--------------------- include/linux/vmemmap-optimization.h | 6 ++ mm/sparse-vmemmap.c | 6 -- 3 files changed, 15 insertions(+), 77 deletions(-) diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c index cf692b2b5f7b..ee068f24a79f 100644 --- a/arch/powerpc/mm/book3s64/radix_pgtable.c +++ b/arch/powerpc/mm/book3s64/radix_pgtable.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include @@ -1250,59 +1251,6 @@ static pte_t * __meminit radix__vmemmap_populate_address(unsigned long addr, int return pte; } -static pte_t * __meminit vmemmap_compound_tail_page(unsigned long addr, - unsigned long pfn_offset, int node) -{ - pgd_t *pgd; - p4d_t *p4d; - pud_t *pud; - pmd_t *pmd; - pte_t *pte; - unsigned long map_addr; - - /* the second vmemmap page which we use for duplication */ - map_addr = addr - pfn_offset * sizeof(struct page) + PAGE_SIZE; - pgd = pgd_offset_k(map_addr); - p4d = p4d_offset(pgd, map_addr); - pud = vmemmap_pud_alloc(p4d, node, map_addr); - if (!pud) - return NULL; - pmd = vmemmap_pmd_alloc(pud, node, map_addr); - if (!pmd) - return NULL; - if (pmd_leaf(*pmd)) - /* - * The second page is mapped as a hugepage due to a nearby request. - * Force our mapping to page size without deduplication - */ - return NULL; - pte = vmemmap_pte_alloc(pmd, node, map_addr); - if (!pte) - return NULL; - /* - * Check if there exist a mapping to the left - */ - if (pte_none(*pte)) { - /* - * Populate the head page vmemmap page. - * It can fall in different pmd, hence - * vmemmap_populate_address() - */ - pte = radix__vmemmap_populate_address(map_addr - PAGE_SIZE, node, NULL, NULL); - if (!pte) - return NULL; - /* - * Populate the tail pages vmemmap page - */ - pte = radix__vmemmap_pte_populate(pmd, map_addr, node, NULL, NULL); - if (!pte) - return NULL; - vmemmap_verify(pte, node, map_addr, map_addr + PAGE_SIZE); - return pte; - } - return pte; -} - int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn, unsigned long start, unsigned long end, int node, @@ -1320,6 +1268,12 @@ int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn, pud_t *pud; pmd_t *pmd; pte_t *pte; + struct page *tail_page; + unsigned int order = pfn_to_section_compound_order(start_pfn); + + tail_page = vmemmap_shared_tail_page(order, device_zone(node)); + if (!tail_page) + return -ENOMEM; for (addr = start; addr < end; addr = next) { @@ -1349,10 +1303,9 @@ int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn, next = addr + PAGE_SIZE; continue; } else { - unsigned long nr_pages = pgmap_vmemmap_nr(pgmap); + unsigned long nr_pages = 1UL << order; unsigned long addr_pfn = page_to_pfn((struct page *)addr); unsigned long pfn_offset = addr_pfn - ALIGN_DOWN(addr_pfn, nr_pages); - pte_t *tail_page_pte; /* * if the address is aligned to huge page size it is the @@ -1377,23 +1330,8 @@ int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn, next = addr + 2 * PAGE_SIZE; continue; } - /* - * get the 2nd mapping details - * Also create it if that doesn't exist - */ - tail_page_pte = vmemmap_compound_tail_page(addr, pfn_offset, node); - if (!tail_page_pte) { - - pte = radix__vmemmap_pte_populate(pmd, addr, node, NULL, NULL); - if (!pte) - return -ENOMEM; - vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); - - next = addr + PAGE_SIZE; - continue; - } - pte = radix__vmemmap_pte_populate(pmd, addr, node, NULL, pte_page(*tail_page_pte)); + pte = radix__vmemmap_pte_populate(pmd, addr, node, NULL, tail_page); if (!pte) return -ENOMEM; vmemmap_verify(pte, node, addr, addr + PAGE_SIZE); diff --git a/include/linux/vmemmap-optimization.h b/include/linux/vmemmap-optimization.h index bd0974b262a4..fa9e9abd6656 100644 --- a/include/linux/vmemmap-optimization.h +++ b/include/linux/vmemmap-optimization.h @@ -83,6 +83,12 @@ static inline unsigned int pfn_to_section_compound_order(unsigned long pfn) { return 0; } + +static inline struct page *vmemmap_shared_tail_page(unsigned int order, + struct zone *zone) +{ + return NULL; +} #endif /* CONFIG_VMEMMAP_OPTIMIZATION */ static inline bool vmemmap_optimizable_pfn(unsigned long pfn) diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c index 2bc78aa053a1..4309f8b626f5 100644 --- a/mm/sparse-vmemmap.c +++ b/mm/sparse-vmemmap.c @@ -236,12 +236,6 @@ struct page __ref *vmemmap_shared_tail_page(unsigned int order, struct zone *zon return page; } -#else -static inline struct page *vmemmap_shared_tail_page(unsigned int order, - struct zone *zone) -{ - return NULL; -} #endif static __meminit void *vmemmap_alloc_pte(unsigned long pfn, int node, -- 2.54.0