From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 1DC4954654 for ; Tue, 30 Jun 2026 02:26:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782786365; cv=none; b=IL0L3WC1HVUUAWtaYVZx+YAlFWBiQ/gEZm+OkmWjLUfvt4SlCaO8u3dkQmH0e9zNCd+EZxWbLL5+xsrIFc5oLd5Zd9IcLLRMmgTFnyx5CePjy9Un+kWH9IfmHnBR+yxEYTFyCgVj3rQpRRyy5veHsV6lJcNr5aerprinU7685vw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782786365; c=relaxed/simple; bh=2ldF/tTNSuB0RjXw828mWCpmtjoSUJAfhtmzrNs7tMw=; h=Date:To:From:Subject:Message-Id; b=M5k5G14tryhQptQG2xUyymwRhQiTkWibEzFGHE2auA7qfYQCPuj5LyebA7VswfNzHj+pq6Qc2armo/hZNZFxasvvjgFRLoKewGWTjJMBUNO0gvA7gSBCAWzwZO/sb5Hx4tsJXkRUzylWk2cH0QF26Ndwb6qiixlVJnZ2TsI2hnE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=PHZ7yaf/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="PHZ7yaf/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B25CE1F000E9; Tue, 30 Jun 2026 02:26:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1782786363; bh=Jz0zHxxtgn/GQYdf7gVi5MzrG02hgr8MWbnCnJYh7sA=; h=Date:To:From:Subject; b=PHZ7yaf/3FJKpMF3PWnLnOWmMDcIE9vSM+YKBVoVClRi89446ge0uoXaDzuGirSK/ oyueEJbAmZzIi67vYTNZ6Oz8AyGqVss4NmGY9eeXpB2176fiMVpnvBPdQxT+apPRky HbFhA6Xn3R5Rrq0KYvJ060Ste7s4o+ujHwkPdrY4= Date: Mon, 29 Jun 2026 19:26:03 -0700 To: mm-commits@vger.kernel.org,ye.liu@linux.dev,akpm@linux-foundation.org From: Andrew Morton Subject: [to-be-updated] mm-page_owner-extract-skip_buddy_pages-helper-to-unify-buddy-page-skipping.patch removed from -mm tree Message-Id: <20260630022603.B25CE1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/page_owner: extract skip_buddy_pages() helper to unify buddy page skipping has been removed from the -mm tree. Its filename was mm-page_owner-extract-skip_buddy_pages-helper-to-unify-buddy-page-skipping.patch This patch was dropped because an updated version will be issued ------------------------------------------------------ From: Ye Liu Subject: mm/page_owner: extract skip_buddy_pages() helper to unify buddy page skipping Date: Fri, 26 Jun 2026 10:45:40 +0800 Patch series "mm/page_owner: misc cleanups", v2. This series collects a few cleanups for mm/page_owner.c that have been accumulated while reading through the file. There is no functional change -- the goal is to make the code easier to read and maintain. Patch 1 consolidates three identical PageBuddy skip blocks into a single skip_buddy_pages() helper, eliminating the duplication and keeping the lockless-read comment in one place. Patch 2 replaces the -1 magic number used for "never migrated" with a local MIGRATE_REASON_NONE define, making the intent explicit at every use site. Patch 3 hoists the CONFIG_MEMCG guard out of print_page_owner_memcg()'s body so that the real implementation and the empty stub are two clearly separate definitions, the common kernel idiom. Patch 4 adds a missing \n to the count_threshold debugfs attribute format string so that cat(1) output is properly terminated. Patch 5 moves free_ts_nsec from the allocation summary line to the free section in __dump_page_owner(), grouping it with free_pid and free_tgid where it logically belongs. This also makes the dump output consistent with print_page_owner(). Patch 6 drops the redundant page_owner_ prefix from file-scoped static symbols (stack_fops, threshold_fops, etc.). Since they cannot collide across translation units, the prefix carries no information. This patch (of 6): Three places in page_owner.c duplicate the same pattern: check if a page is PageBuddy, read its order via buddy_order_unsafe(), advance the pfn past the buddy block if the order is valid, and continue. Consolidate them into a single inline helper skip_buddy_pages(). The function returns true (skip) for any buddy page and advances @pfn past the block when the order is valid; returns false if the page is not a buddy page and should be processed normally. The old init_pages_in_zone() variant used "order > 0" as an extra guard before advancing pfn, but the continue was unconditional and (1UL << 0) - 1 == 0, so the behaviour is identical. The comment about zone->lock is preserved in the helper's kernel-doc. No functional change. Link: https://lore.kernel.org/20260626024550.25677-1-ye.liu@linux.dev Link: https://lore.kernel.org/20260626024550.25677-2-ye.liu@linux.dev Signed-off-by: Ye Liu Reviewed-by: Zi Yan Cc: Brendan Jackman Cc: Johannes Weiner Cc: Michal Hocko Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/page_owner.c | 52 +++++++++++++++++++++++----------------------- 1 file changed, 26 insertions(+), 26 deletions(-) --- a/mm/page_owner.c~mm-page_owner-extract-skip_buddy_pages-helper-to-unify-buddy-page-skipping +++ a/mm/page_owner.c @@ -422,6 +422,29 @@ void __folio_copy_owner(struct folio *ne rcu_read_unlock(); } +/* + * Check if a page is a buddy page and advance @pfn past the entire buddy block. + * This safely reads the buddy order without the zone lock, which may cause us + * to skip less than the full buddy block, but that is acceptable for page owner + * iteration purposes. + * + * Return: true if the page was skipped (caller should continue its loop), + * false if the page is not a buddy page and should be processed normally. + */ +static inline bool skip_buddy_pages(unsigned long *pfn, struct page *page) +{ + unsigned long order; + + if (!PageBuddy(page)) + return false; + + order = buddy_order_unsafe(page); + if (order <= MAX_PAGE_ORDER) + *pfn += (1UL << order) - 1; + + return true; +} + void pagetypeinfo_showmixedcount_print(struct seq_file *m, pg_data_t *pgdat, struct zone *zone) { @@ -461,14 +484,8 @@ void pagetypeinfo_showmixedcount_print(s if (page_zone(page) != zone) continue; - if (PageBuddy(page)) { - unsigned long freepage_order; - - freepage_order = buddy_order_unsafe(page); - if (freepage_order <= MAX_PAGE_ORDER) - pfn += (1UL << freepage_order) - 1; + if (skip_buddy_pages(&pfn, page)) continue; - } if (PageReserved(page)) continue; @@ -697,13 +714,8 @@ read_page_owner(struct file *file, char } page = pfn_to_page(pfn); - if (PageBuddy(page)) { - unsigned long freepage_order = buddy_order_unsafe(page); - - if (freepage_order <= MAX_PAGE_ORDER) - pfn += (1UL << freepage_order) - 1; + if (skip_buddy_pages(&pfn, page)) continue; - } page_ext = page_ext_get(page); if (unlikely(!page_ext)) @@ -798,20 +810,8 @@ static void init_pages_in_zone(struct zo if (page_zone(page) != zone) continue; - /* - * To avoid having to grab zone->lock, be a little - * careful when reading buddy page order. The only - * danger is that we skip too much and potentially miss - * some early allocated pages, which is better than - * heavy lock contention. - */ - if (PageBuddy(page)) { - unsigned long order = buddy_order_unsafe(page); - - if (order > 0 && order <= MAX_PAGE_ORDER) - pfn += (1UL << order) - 1; + if (skip_buddy_pages(&pfn, page)) continue; - } if (PageReserved(page)) continue; _ Patches currently in -mm which might be from ye.liu@linux.dev are mm-page_owner-use-migrate_reason_none-instead-of-1-for-last_migrate_reason.patch mm-page_owner-hoist-config_memcg-to-function-level-for-print_page_owner_memcg.patch mm-page_owner-add-missing-newline-to-count_threshold-format-string.patch mm-page_owner-move-free_ts_nsec-output-to-free-section-in-__dump_page_owner.patch mm-page_owner-drop-redundant-page_owner-prefix-from-static-symbols.patch mm-page_owner-clamp-skip_buddy_pages-pfn-advance-at-max_order_nr_pages-boundary.patch mm-page_owner-use-memcg_data-snapshot-instead-of-pagememcgkmem-to-avoid-toctou-vm_bug_on.patch