PageTrans* helpers are always-false if THP is disabled compile-time. It means the fucntion will fail to detect hugetlb pages in this case.
Let's use PageCompound() instead. With small tweak to how we calculate next low_pfn it will make function ready to see tail pages. Signed-off-by: Kirill A. Shutemov <[email protected]> --- mm/compaction.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/mm/compaction.c b/mm/compaction.c index 018f08da99a2..6ef2fdf1d6b6 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -732,18 +732,18 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, * splitting and collapsing (collapsing has already happened * if PageLRU is set) but the lock is not necessarily taken * here and it is wasteful to take it just to check transhuge. - * Check TransHuge without lock and skip the whole pageblock if - * it's either a transhuge or hugetlbfs page, as calling + * Check PageCompound without lock and skip the whole pageblock + * if it's either a transhuge or hugetlbfs page, as calling * compound_order() without preventing THP from splitting the * page underneath us may return surprising results. */ - if (PageTransHuge(page)) { - if (!locked) - low_pfn = ALIGN(low_pfn + 1, - pageblock_nr_pages) - 1; + if (PageCompound(page)) { + int nr; + if (locked) + nr = 1 << compound_order(page); else - low_pfn += (1 << compound_order(page)) - 1; - + nr = pageblock_nr_pages; + low_pfn = ALIGN(low_pfn + 1, nr) - 1; continue; } @@ -763,11 +763,12 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, if (!locked) break; - /* Recheck PageLRU and PageTransHuge under lock */ + /* Recheck PageLRU and PageCompound under lock */ if (!PageLRU(page)) continue; - if (PageTransHuge(page)) { - low_pfn += (1 << compound_order(page)) - 1; + if (PageCompound(page)) { + int nr = 1 << compound_order(page); + low_pfn = ALIGN(low_pfn + 1, nr) - 1; continue; } } @@ -778,7 +779,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, if (__isolate_lru_page(page, isolate_mode) != 0) continue; - VM_BUG_ON_PAGE(PageTransCompound(page), page); + VM_BUG_ON_PAGE(PageCompound(page), page); /* Successfully isolated */ del_page_from_lru_list(page, lruvec, page_lru(page)); -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
