The patch titled
Subject: jbd2: make the whole kjournald2 kthread NOFS safe
has been added to the -mm tree. Its filename is
jbd2-make-the-whole-kjournald2-kthread-nofs-safe.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/jbd2-make-the-whole-kjournald2-kthread-nofs-safe.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/jbd2-make-the-whole-kjournald2-kthread-nofs-safe.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: jbd2: make the whole kjournald2 kthread NOFS safe
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.
Link: http://lkml.kernel.org/r/20170306131408.9828-8-mhocko@xxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Suggested-by: Jan Kara <jack@xxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: Chris Mason <clm@xxxxxx>
Cc: David Sterba <dsterba@xxxxxxx>
Cc: Brian Foster <bfoster@xxxxxxxxxx>
Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Cc: Nikolay Borisov <nborisov@xxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/jbd2/journal.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff -puN fs/jbd2/journal.c~jbd2-make-the-whole-kjournald2-kthread-nofs-safe fs/jbd2/journal.c
--- a/fs/jbd2/journal.c~jbd2-make-the-whole-kjournald2-kthread-nofs-safe
+++ a/fs/jbd2/journal.c
@@ -43,6 +43,7 @@
#include <linux/backing-dev.h>
#include <linux/bitops.h>
#include <linux/ratelimit.h>
+#include <linux/sched/mm.h>
#define CREATE_TRACE_POINTS
#include <trace/events/jbd2.h>
@@ -206,6 +207,13 @@ 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);
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
lockdep-allow-to-disable-reclaim-lockup-detection.patch
xfs-abstract-pf_fstrans-to-pf_memalloc_nofs.patch
mm-introduce-memalloc_nofs_saverestore-api.patch
xfs-use-memalloc_nofs_saverestore-instead-of-memalloc_noio.patch
jbd2-mark-the-transaction-context-with-the-scope-gfp_nofs-context.patch
jbd2-make-the-whole-kjournald2-kthread-nofs-safe.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
