Re: [PATCH 7/9] jbd2: make the whole kjournald2 kthread NOFS safe
From: Jan Kara <jack@suse.cz>
Date: 2016-12-16 08:40:57
Also in:
ceph-devel, linux-btrfs, linux-f2fs-devel, linux-fsdevel, linux-mm, linux-nfs, linux-xfs, lkml
On Thu 15-12-16 15:07:13, Michal Hocko wrote:
From: Michal Hocko <mhocko@suse.com> kjournald2 is central to the transaction commit processing. As such any potential allocation from this kernel thread has to be GFP_NOFS. Make sure to mark the whole kernel thread GFP_NOFS by the memalloc_nofs_save. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Michal Hocko <mhocko@suse.com>
Looks good to me. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza
quoted hunk ↗ jump to hunk
--- fs/jbd2/journal.c | 7 +++++++ 1 file changed, 7 insertions(+)diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c index 8ed971eeab44..6dad8c5d6ddf 100644 --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c@@ -206,6 +206,13 @@ static int kjournald2(void *arg) wake_up(&journal->j_wait_done_commit); /* + * Make sure that no allocations from this kernel thread will ever recurse + * to the fs layer because we are responsible for the transaction commit + * and any fs involvement might get stuck waiting for the trasn. commit. + */ + memalloc_nofs_save(); + + /* * And now, wait forever for commit wakeup events. */ write_lock(&journal->j_state_lock);-- 2.10.2
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