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![]() 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> |
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.. | ||
acl.c | ||
acl.h | ||
balloc.c | ||
bitmap.c | ||
block_validity.c | ||
crypto.c | ||
crypto_fname.c | ||
crypto_key.c | ||
crypto_policy.c | ||
dir.c | ||
ext4.h | ||
ext4_crypto.h | ||
ext4_extents.h | ||
ext4_jbd2.c | ||
ext4_jbd2.h | ||
extents.c | ||
extents_status.c | ||
extents_status.h | ||
file.c | ||
fsync.c | ||
hash.c | ||
ialloc.c | ||
indirect.c | ||
inline.c | ||
inode.c | ||
ioctl.c | ||
Kconfig | ||
Makefile | ||
mballoc.c | ||
mballoc.h | ||
migrate.c | ||
mmp.c | ||
move_extent.c | ||
namei.c | ||
page-io.c | ||
readpage.c | ||
resize.c | ||
super.c | ||
symlink.c | ||
sysfs.c | ||
truncate.h | ||
xattr.c | ||
xattr.h | ||
xattr_security.c | ||
xattr_trusted.c | ||
xattr_user.c |