btrfs: avoid monopolizing a core when activating a swap file

commit 2c8507c63f5498d4ee4af404a8e44ceae4345056 upstream. During swap activation we iterate over the extents of a file and we can have many thousands of them, so we can end up in a busy loop monopolizing a core. Avoid this by doing a voluntary reschedule after processing each extent. CC: [email protected] # 5.4+ Reviewed-by: Qu Wenruo <[email protected]> Signed-off-by: Filipe Manana <[email protected]> Signed-off-by: David Sterba <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
truenas · Jan 2, 2025 · 9f372e8 · 9f372e8
1 parent f6174bb
commit 9f372e8
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
@@ -7117,6 +7117,8 @@ noinline int can_nocow_extent(struct inode *inode, u64 offset, u64 *len,
 			ret = -EAGAIN;
 			goto out;
 		}
+
+		cond_resched();
 	}
 
 	if (file_extent)