Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1507871

[PATCHv4 31/43] ext4: make ext4_mpage_readpages() hugepage-aware

From "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Newsgroups linux.kernel
Subject [PATCHv4 31/43] ext4: make ext4_mpage_readpages() hugepage-aware
Date 2016-10-25 02:30 +0200
Message-ID <svXMR-6y6-5@gated-at.bofh.it> (permalink)
References <svXDb-6uQ-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

This patch modifies ext4_mpage_readpages() to deal with huge pages.

We read out 2M at once, so we have to alloc (HPAGE_PMD_NR *
blocks_per_page) sector_t for that. I'm not entirely happy with kmalloc
in this codepath, but don't see any other option.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 fs/ext4/readpage.c | 39 +++++++++++++++++++++++++++++++++------
 1 file changed, 33 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index a81b829d56de..af8436a4702c 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -104,12 +104,12 @@ int ext4_mpage_readpages(struct address_space *mapping,
 
 	struct inode *inode = mapping->host;
 	const unsigned blkbits = inode->i_blkbits;
-	const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
 	const unsigned blocksize = 1 << blkbits;
 	sector_t block_in_file;
 	sector_t last_block;
 	sector_t last_block_in_file;
-	sector_t blocks[MAX_BUF_PER_PAGE];
+	sector_t blocks_on_stack[MAX_BUF_PER_PAGE];
+	sector_t *blocks = blocks_on_stack;
 	unsigned page_block;
 	struct block_device *bdev = inode->i_sb->s_bdev;
 	int length;
@@ -122,8 +122,9 @@ int ext4_mpage_readpages(struct address_space *mapping,
 	map.m_flags = 0;
 
 	for (; nr_pages; nr_pages--) {
-		int fully_mapped = 1;
-		unsigned first_hole = blocks_per_page;
+		int fully_mapped = 1, nr = nr_pages;
+		unsigned blocks_per_page = PAGE_SIZE >> blkbits;
+		unsigned first_hole;
 
 		prefetchw(&page->flags);
 		if (pages) {
@@ -138,10 +139,32 @@ int ext4_mpage_readpages(struct address_space *mapping,
 			goto confused;
 
 		block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits);
-		last_block = block_in_file + nr_pages * blocks_per_page;
+
+		if (PageTransHuge(page) &&
+				IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) {
+			BUILD_BUG_ON(BIO_MAX_PAGES < HPAGE_PMD_NR);
+			nr = HPAGE_PMD_NR * blocks_per_page;
+			/* XXX: need a better solution ? */
+			blocks = ext4_kvmalloc(sizeof(sector_t) * nr, GFP_NOFS);
+			if (!blocks) {
+				if (pages) {
+					delete_from_page_cache(page);
+					goto next_page;
+				}
+				return -ENOMEM;
+			}
+
+			blocks_per_page *= HPAGE_PMD_NR;
+			last_block = block_in_file + blocks_per_page;
+		} else {
+			blocks = blocks_on_stack;
+			last_block = block_in_file + nr * blocks_per_page;
+		}
+
 		last_block_in_file = (i_size_read(inode) + blocksize - 1) >> blkbits;
 		if (last_block > last_block_in_file)
 			last_block = last_block_in_file;
+		first_hole = blocks_per_page;
 		page_block = 0;
 
 		/*
@@ -213,6 +236,8 @@ int ext4_mpage_readpages(struct address_space *mapping,
 			}
 		}
 		if (first_hole != blocks_per_page) {
+			if (PageTransHuge(page))
+				goto confused;
 			zero_user_segment(page, first_hole << blkbits,
 					  PAGE_SIZE);
 			if (first_hole == 0) {
@@ -248,7 +273,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
 					goto set_error_page;
 			}
 			bio = bio_alloc(GFP_KERNEL,
-				min_t(int, nr_pages, BIO_MAX_PAGES));
+				min_t(int, nr, BIO_MAX_PAGES));
 			if (!bio) {
 				if (ctx)
 					fscrypt_release_ctx(ctx);
@@ -289,5 +314,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
 	BUG_ON(pages && !list_empty(pages));
 	if (bio)
 		submit_bio(bio);
+	if (blocks != blocks_on_stack)
+		kfree(blocks);
 	return 0;
 }
-- 
2.9.3

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCHv4 00/43] ext4: support of huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 02/43] radix tree test suite: Allow GFP_ATOMIC allocations to fail "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 34/43] ext4: handle huge pages in __ext4_block_zero_page_range() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 26/43] fs: make block_page_mkwrite() aware about huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 40/43] ext4: fix SEEK_DATA/SEEK_HOLE for huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 42/43] mm, fs, ext4: expand use of page_mapping() and page_to_pgoff() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 41/43] ext4: make fallocate() operations work with huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 09/43] mm, rmap: account file thp pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 35/43] ext4: make ext4_block_write_begin() aware about huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 06/43] mm, shmem: swich huge tmpfs to multi-order radix-tree entries "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 36/43] ext4: handle huge pages in ext4_da_write_end() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 10/43] thp: try to free page's buffers before attempt split "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 11/43] thp: handle write-protection faults for file THP "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:20 +0200
  [PATCHv4 18/43] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if huge page cache enabled "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
    Re: [PATCHv4 18/43] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if  huge page cache enabled Christoph Hellwig <hch@infradead.org> - 2016-10-25 09:30 +0200
      Re: [PATCHv4 18/43] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if  huge page cache enabled "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-10-26 00:40 +0200
        Re: [PATCHv4 18/43] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if huge page cache enabled Andreas Dilger <adilger@dilger.ca> - 2016-10-26 06:20 +0200
          Re: [PATCHv4 18/43] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if  huge page cache enabled Ming Lei <tom.leiming@gmail.com> - 2016-10-26 09:40 +0200
            Re: [PATCHv4 18/43] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if  huge page cache enabled Christoph Hellwig <hch@infradead.org> - 2016-10-26 09:40 +0200
          Re: [PATCHv4 18/43] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if  huge page cache enabled Christoph Hellwig <hch@infradead.org> - 2016-10-26 09:40 +0200
        Re: [PATCHv4 18/43] block: define BIO_MAX_PAGES to HPAGE_PMD_NR if  huge page cache enabled Christoph Hellwig <hch@infradead.org> - 2016-10-26 09:40 +0200
  [PATCHv4 30/43] mm: account huge pages to dirty, writaback, reclaimable, etc. "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 31/43] ext4: make ext4_mpage_readpages() hugepage-aware "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 17/43] HACK: readahead: alloc huge pages, if allowed "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 20/43] mm: make write_cache_pages() work on huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 21/43] thp: introduce hpage_size() and hpage_mask() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 01/43] tools: Add WARN_ON_ONCE "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 08/43] page-flags: relax page flag policy for few flags "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 39/43] ext4: make EXT4_IOC_MOVE_EXT work with huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 32/43] ext4: make ext4_writepage() work on huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 13/43] filemap: allocate huge page in page_cache_read(), if allowed "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 28/43] truncate: make invalidate_inode_pages2_range() aware about huge pages "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 03/43] radix-tree: Add radix_tree_join "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 15/43] filemap: allocate huge page in pagecache_get_page(), if allowed "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 29/43] mm, hugetlb: switch hugetlbfs to multi-order radix-tree entries "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 23/43] thp: make thp_get_unmapped_area() respect S_HUGE_MODE "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200
  [PATCHv4 24/43] fs: make block_read_full_page() be able to read huge page "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-10-25 02:30 +0200

csiph-web