From 6b524995a71d49ae032dba308d117dbf2a18d175 Mon Sep 17 00:00:00 2001 From: Ross Zwisler Date: Tue, 26 Jul 2016 15:21:05 -0700 Subject: dax: remote unused fault wrappers Remove the unused wrappers dax_fault() and dax_pmd_fault(). After this removal, rename __dax_fault() and __dax_pmd_fault() to dax_fault() and dax_pmd_fault() respectively, and update all callers. The dax_fault() and dax_pmd_fault() wrappers were initially intended to capture some filesystem independent functionality around page faults (calling sb_start_pagefault() & sb_end_pagefault(), updating file mtime and ctime). However, the following commits: 5726b27b09cc ("ext2: Add locking for DAX faults") ea3d7209ca01 ("ext4: fix races between page faults and hole punching") added locking to the ext2 and ext4 filesystems after these common operations but before __dax_fault() and __dax_pmd_fault() were called. This means that these wrappers are no longer used, and are unlikely to be used in the future. XFS has had locking analogous to what was recently added to ext2 and ext4 since DAX support was initially introduced by: 6b698edeeef0 ("xfs: add DAX file operations support") Link: http://lkml.kernel.org/r/20160714214049.20075-2-ross.zwisler@linux.intel.com Signed-off-by: Ross Zwisler Cc: "Theodore Ts'o" Cc: Alexander Viro Cc: Andreas Dilger Cc: Dan Williams Cc: Dave Chinner Reviewed-by: Jan Kara Cc: Jonathan Corbet Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ext4/file.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/ext4') diff --git a/fs/ext4/file.c b/fs/ext4/file.c index df44c877892a..6664f9c82005 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -202,7 +202,7 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) if (IS_ERR(handle)) result = VM_FAULT_SIGBUS; else - result = __dax_fault(vma, vmf, ext4_dax_get_block); + result = dax_fault(vma, vmf, ext4_dax_get_block); if (write) { if (!IS_ERR(handle)) @@ -237,7 +237,7 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, if (IS_ERR(handle)) result = VM_FAULT_SIGBUS; else - result = __dax_pmd_fault(vma, addr, pmd, flags, + result = dax_pmd_fault(vma, addr, pmd, flags, ext4_dax_get_block); if (write) { -- cgit v1.2.3 From 8a5c743e308dd2b90ad10d1faaa7a1b09173a132 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Tue, 26 Jul 2016 15:24:53 -0700 Subject: mm, memcg: use consistent gfp flags during readahead Vladimir has noticed that we might declare memcg oom even during readahead because read_pages only uses GFP_KERNEL (with mapping_gfp restriction) while __do_page_cache_readahead uses page_cache_alloc_readahead which adds __GFP_NORETRY to prevent from OOMs. This gfp mask discrepancy is really unfortunate and easily fixable. Drop page_cache_alloc_readahead() which only has one user and outsource the gfp_mask logic into readahead_gfp_mask and propagate this mask from __do_page_cache_readahead down to read_pages. This alone would have only very limited impact as most filesystems are implementing ->readpages and the common implementation mpage_readpages does GFP_KERNEL (with mapping_gfp restriction) again. We can tell it to use readahead_gfp_mask instead as this function is called only during readahead as well. The same applies to read_cache_pages. ext4 has its own ext4_mpage_readpages but the path which has pages != NULL can use the same gfp mask. Btrfs, cifs, f2fs and orangefs are doing a very similar pattern to mpage_readpages so the same can be applied to them as well. [akpm@linux-foundation.org: coding-style fixes] [mhocko@suse.com: restrict gfp mask in mpage_alloc] Link: http://lkml.kernel.org/r/20160610074223.GC32285@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1465301556-26431-1-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko Cc: Vladimir Davydov Cc: Chris Mason Cc: Steve French Cc: Theodore Ts'o Cc: Jan Kara Cc: Mike Marshall Cc: Jaegeuk Kim Cc: Changman Lee Cc: Chao Yu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/btrfs/extent_io.c | 3 ++- fs/cifs/file.c | 2 +- fs/ext4/readpage.c | 2 +- fs/f2fs/data.c | 3 ++- fs/mpage.c | 4 +++- fs/orangefs/inode.c | 2 +- include/linux/pagemap.h | 6 +++--- mm/readahead.c | 13 ++++++------- 8 files changed, 19 insertions(+), 16 deletions(-) (limited to 'fs/ext4') diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 75533adef998..e91d55837dd2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -4180,7 +4180,8 @@ int extent_readpages(struct extent_io_tree *tree, prefetchw(&page->flags); list_del(&page->lru); if (add_to_page_cache_lru(page, mapping, - page->index, GFP_NOFS)) { + page->index, + readahead_gfp_mask(mapping))) { put_page(page); continue; } diff --git a/fs/cifs/file.c b/fs/cifs/file.c index d4890b6dc22d..579e41b350a2 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -3366,7 +3366,7 @@ readpages_get_pages(struct address_space *mapping, struct list_head *page_list, struct page *page, *tpage; unsigned int expected_index; int rc; - gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL); + gfp_t gfp = readahead_gfp_mask(mapping); INIT_LIST_HEAD(tmplist); diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c index dc54a4b60eba..c75b66a64982 100644 --- a/fs/ext4/readpage.c +++ b/fs/ext4/readpage.c @@ -166,7 +166,7 @@ int ext4_mpage_readpages(struct address_space *mapping, page = list_entry(pages->prev, struct page, lru); list_del(&page->lru); if (add_to_page_cache_lru(page, mapping, page->index, - mapping_gfp_constraint(mapping, GFP_KERNEL))) + readahead_gfp_mask(mapping))) goto next_page; } diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 9a8bbc1fb1fa..c80dda4bdff8 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -996,7 +996,8 @@ static int f2fs_mpage_readpages(struct address_space *mapping, page = list_entry(pages->prev, struct page, lru); list_del(&page->lru); if (add_to_page_cache_lru(page, mapping, - page->index, GFP_KERNEL)) + page->index, + readahead_gfp_mask(mapping))) goto next_page; } diff --git a/fs/mpage.c b/fs/mpage.c index eedc644b78d7..c8a05901a37b 100644 --- a/fs/mpage.c +++ b/fs/mpage.c @@ -71,6 +71,8 @@ mpage_alloc(struct block_device *bdev, { struct bio *bio; + /* Restrict the given (page cache) mask for slab allocations */ + gfp_flags &= GFP_KERNEL; bio = bio_alloc(gfp_flags, nr_vecs); if (bio == NULL && (current->flags & PF_MEMALLOC)) { @@ -362,7 +364,7 @@ mpage_readpages(struct address_space *mapping, struct list_head *pages, sector_t last_block_in_bio = 0; struct buffer_head map_bh; unsigned long first_logical_block = 0; - gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL); + gfp_t gfp = readahead_gfp_mask(mapping); map_bh.b_state = 0; map_bh.b_size = 0; diff --git a/fs/orangefs/inode.c b/fs/orangefs/inode.c index 85640e955cde..06a8da75651d 100644 --- a/fs/orangefs/inode.c +++ b/fs/orangefs/inode.c @@ -80,7 +80,7 @@ static int orangefs_readpages(struct file *file, if (!add_to_page_cache(page, mapping, page->index, - GFP_KERNEL)) { + readahead_gfp_mask(mapping))) { ret = read_one_page(page); gossip_debug(GOSSIP_INODE_DEBUG, "failure adding page to cache, read_one_page returned: %d\n", diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 97354102794d..81363b834900 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -209,10 +209,10 @@ static inline struct page *page_cache_alloc_cold(struct address_space *x) return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD); } -static inline struct page *page_cache_alloc_readahead(struct address_space *x) +static inline gfp_t readahead_gfp_mask(struct address_space *x) { - return __page_cache_alloc(mapping_gfp_mask(x) | - __GFP_COLD | __GFP_NORETRY | __GFP_NOWARN); + return mapping_gfp_mask(x) | + __GFP_COLD | __GFP_NORETRY | __GFP_NOWARN; } typedef int filler_t(void *, struct page *); diff --git a/mm/readahead.c b/mm/readahead.c index 40be3ae0afe3..65ec288dc057 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -89,7 +89,7 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages, page = lru_to_page(pages); list_del(&page->lru); if (add_to_page_cache_lru(page, mapping, page->index, - mapping_gfp_constraint(mapping, GFP_KERNEL))) { + readahead_gfp_mask(mapping))) { read_cache_pages_invalidate_page(mapping, page); continue; } @@ -108,7 +108,7 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages, EXPORT_SYMBOL(read_cache_pages); static int read_pages(struct address_space *mapping, struct file *filp, - struct list_head *pages, unsigned nr_pages) + struct list_head *pages, unsigned int nr_pages, gfp_t gfp) { struct blk_plug plug; unsigned page_idx; @@ -126,10 +126,8 @@ static int read_pages(struct address_space *mapping, struct file *filp, for (page_idx = 0; page_idx < nr_pages; page_idx++) { struct page *page = lru_to_page(pages); list_del(&page->lru); - if (!add_to_page_cache_lru(page, mapping, page->index, - mapping_gfp_constraint(mapping, GFP_KERNEL))) { + if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) mapping->a_ops->readpage(filp, page); - } put_page(page); } ret = 0; @@ -159,6 +157,7 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp, int page_idx; int ret = 0; loff_t isize = i_size_read(inode); + gfp_t gfp_mask = readahead_gfp_mask(mapping); if (isize == 0) goto out; @@ -180,7 +179,7 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp, if (page && !radix_tree_exceptional_entry(page)) continue; - page = page_cache_alloc_readahead(mapping); + page = __page_cache_alloc(gfp_mask); if (!page) break; page->index = page_offset; @@ -196,7 +195,7 @@ int __do_page_cache_readahead(struct address_space *mapping, struct file *filp, * will then handle the error. */ if (ret) - read_pages(mapping, filp, &page_pool, ret); + read_pages(mapping, filp, &page_pool, ret, gfp_mask); BUG_ON(!list_empty(&page_pool)); out: return ret; -- cgit v1.2.3