From e496cf3d782135c1cca0d154d4b924517ff58de0 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Tue, 26 Jul 2016 15:26:35 -0700 Subject: thp: introduce CONFIG_TRANSPARENT_HUGE_PAGECACHE For file mappings, we don't deposit page tables on THP allocation because it's not strictly required to implement split_huge_pmd(): we can just clear pmd and let following page faults to reconstruct the page table. But Power makes use of deposited page table to address MMU quirk. Let's hide THP page cache, including huge tmpfs, under separate config option, so it can be forbidden on Power. We can revert the patch later once solution for Power found. Link: http://lkml.kernel.org/r/1466021202-61880-36-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Cc: Aneesh Kumar K.V Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'mm/memory.c') diff --git a/mm/memory.c b/mm/memory.c index 712790e95f08..4425b6059339 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2920,7 +2920,7 @@ map_pte: return 0; } -#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE #define HPAGE_CACHE_INDEX_MASK (HPAGE_PMD_NR - 1) static inline bool transhuge_vma_suitable(struct vm_area_struct *vma, @@ -3002,7 +3002,8 @@ int alloc_set_pte(struct fault_env *fe, struct mem_cgroup *memcg, pte_t entry; int ret; - if (pmd_none(*fe->pmd) && PageTransCompound(page)) { + if (pmd_none(*fe->pmd) && PageTransCompound(page) && + IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) { /* THP on COW? */ VM_BUG_ON_PAGE(memcg, page); -- cgit v1.2.3-59-g8ed1b