[0/2] iomap: avoid soft lockup warnings on large ioends

Message

Brian Foster Oct. 2, 2020, 3:33 p.m. UTC

Hi all,

My understanding is that there's still no real agreement on the proper
approach to address this problem. The RFC I floated [1] intended to cap
the size of ioends to avoid any latency issues with holding so many
pages in writeback for effectively a single completion instance of a GB+
sized I/O. Instead, Christoph preferred to dump those large bios onto
the completion workqueue and use cond_resched() rather than cap the
ioend size. This series implements the latter (for XFS) since it seems
like incremental progress and should at least address the warning.
Thoughts, reviews, flames appreciated.

Brian

[1] https://lore.kernel.org/linux-fsdevel/20200825144917.GA321765@bfoster/

Brian Foster (2):
  iomap: resched ioend completion when in non-atomic context
  xfs: kick extra large ioends to completion workqueue

 fs/iomap/buffered-io.c | 15 +++++++++------
 fs/xfs/xfs_aops.c      | 12 ++++++++++--
 include/linux/iomap.h  |  2 +-
 3 files changed, 20 insertions(+), 9 deletions(-)