diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-07-26 15:26:35 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-26 16:19:19 -0700 |
| commit | e496cf3d782135c1cca0d154d4b924517ff58de0 (patch) | |
| tree | 884ae0082c0b344dd9200b28ca087a3cc0973fed /mm/memory.c | |
| parent | f3f0e1d2150b2b99da2cbdfaad000089efe9bf30 (diff) | |
| download | lwn-e496cf3d782135c1cca0d154d4b924517ff58de0.tar.gz lwn-e496cf3d782135c1cca0d154d4b924517ff58de0.zip | |
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 <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 5 |
1 files changed, 3 insertions, 2 deletions
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); |