summaryrefslogtreecommitdiffstats
path: root/include/linux/pagemap.h
diff options
context:
space:
mode:
authorMichal Hocko <mhocko@suse.com>2016-07-26 15:24:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-26 16:19:19 -0700
commit8a5c743e308dd2b90ad10d1faaa7a1b09173a132 (patch)
treeba679ecefc77b4a80bd35b00e55ddc1457b14e07 /include/linux/pagemap.h
parente5e3f4c4f0e95ecbad2f8d2f4f6a29bb8a90226b (diff)
downloadlinux-8a5c743e308dd2b90ad10d1faaa7a1b09173a132.tar.gz
linux-8a5c743e308dd2b90ad10d1faaa7a1b09173a132.tar.bz2
linux-8a5c743e308dd2b90ad10d1faaa7a1b09173a132.zip
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 'include/linux/pagemap.h')
-rw-r--r--include/linux/pagemap.h6
1 files changed, 3 insertions, 3 deletions
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 *);