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authorMichal Hocko <mhocko@suse.com>2016-07-27 01:24:53 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 02:19:19 +0300
commit8a5c743e308dd2b90ad10d1faaa7a1b09173a132 (patch)
treeba679ecefc77b4a80bd35b00e55ddc1457b14e07 /fs/cifs
parente5e3f4c4f0e95ecbad2f8d2f4f6a29bb8a90226b (diff)
downloadlinux-8a5c743e308dd2b90ad10d1faaa7a1b09173a132.tar.xz
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 <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Chris Mason <clm@fb.com> Cc: Steve French <sfrench@samba.org> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Jan Kara <jack@suse.cz> Cc: Mike Marshall <hubcap@omnibond.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Changman Lee <cm224.lee@samsung.com> Cc: Chao Yu <yuchao0@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/cifs')
-rw-r--r--fs/cifs/file.c2
1 files changed, 1 insertions, 1 deletions
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);