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/huge_memory.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'mm/huge_memory.c') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index cabd53dac5b9..0f58460cd69c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3316,6 +3316,8 @@ static void __split_huge_page(struct page *page, struct list_head *list, if (head[i].index >= end) { __ClearPageDirty(head + i); __delete_from_page_cache(head + i, NULL); + if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head)) + shmem_uncharge(head->mapping->host, 1); put_page(head + i); } } -- cgit v1.2.3-55-g7522