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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 111EFE937FC for ; Sun, 12 Apr 2026 19:00:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 786486B0088; Sun, 12 Apr 2026 15:00:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7372E6B00A2; Sun, 12 Apr 2026 15:00:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 625C56B00A4; Sun, 12 Apr 2026 15:00:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 4CEDD6B0088 for ; Sun, 12 Apr 2026 15:00:52 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 0FE058BBCE for ; Sun, 12 Apr 2026 19:00:52 +0000 (UTC) X-FDA: 84650820744.18.4B72EE4 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf25.hostedemail.com (Postfix) with ESMTP id 6847EA000E for ; Sun, 12 Apr 2026 19:00:50 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=pwkJzGsa; spf=pass (imf25.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776020450; a=rsa-sha256; cv=none; b=gcTO7jSzLNavaqQbm9WQXGE2NCWa9EqsOY4ZzqovzDYK6uUzJQ20lDeo7QsV4IG203XjKc 3yJYPPLz+QCYh0KEcKzVi/+eTrOXLNkjHEgKke8nWu4aUJznLJqJMu5IZSvhOqIBsc6gJG d0viTJhle9MPFkbsdLCSK+GnYH/qmWY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1776020450; h=from:from:sender: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:dkim-signature; bh=j92+OQ99Ybg09uFpo3hGXbK/dhlC/+hXdw1nkXJ7kic=; b=kem+jHmjpeyyrvlCaF8Co402ZbgaEQXH1x8nLZSpggRzeBO7tv8CDEbbCFVOsB5Lv16W5X D2EQMcehKMoNtXPwDiAV93gqgzK5WPdfMRkW+tOWdvlZnbNdLTnvHJLnkcofo4PORuR9kB eskKGVUvw714SUMHhL9pdWl7qOZmW2k= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=pwkJzGsa; spf=pass (imf25.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id EF0DF6132E; Sun, 12 Apr 2026 19:00:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A3CE0C19424; Sun, 12 Apr 2026 19:00:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776020449; bh=TsVZ6e4sn2FbkgFq2K8DRDubBw0VwKHbpvbtJYgoQ1Y=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=pwkJzGsayS+/jZo+nmmiIQrNnaxEr+SOQh4PaqC2CP88io1g96Coj60Z0D4Va39Xv NyZXxGz5tGTTYxsnqgOha8cYbv5sDXQlTLswIdukhw9BvLxMDR95awZ3m4a6UBGArO rPg/u3lq52tr12XFXLMEDB0DUSc2syhebLJfmO2XYVk+IHpKpxxqAhAU9oAZIU783o OHo/7Up+ti46w21INDiL1Ct4VP6JRvWvaPxOEzp6P+i7mqkiNBKoijbmul+ADOD5c3 nxxZXaNu8Dm36XbmFuRiFDbD87rSbhb8w2bKGvjCqcSsS/ZhvZ2LvbPxkd5lARvBS5 VW1YnArficdgw== From: "David Hildenbrand (Arm)" Date: Sun, 12 Apr 2026 20:59:39 +0200 Subject: [PATCH RFC 08/13] mm: re-consolidate folio->_entire_mapcount MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260412-mapcount-v1-8-05e8dfab52e0@kernel.org> References: <20260412-mapcount-v1-0-05e8dfab52e0@kernel.org> In-Reply-To: <20260412-mapcount-v1-0-05e8dfab52e0@kernel.org> To: Tejun Heo , Johannes Weiner , =?utf-8?q?Michal_Koutn=C3=BD?= , Jonathan Corbet , Shuah Khan , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Rik van Riel , Harry Yoo , Jann Horn , Brendan Jackman , Zi Yan , Pedro Falcato , Matthew Wilcox Cc: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, "David Hildenbrand (Arm)" X-Mailer: b4 0.13.0 X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 6847EA000E X-Stat-Signature: ifqfd5cesr7qjrho5g7fg1sg1ejpe3qq X-HE-Tag: 1776020450-318650 X-HE-Meta: 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 7hEtvf0E 4toIXW8oZuNYS285K3LNfaBshnru1BQ6/Wq+p+u1Yko29tsgKRGLtcVQY+P8UPlJ/tsEg+F9zkhC8cNEEneYnJKZzwcA5bb/qfb58yHAjpa6kXHSfLqrX0NvK6nR0RT4EQgoZ9WCUaXNTPA6sXp1WUm9e9Kw9USSOQfwd0tJjdbyDSmrF/Y2mTO+ZNmQ+tpIN+YxPo8O5MtAZA47bmD36ruJofvIMX8y9YCIVcNS3ecuBX/pAuqARdnW3wXKqm/Rx785n0cZDUZfplYQcD7xNRPqY0cZtD1xcIHEYsQv8MbtDoT73ZN1yxu4WqWDOTnnoPiMP Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Now that we have some space left in page[1] of a large folio on 32bit, we can re-consolidate folio->_entire_mapcount. Signed-off-by: David Hildenbrand (Arm) --- include/linux/mm.h | 4 +--- include/linux/mm_types.h | 5 ++--- mm/internal.h | 5 ++--- mm/page_alloc.c | 12 ++++-------- 4 files changed, 9 insertions(+), 17 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 633bbf9a184a..1715c6ed14d4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1832,9 +1832,7 @@ static inline int is_vmalloc_or_module_addr(const void *x) */ static inline int folio_entire_mapcount(const struct folio *folio) { - VM_BUG_ON_FOLIO(!folio_test_large(folio), folio); - if (!IS_ENABLED(CONFIG_64BIT) && unlikely(folio_large_order(folio) == 1)) - return 0; + VM_WARN_ON_FOLIO(!folio_test_large(folio), folio); return atomic_read(&folio->_entire_mapcount) + 1; } diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 47b2c3d05f41..1e1befe7d418 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -452,9 +452,9 @@ struct folio { struct { /* public: */ atomic_t _large_mapcount; - unsigned int _unused_1; -#ifdef CONFIG_64BIT atomic_t _entire_mapcount; +#ifdef CONFIG_64BIT + unsigned int _unused_1; atomic_t _pincount; #endif /* CONFIG_64BIT */ mm_id_mapcount_t _mm_id_mapcount[2]; @@ -483,7 +483,6 @@ struct folio { /* public: */ struct list_head _deferred_list; #ifndef CONFIG_64BIT - atomic_t _entire_mapcount; atomic_t _pincount; #endif /* !CONFIG_64BIT */ /* private: the union with struct page is transitional */ diff --git a/mm/internal.h b/mm/internal.h index 30e48f39d2de..53b20de141b9 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -868,10 +868,9 @@ static inline void prep_compound_head(struct page *page, unsigned int order) folio->_mm_id_mapcount[0] = -1; folio->_mm_id_mapcount[1] = -1; } - if (IS_ENABLED(CONFIG_64BIT) || order > 1) { + atomic_set(&folio->_entire_mapcount, -1); + if (IS_ENABLED(CONFIG_64BIT) || order > 1) atomic_set(&folio->_pincount, 0); - atomic_set(&folio->_entire_mapcount, -1); - } if (order > 1) INIT_LIST_HEAD(&folio->_deferred_list); } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8888f31aca49..1c09d79cade3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1121,11 +1121,11 @@ static int free_tail_page_prepare(struct page *head_page, struct page *page) goto out; } } + if (folio_entire_mapcount(folio)) { + bad_page(page, "nonzero entire_mapcount"); + goto out; + } if (IS_ENABLED(CONFIG_64BIT)) { - if (unlikely(atomic_read(&folio->_entire_mapcount) + 1)) { - bad_page(page, "nonzero entire_mapcount"); - goto out; - } if (unlikely(atomic_read(&folio->_pincount))) { bad_page(page, "nonzero pincount"); goto out; @@ -1139,10 +1139,6 @@ static int free_tail_page_prepare(struct page *head_page, struct page *page) goto out; } if (!IS_ENABLED(CONFIG_64BIT)) { - if (unlikely(atomic_read(&folio->_entire_mapcount) + 1)) { - bad_page(page, "nonzero entire_mapcount"); - goto out; - } if (unlikely(atomic_read(&folio->_pincount))) { bad_page(page, "nonzero pincount"); goto out; -- 2.43.0