[RFC PATCH 05/15] mm/memory_hotplug: online pages at section size.
From: Zi Yan <hidden>
Date: 2021-08-05 19:04:03
Also in:
lkml
Subsystem:
memory hot(un)plug, memory management, the rest · Maintainers:
David Hildenbrand, Oscar Salvador, Andrew Morton, Linus Torvalds
From: Zi Yan <ziy@nvidia.com> When CONFIG_SET_MAX_ORDER is used, MAX_ORDER can be larger than section size. Holes can appear in hotplug memory chunks with size of 2^MAX_ORDER. Use PFN_SECTION_SHIFT (the order of section size) to limit hotplug memory size. Signed-off-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <redacted> Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/memory_hotplug.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 85029994a494..91ca751ac20c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c@@ -601,16 +601,16 @@ static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages) unsigned long pfn; /* - * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might - * decide to not expose all pages to the buddy (e.g., expose them + * Online the pages in PFN_SECTION_SHIFT aligned chunks. The callback + * might decide to not expose all pages to the buddy (e.g., expose them * later). We account all pages as being online and belonging to this * zone ("present"). * When using memmap_on_memory, the range might not be aligned to - * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect - * this and the first chunk to online will be pageblock_nr_pages. + * PAGES_PER_SECTION - 1, but section size aligned. __ffs() will detect + * this and the first chunk to online will be PAGES_PER_SECTION. */ for (pfn = start_pfn; pfn < end_pfn;) { - int order = min(MAX_ORDER - 1UL, __ffs(pfn)); + int order = min_t(unsigned long, PFN_SECTION_SHIFT, __ffs(pfn)); (*online_page_callback)(pfn_to_page(pfn), order); pfn += (1UL << order);
--
2.30.2