From 800d8c63b2e989c2e349632d1648119bf5862f01 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Tue, 26 Jul 2016 15:26:18 -0700 Subject: shmem: add huge pages support Here's basic implementation of huge pages support for shmem/tmpfs. It's all pretty streight-forward: - shmem_getpage() allcoates huge page if it can and try to inserd into radix tree with shmem_add_to_page_cache(); - shmem_add_to_page_cache() puts the page onto radix-tree if there's space for it; - shmem_undo_range() removes huge pages, if it fully within range. Partial truncate of huge pages zero out this part of THP. This have visible effect on fallocate(FALLOC_FL_PUNCH_HOLE) behaviour. As we don't really create hole in this case, lseek(SEEK_HOLE) may have inconsistent results depending what pages happened to be allocated. - no need to change shmem_fault: core-mm will map an compound page as huge if VMA is suitable; Link: http://lkml.kernel.org/r/1466021202-61880-30-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'mm/filemap.c') diff --git a/mm/filemap.c b/mm/filemap.c index 21508ea25717..e90c1543ec2d 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -219,8 +219,13 @@ void __delete_from_page_cache(struct page *page, void *shadow) /* hugetlb pages do not participate in page cache accounting. */ if (!PageHuge(page)) __mod_zone_page_state(page_zone(page), NR_FILE_PAGES, -nr); - if (PageSwapBacked(page)) + if (PageSwapBacked(page)) { __mod_zone_page_state(page_zone(page), NR_SHMEM, -nr); + if (PageTransHuge(page)) + __dec_zone_page_state(page, NR_SHMEM_THPS); + } else { + VM_BUG_ON_PAGE(PageTransHuge(page) && !PageHuge(page), page); + } /* * At this point page must be either written or cleaned by truncate. -- cgit v1.2.3