From 23baf831a32c04f9a968812511540b1b3e648bf5 Mon Sep 17 00:00:00 2001 From: Kirill A. Shutemov Date: Wed, 15 Mar 2023 14:31:33 +0300 Subject: mm, treewide: redefine MAX_ORDER sanely MAX_ORDER currently defined as number of orders page allocator supports: user can ask buddy allocator for page order between 0 and MAX_ORDER-1. This definition is counter-intuitive and lead to number of bugs all over the kernel. Change the definition of MAX_ORDER to be inclusive: the range of orders user can ask from buddy allocator is 0..MAX_ORDER now. [kirill@shutemov.name: fix min() warning] Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box [akpm@linux-foundation.org: fix another min_t warning] [kirill@shutemov.name: fixups per Zi Yan] Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name [akpm@linux-foundation.org: fix underlining in docs] Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/ Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Reviewed-by: Michael Ellerman [powerpc] Cc: "Kirill A. Shutemov" Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/compaction.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm/compaction.c') diff --git a/mm/compaction.c b/mm/compaction.c index 5a9501e0ae01..709136556b9e 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -583,7 +583,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc, if (PageCompound(page)) { const unsigned int order = compound_order(page); - if (likely(order < MAX_ORDER)) { + if (likely(order <= MAX_ORDER)) { blockpfn += (1UL << order) - 1; cursor += (1UL << order) - 1; } @@ -938,7 +938,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, * a valid page order. Consider only values in the * valid order range to prevent low_pfn overflow. */ - if (freepage_order > 0 && freepage_order < MAX_ORDER) + if (freepage_order > 0 && freepage_order <= MAX_ORDER) low_pfn += (1UL << freepage_order) - 1; continue; } @@ -954,7 +954,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, if (PageCompound(page) && !cc->alloc_contig) { const unsigned int order = compound_order(page); - if (likely(order < MAX_ORDER)) + if (likely(order <= MAX_ORDER)) low_pfn += (1UL << order) - 1; goto isolate_fail; } @@ -2124,7 +2124,7 @@ static enum compact_result __compact_finished(struct compact_control *cc) /* Direct compactor: Is a suitable page free? */ ret = COMPACT_NO_SUITABLE_PAGE; - for (order = cc->order; order < MAX_ORDER; order++) { + for (order = cc->order; order <= MAX_ORDER; order++) { struct free_area *area = &cc->zone->free_area[order]; bool can_steal; -- cgit v1.2.3