We've had reports of soft lockup warnings in the iomap ioend
completion path due to very large bios and/or bio chains. Divert any
ioends with 256k or more pages to process to the workqueue so
completion occurs in non-atomic context and can reschedule to avoid
soft lockup warnings.
Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
---
fs/xfs/xfs_aops.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 3e061ea99922..84ee917014f1 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -30,6 +30,13 @@ XFS_WPC(struct iomap_writepage_ctx *ctx)
return container_of(ctx, struct xfs_writepage_ctx, ctx);
}
+/*
+ * Kick extra large ioends off to the workqueue. Completion will process a lot
+ * of pages for a large bio or bio chain and a non-atomic context is required to
+ * reschedule and avoid soft lockup warnings.
+ */
+#define XFS_LARGE_IOEND (262144 << PAGE_SHIFT)
+
/*
* Fast and loose check if this write could update the on-disk inode size.
*/
@@ -239,7 +246,8 @@ static inline bool xfs_ioend_needs_workqueue(struct iomap_ioend *ioend)
{
return ioend->io_private ||
ioend->io_type == IOMAP_UNWRITTEN ||
- (ioend->io_flags & IOMAP_F_SHARED);
+ (ioend->io_flags & IOMAP_F_SHARED) ||
+ (ioend->io_size >= XFS_LARGE_IOEND);
}
STATIC void
--
2.25.4
