Re: [PATCH] xfs: fix race while discarding buffers [V4]
From: Dave Chinner <david@fromorbit.com>
Date: 2012-08-20 23:21:13
On Mon, Aug 20, 2012 at 07:47:51PM -0300, Carlos Maiolino wrote:
Hi Ben,quoted
Thanks for the comments.quoted
What was the symptom that led to the discovery of this problem? Reviewed-by: Ben Myers <redacted>It started with the messages like the example below being logged by syslog: shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-61993820 shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-146 shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-240601220 shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-152 shrink_slab: xfs_buftarg_shrink+0x0/0x160 [xfs] negative objects to delete nr=-2921236993 These messages came from shrink_slab().
Worth noting is that this warning came from a RHEL kernel, not a mainline kernel. The mainline kernels don't screw up the nr_to_scan calculations when a negative object count is returned to them. Hence mainline kernels are not impacted by the accounting bug at all... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs